Tag: Environment and Climate Change Canada

West nile virus

While the PPMN no longer predicts the development of Culex tarsalis, the dominant vector for West Nile Virus (WNV), areas of the Canadian prairies in 2024 have received high levels of precipitation. This is noteworthy because the larvae of C. tarsalis can develop in, “agricultural tailwater, alkaline lake beds, fresh and saline wetlands, secondary treated sewage effluent and oil field run-off” (Centre for Vector Biology URL retrieved 2024Jul04).

Culex tarsalis have a base developmental threshold of 14.3 °C. Across the Canadian prairies, WNV transmission is of greatest concern as the second generation of C. tarsalis females begin to fly (by 250-300 degree days). In fact, an additional 109 degree days (using Base 14.3 °C) is required within a given mosquito population for virus development to complete to the point that transmission might occur.

Historically, by mid-July, C. tarsalis adults begin to fly in southern parts of the Canadian prairies. By August, protect yourself from mosquitoes when outdoors – this is the window when mosquitoes are most numerous plus have the greatest chance of carrying WNV. Field scouts and outdoor enthusiasts should wear DEET to protect against C. tarsalis and WNV.

For reference, the following table of data was quickly generated using AAFC Drought Watch Historical Daily Air Temperatures since April 1, 2024:

Location	Degree Days (base 14.3 °C) as of August 21, 2024	Observed date heat units >200 Degree Days	Potential date when >390 Degree Days attained
Winnipeg	384.0	July 20	August 24
Brandon	302.8	July 27	Unable to project
Regina	352.9	July 26	September 2
Saskatoon	320.4	July 29	Unable to project
Lethbridge	331.2	July 25	Unable to project
Edmonton	205.9	August 20	Unable to project
Grande Prairie	239.2	August 11	Unable to project

Note: Potential dates calculated using daily mean of 18°C until August 30, 2024, then daily mean of 15°C for September 1-30, 2024.

The Public Health Agency of Canada posts information related to West Nile Virus in Canada. Link here to view the latest case numbers and seasonal updates. Bird surveillance continues to be an important way to detect and monitor West Nile Virus. The Canadian Wildlife Health Cooperative (CWHC) works with governmental agencies (i.e., provincial laboratories and the National Microbiology Laboratory) and other organizations to report the occurrence of WNV. Access information on surveillance posted by the provinces of Manitoba, Saskatchewan, or Alberta.

Weekly Wind Trajectory Report for June 27

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies have originated from the Pacific Northwest (Idaho, Oregon and Washington). This past week (June 21-27, 2022) the number of incoming trajectories was lower than the week of June 14-20, 2022 (Fig. 1).

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **June 1-27, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories continue to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (June 21-27, 2022) the ECCC model predicted that 77 reverse trajectories would cross the prairies. This is significantly less than the number of reverse trajectories predicted for the period of June 14-20 (n=124).

Figure 2. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and June 27, 2022.

b. Mexico and southwest USA (Texas, California) – This week (June 21-27, 2022), a total of 13 reverse trajectories were predicted to cross the prairies (n=44 for June 14-20). Most reverse trajectories from this region of southern North America have crossed Manitoba during the 2022 growing season.

Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and June 27, 2022.

c. Oklahoma and Texas – This week reverse trajectories have passed over Manitoba and Watrous, Saskatchewan (Fig. 4). This week there were significantly fewer (n=5) reverse trajectories than for the period of June 14-20, 2022 (n=33).

Figure 4. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and June 27, 2022.

d. Nebraska and Kansas – This past week (June 21-27, 2022), reverse trajectories originating from Kansas and Nebraska have crossed Manitoba and Yorkton, Saskatchewan (Fig. 5). The ECCC model predicted that 5 reverse trajectories passed over the prairies. This is a significant decrease from the previous week (n=51).

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and June 27, 2022.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (June 21-27, 2022) there was a decrease in the number of (n=19) forward trajectories predicted to cross the prairies (last week n=50). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

Figure 6. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between **April 1 and June 27, 2022**.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for June 20

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies have originated from the Pacific Northwest (Idaho, Oregon and Washington). The number of incoming trajectories during the first two weeks of June was much lower than this past week (June 14-20, 2022) (Fig. 1). The number of reverse trajectories, originating from Mexico, California, Texas, Oklahoma, Nebraska and Kansas have significantly increased since June 18th.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **June 1-20, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (June 14-20, 2022) the ECCC model predicted that 124 reverse trajectories would cross the prairies. This is similar to the number of reverse trajectories expected in the previous week (n=134).

b. Mexico and southwest USA (Texas, California) – Prior to this past week, the most recent reverse trajectories that originated from Mexico, California or Texas crossed over the Canadian prairies on May 31st. This week a total of 44 reverse trajectories were predicted to cross the prairies. Most reverse trajectories have entered Manitoba during the 2022 growing season. This week trajectories crossed Medicine Hat, Kindersley, and Swift Current.

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan. This week, a number of these reverse trajectories passed over central Saskatchewan, including Saskatoon, Moose Jaw and Regina (Fig. 4). This week there were significantly more (n=44) reverse trajectories than last week (n=1) that originated from Texas and Oklahoma.

d. Nebraska and Kansas – Similar to last week, a number of reverse trajectories originating from Kansas and Nebraska have crossed central and western prairie locations (Fig. 5). This past week (June 14-20, 2022) the ECCC model predicted that 51 reverse trajectories passed over the prairies. This is a significant increase from the previous week (n=8).

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for June 13

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). This past week (June 7-13, 2022) the number of reverse trajectories originating from Mexico, California, Texas, Oklahoma, Nebraska and Kansas continued to be low. This week reverse trajectories generally originated over the Pacific Ocean before entering the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **June 1-13, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (June 7-13, 2022) the ECCC model predicted that 134 reverse trajectories would cross the prairies. This is a significant increase over the previous week (n=26).

b. Mexico and southwest USA (Texas, California) – This past week (June 7-13, 2022) the model reported that zero reverse trajectories that originated from Mexico, California or Texas crossed over the Canadian prairies. Since May 1, 2022, these trajectories have been restricted to Manitoba and eastern Saskatchewan (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan. This past week (June 7-13, 2022) one trajectory crossed over Edmonton, Alberta.

d. Nebraska and Kansas – Until this week, reverse trajectories originating from Kansas and Nebraska have been associated with southeastern Saskatchewan and southern Manitoba (Fig. 5). This past week (June 7-13, 2022) the ECCC model predicted that 8 reverse trajectories passed over the prairies. Six of these reverse trajectories passed over parts of Alberta, including Beiseker, Olds, Edmonton, Rycroft, and Fort Vermilion and Fort St. John in British Columbia.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (May 31 to June 6, 2022) there The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (June 7-13, 2022) there was an increase in the number of forward trajectories (n=34) predicted to cross the prairies compared to last week (n=12). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for June 6

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, there was a significant decrease in the number of trajectories that were predicted to cross over the prairies from May 31 – June 6, 2022. This week reverse trajectories generally originated over the arctic before entering the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-June 6, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (May 31-June 6, 2022) the ECCC model predicted that 26 reverse trajectories passed over the prairies. This is a significant decrease compared to the previous week (n=124).

b. Mexico and southwest USA (Texas, California) – This past week (May 31 to June 6, 2022) reverse trajectories that originated from Mexico, California or Texas crossed over Carman and Selkirk (May 31, 2022). Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). This past week (May 31 to June 6, 2022) there has been an increase in the number of reverse trajectories that have crossed over southeastern Saskatchewan (Weyburn and Gainsborough) and Manitoba (Portage and Brandon).

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska, have crossed southeastern Saskatchewan and southern Manitoba (Fig. 5). This past week (May 31 to June 6, 2022) the ECCC model predicted that 6 reverse trajectories passed over the prairies. This is a significant decrease compared to the previous week (n=27).

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for May 30

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 24-30, 2022) there was a significant increase in the number of trajectories (PNW, OK/TX and NE/KS) that passed over the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-30, 2022**.

b. Mexico and southwest USA (Texas, California) – This past week there have not been any reverse trajectories that originated from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). This past week (May 24-30, 2022) there was an increase in the number of reverse trajectories that have crossed over southeastern Saskatchewan (Weyburn and Gainsborough) and Manitoba (Portage and Brandon) relative to previous weeks.

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5). This past week (May 24-30, 2022) there was an increase in the number of reverse trajectories that have crossed over eastern Saskatchewan and Manitoba relative to previous weeks.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for May 23

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 17-23, 2022) there were fewer trajectories passing over the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-23, 2022**.

b. Mexico and southwest USA (Texas, California) – This past week there were no reverse trajectories originating from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). No trajectories were predicted for May 17-23, 2022.

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5).

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) predicted to cross the Canadian prairies (Fig. 6). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

Weekly Wind Trajectory Report for May 16

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1).

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-16, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have passed over south-central Alberta and western Saskatchewan (link to view Fig. 2).

b. Mexico and southwest USA (Texas, California) – Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (link to view Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (link to view Fig. 4).

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) predicted to cross the Canadian prairies (Fig. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

Figure 5. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between **April 1 and May 16, 2022**.

Weekly Wind Trajectory Report for June 28

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since June 16, 2021, a decreasing number of reverse trajectories have moved north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 28 – June 28, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 22-28, 2021) there were 3 trajectories that crossed Alberta, Manitoba and Saskatchewan that originated in the Pacific Northwest.

b. Mexico and southwest USA (Texas, California) – This week (June 22-28, 2021) there were 0 trajectories that originated in Mexico or the southwest USA that crossed the prairies.

c. Oklahoma and Texas – This week (June 22-28, 2021) there were 0 trajectories originating in Oklahoma or Texas that passed over the prairies.

d. Kansas and Nebraska – This week (June 22-28, 2021) there were 0 trajectories that originated in Kansas or Nebraska that passed over the prairies.

2. FORWARD TRAJECTORIES (FT)
a. Since June 9, 2021 there has been a steady decrease in the number of forward trajectories that are predicted to cross the prairies (Fig. 2). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line).

Figure 2. The average number (based on a 5 day running average) of forward trajectories that were predicted to cross the prairies for the period of May 28-June 28, 2021.

Weather synopsis

TEMPERATURE: This past week (June 14-20, 2021), weekly temperatures were above normal and rainfall amounts for Saskatchewan and Manitoba were less than 5 mm. The warmest temperatures were observed across the southern and central regions of Alberta as well as western Saskatchewan (Fig. 1).

Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of June 14 – 20, 2021.

Across the prairies, the average 30-day (May 22 – June 20) temperature was 1.4 °C warmer than climate normal values. The warmest temperatures were observed across southern Manitoba (Fig. 2). The 2021 growing season (April 1 – June 20, 2021) has been characterized by near normal temperatures. The warmest temperatures have occurred across southern and central regions of the three prairie provinces (Fig. 3).

Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of May 22 – June 20, 2021.

Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 – June 20, 2021.

Growing degree day (GDD) maps for Base 5 ºC and Base 10 ºC (April 1-Jun 21, 2021) can be viewed by clicking the hyperlinks. Over the past 7 days (June 10-16, 2021), the lowest temperatures recorded across the Canadian prairies ranged from < -33 to >3 °C while the highest temperatures observed ranged from <24 to >36 °C. Access these maps and more using the AAFC Drought Watch webpage interface.

PRECIPITATION: This week, the highest rainfall amounts were reported across the Peace River region. Minimal rainfall was reported across most of Manitoba (Fig. 4). Rainfall amounts for the period of May 22-June 20 (30-day accumulation) were above normal (150 % of long-term average values). Rainfall amounts have been above normal for northeastern Alberta, most of Saskatchewan, and western and central regions of Manitoba (Fig. 5).

Figure 4. 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 14 -20, 2021.

Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 22 – June 20, 2021

The average growing season (April 1 – June 20) precipitation was 116 % of normal with the greatest precipitation occurring across central Alberta, eastern Saskatchewan, including Regina, and an area extending from Brandon to Winnipeg. Below normal rainfall has been reported across western Saskatchewan and southern Alberta (Fig. 6).

Figure 7. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-June 20, 2021.

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch Historical website, Environment Canada’s Historical Data website, or your provincial weather network.

Weekly Wind Trajectory Report for June 21

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since June 16, 2021, there have been a decreasing number of reverse trajectories that moved north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1).

Figure 1. The average number (based on a 5-day running average) of reverse trajectories that have crossed the prairies for the period of May 21 – June 21, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 16-21, 2021) there have been 43 trajectories that have crossed Alberta, Manitoba and Saskatchewan that originated in the Pacific Northwest (Fig. 2).

Figure 2. Total number of dates with reverse trajectories originating over the Pacific Northwest (Idaho, Oregon, and Washington) and have crossed the prairies **between March 24 and June 21, 2021**.

b. Mexico and southwest USA (Texas, California) – This week (June 16 – 21, 2021) there have been 3 trajectories that originated in Mexico or the southwest USA that have crossed the prairies.

c. Oklahoma and Texas – This week (June 16 – 21, 2021) there have been 4 trajectories originating in Oklahoma or Texas that have passed over the prairies.

d. Kansas and Nebraska – This week (June 16 – 21, 2021) there have been 8 trajectories that originated in Kansas or Nebraska that passed over the prairies.

2. FORWARD TRAJECTORIES (FT)
a. Since June 9, 2021, there has been a steady decrease in the number of forward trajectories that are predicted to cross the prairies (Fig. 3). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line).

Figure 3. The average number (based on a 5 day running average) of forward trajectories that were predicted to cross the prairies for the period of May 21-June 21, 2021.

Weekly Wind Trajectory Report for June 15

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Similar to last week, this week there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Though this US region can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 15 – June 15, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 11-15, 2021) there were 109 trajectories (versus 106 last week) that crossed Alberta, Manitoba and Saskatchewan (Fig. 2).

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 3). This week (June 11-15, 2021) there have been 11 trajectories (10 last week) that originated in Mexico or the southwest USA that have crossed the prairies.

Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas and have crossed the prairies between March 24 and June 15, 2021.

c. Oklahoma and Texas – The majority of these trajectories passed over Manitoba and eastern Saskatchewan (Fig. 4). This week (June 11-15, 2021) there were 18 trajectories (13 last week) originating in Oklahoma or Texas that passed over the prairies.

Figure 4. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and June 15, 2021.

d. Kansas and Nebraska – This week (June 11-15, 2021) there were 20 trajectories (19 last week) that originated in Kansas or Nebraska that passed over the prairies (Fig. 5).

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and June 15, 2021.

2. FORWARD TRAJECTORIES (FT)
a. This week there was a decrease in the number of forward trajectories predicted to cross the prairies (Fig. 6). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that there will be increased potential for introduction of DBM to the prairies.

Figure 6. The average number (based on a 5 day running average) of forward trajectories that were predicted to cross the prairies for the period of May 15-June 15, 2021.

Weekly Wind Trajectory Report for June 10

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
This past week (in particular June 9 and 10) there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 106 trajectories (53 last week) that have crossed Alberta, Manitoba and Saskatchewan. This growing season, PNW trajectories have crossed all parts of the prairies (Fig. 2).

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in the number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 3). This week there have been 10 trajectories (0 last week) that originated in Mexico or the southwest USA that have crossed the prairies (Fig. 3).

c. Oklahoma and Texas – This week there have been 13 trajectories (0 last week) originating in Oklahoma or Texas that have passed over the prairies (Fig. 4).

d. Kansas and Nebraska – This week there were 19 trajectories (versus 1 last week) that originated in Kansas or Nebraska that passed over the prairies (Fig. 5). Relative to the reverse trajectories associated with Oklahoma and Texas (Fig. 4), the trajectories from Kansas and Nebraska have crossed further into Alberta (Fig. 5).

2. FORWARD TRAJECTORIES (FT)
a. Continuing a trend that began last week, this week there was an increase in the number of forward trajectories predicted to cross the prairies (Fig. 6). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that there will be increased potential for introduction of DBM to the prairies.

Weather synopsis

TEMPERATURE: This past week (May 24-30, 2021) the average temperature across the prairies was 1 °C cooler than normal (Fig. 1). Temperatures were warmest across most of Alberta and coolest across Saskatchewan and central regions of Manitoba. Across the prairies, the average 30-day (May 1-30) temperature was almost 2 °C warmer than last week and similar to climate normal values. Warmest temperatures were observed across southern Manitoba (Table 1; Fig. 2).

Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of May 24-30, 2021.

Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of May 1-30, 2021.

The 2021 growing season (April 1 – May 31) has been characterized by near-normal temperatures. Temperatures have been warmest for southern Manitoba, western Saskatchewan and southern Alberta (Table 2; Fig. 3).

Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1-May 30, 2021.

The growing degree day map (GDD) (Base 5 ºC, April 1-May 31, 2021) is provided below (Fig. 4) while the growing degree day map (GDD) (Base 10 ºC, April 1-May 31, 2021) is shown in Figure 5.

**Figure** 4. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 31, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure** 5. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 31, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Several areas were on the receiving end of frost and many folks are still watching to see how their crops recover. The lowest temperatures recorded ranged from <-14 to >0 °C (Fig. 6) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <11 to >25 °C (Fig. 7).

**Figure 6**. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 27-Jun 2, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021) although PDF file format was not available. Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure 7**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 27-Jun 2, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021) although PDF file format was not available. Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

PRECIPITATION: This week, significant precipitation was reported across central regions of Saskatchewan and Alberta while minimal rain was reported across Manitoba and western Alberta (Fig. 8). Rainfall amounts for the period of May 1-30 (30-day accumulation) were 123 % of long-term average values. Rainfall amounts have been near normal to above normal for large areas of Alberta and southern Saskatchewan. Well above normal rain was reported for Edmonton and Regina. Below normal rainfall amounts were reported for central and northern areas of the Peace River region and across Manitoba (Table 1; Fig. 9).

Figure 8. 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 24-30, 2021.

Figure 9. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 1-30, 2021.

Average growing season (April 1 – May 30) precipitation was 105 % of normal with the greatest precipitation occurring near Edmonton and across eastern Saskatchewan. Most of Manitoba and the Peace River region have had 60 % or less of normal precipitation during the 2021 growing season so far (Table 2; Fig. 10).

Figure x. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-May 30, 2021.

Access ALL the PPMN’s Wind Trajectory reports (Weekly and Daily).

Access Environment and Climate Change Canada’s weather radar mapping interface. Options to access preceeding precipitation events include clicking off either an 1 or 3 hours time interval, using an 8-colour or 14-colour index. or changing the base map.

Weekly Wind Trajectory Report for June 3

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
This past week there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Though this US region can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 15 – June 3 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there were 53 trajectories (compared to 36 last week) that crossed Alberta, Manitoba and Saskatchewan. In previous years, the majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. However, tis growing season, PNW trajectories have crossed all parts of the prairies (Figs. 2 and 3).

Figure 2. Total number of reverse trajectories originating across Idaho, Oregon, and Washington and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 3. Total number of dates with reverse trajectories originating over the Pacific Northwest (Idaho, Oregon, and Washington) and have crossed the prairies between March 24 and June 3, 2021.

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in the number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 4). This week there were no trajectories (compared to 54 last week) that originated in Mexico or the southwest USA that crossed the prairies (Fig. 5).

Figure 4. Total number of reverse trajectories originating across Mexico, California and Texas and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 5. The total number of dates with reverse trajectories originating over Mexico, California and Texas and have crossed the prairies between March 24 and June 3, 2021.

c. Oklahoma and Texas – The majority of these trajectories have passed over Manitoba and eastern Saskatchewan (Fig. 6). This week there were no trajectories (compared to 51 last week) originating in Oklahoma or Texas that passed over the prairies (Fig. 7).

Figure 6. Total number of reverse trajectories originating across Oklahoma and Texas and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 7. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and June 3, 2021.

d. Kansas and Nebraska – Similar to results for Oklahoma and Texas, the majority of these trajectories crossed Manitoba and eastern Saskatchewan (Fig. 8). This week there was one trajectory that originated in Kansas or Nebraska that passed over Carman, Manitoba (Fig. 9). Relative to the reverse trajectories associated with Oklahoma and Texas, the trajectories from Kansas and Nebraska have crossed further into Alberta (Fig. 9).

Figure 8. Total number of reverse trajectories originating across Kansas and Nebraska and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 9. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and June 3, 2021.

2. FORWARD TRAJECTORIES (FT)
a. Continuing a trend that began last week, this week there was a decrease in the number of forward trajectories that were predicted to cross the prairies (Fig. 10). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there will be decreased potential for the introduction of DBM to the prairies.

Figure 10. The average number (based on a 5-day running average) of forward trajectories that were predicted to cross the prairies for the period of May 15-June 3, 2021.

Weekly Wind Trajectory Report for May 28

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). For the past two weeks there have been an increasing number of reverse trajectories that moved north from Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Compared to previous years, the number incoming trajectories (May) has increased. Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for
the period of May 1 – 27 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 36 trajectories (44 last week) that have crossed Alberta, Manitoba and Saskatchewan. In previous years, the majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. This growing season, PNW trajectories have crossed all parts of the prairies (Fig. 2). Compared to this time last year there has been a significant increase in the number of trajectories that have crossed Manitoba and eastern Saskatchewan.

Figure 2. Total number of dates with reverse trajectories originating over Pacific Northwest (Idaho, Oregon, and Washington) and
have crossed the prairies between March 24 and May 27, 2021.

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in number of trajectories from the southern US. This week there have been 54 trajectories (15 last week) that originated in Mexico and the southwestern US that have crossed the prairies (Fig. 3).

c. Oklahoma and Texas – This week there have been 51 trajectories (16 last week) that have passed over Manitoba, Saskatchewan and eastern Alberta that originated in Oklahoma or Texas (Fig. 4).

d. Kansas and Nebraska – This week there have been 63 trajectories (35 last week) that originated in Kansas or Nebraska that have passed over the prairies (Fig. 5). Relative to the reverse trajectories associated with Oklahoma and Texas, the trajectories from Kansas and Nebraska have crossed further into Alberta.

2. FORWARD TRAJECTORIES (FT)
a. Forward trajectories, originating from Mexico and USA, have crossed a number of prairie locations since May 1, 2021. This week there has been a decrease in the number of trajectories that are predicted to cross the prairies (Fig. 6). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there may be increased potential for the introduction of DBM to the prairies.

Figure 6. The average number (based on a 5-day running average) of forward trajectories that have crossed
the prairies for the period of May 1- 27, 2021.

Weather synopsis

TEMPERATURE: This past week (May 17-23, 2021) began with hot dry conditions followed by cool/wet conditions (mid-week reports of snow and minimum temperatures less than 0 °C). Most of the prairies had significant rainfall over the weekend. The average temperature across the prairies was 1 °C cooler than normal (Fig. 1). For the second week temperatures were warmest across Manitoba. Temperatures were coolest across western Saskatchewan and most of Alberta.

Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of May 17-23, 2021.

The prairie-wide average 30-day temperature (April 24- May 23) was 0.4 °C less than climate normal values. The warmest temperatures were observed across the southern prairies (Table 1; Fig. 2). The 2021 growing season (April 1 – May 16) has been characterized by near-normal temperatures. Temperatures have been similar across the prairies (Table 2; Fig. 3).

Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of April 24-May 23, 2021.

Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1-May 23, 2021.

The growing degree day map (GDD) (Base 5 ºC, April 1-May 24, 2021) is provided below (Fig. 4) while the growing degree day map (GDD) (Base 10 ºC, April 1-May 24, 2021) is shown in Figure 5.

**Figure** 4. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 24, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (27May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure 5**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 24, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (27May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Many were uttering the f-word this past week… several areas were on the receiving end of frost and many folks are still watching to see how their crops recover. The lowest temperatures recorded ranged from <-14 to >0 °C (Fig. 6) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <11 to >25 °C (Fig. 7).

**Figure 6**. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 20-26, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (27May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure 7**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 12-18, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

PRECIPITATION: This week average precipitation for the prairies was 17 mm (Fig. 8). Last week the average was less than 2 mm. Conditions continued to be dry in a large region bounded by Swift Current, Saskatoon and Vegreville as well as central and northern areas of the Peace River region. Rainfall amounts for the period of April 24-May 23 (30-day accumulation) were 88 % of long-term average values. Rainfall was greatest for large areas of Alberta, southern Saskatchewan and southern Manitoba (Table 1; Fig. 9). Average growing season (April 1 – May 23) precipitation was 86 % of normal (Table 1; Fig. 10). The map indicates that conditions continue to be very dry across the Peace River region, east-central Alberta, and west-central Saskatchewan.

Figure 8. 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 17-23, 2021.

Figure 9. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of April 24-May 23, 2021.

Figure 10. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-May 23, 2021.

Access ALL the PPMN’s Wind Trajectory reports (Weekly and Daily).

Weekly Wind Trajectory Report for May 20

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week there have been an increasing number of reverse trajectories that moved north from Texas, Oklahoma and Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

**Figure 1.** The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for
the period of May 1- 20, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 44 trajectories (27 last week) that have crossed Alberta, Manitoba, and Saskatchewan. The majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. This growing season, PNW trajectories have crossed all of the prairies (Fig. 2).

b. Mexico and southwest USA (Texas, California) – This week there have been 15 trajectories that originated in Mexico and the southwestern US that have crossed Manitoba and Saskatchewan.

c. Oklahoma and Texas – This week there have been 16 trajectories that have passed over Manitoba and Saskatchewan (Fig. 3) that originated in Oklahoma or Texas. These are the first trajectories, that originated over Oklahoma and Texas, to enter the prairies during the month of May.

**Figure 3**. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the
prairies between March 24 and May 20, 2021.

d. Kansas and Nebraska – This week there have been 35 trajectories (8 last week) that originated in Kansas or Nebraska that have passed over Manitoba and Saskatchewan (Fig. 4).

**Figure 4.** The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the
prairies between March 24 and May 20, 2021.

2. FORWARD TRAJECTORIES (FT)
a. Forward trajectories, originating from Mexico and USA, have crossed a number of prairie locations since May 1, 2021. This week, there has been a steady increase in the number of trajectories that are predicted to cross the prairies (Fig. 5). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there may be increased potential for the introduction of DBM to the prairies.

**Figure 5.** The average number (based on a 5 day running average) of forward trajectories that have crossed the
Canadian prairies for the period of May 1- 20, 2021.

The following map presents the total number of forward trajectories that have crossed the Canadian prairies (since March 24, 2021) (Fig. 6). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

**Figure 6.** The total number of dates with forward trajectories, originating from various regions of the United States and
Mexico, crossed the prairies between March 24 and May 20, 2021.

Earlier in the week, an Alert related to wind trajectories assessed over May 18-19, 2021, was shared by the PPMN. It communicated the anticpated arrival of several air masses arriving across the Canadian prairies over the next few days that originated from multiple areas of USA. Remember, the current WEEKLY REPORT (above) summarizes daily data over a longer, more comprehensive period.

Weather synopsis

TEMPERATURE: This past week the average temperature across the prairies was 2.5 °C warmer than normal (Fig. 1). Temperatures were warmest across the Parkland region in Manitoba, Saskatchewan, and Alberta.

Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of May 10-16, 2021.

The prairie-wide average 30-day temperature (April 17- May 16) was 0.9 °C less than climate normal values. A region from Winnipeg to Saskatoon has been 2 to 4 °C cooler than average. Temperatures have been warmest across southern Alberta (Table 1; Fig. 2).

Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of April 17-May 16, 2021.

The 2021 growing season (April 1 – May 16) has been characterized by near normal temperatures. Warmest temperatures were observed in a region between Lethbridge, Saskatoon and Edmonton while coolest temperatures were reported from Manitoba (Table 2; Fig. 3).

Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1-May 16, 2021.

The growing degree day map (GDD) (Base 5 ºC, April 1-May 2, 2021) is provided below (Fig. 4) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 5.

**Figure** 4. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 17, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure 5**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 17, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

At this early point in the growing season, cool temperatures pose the risk of frost but the differences between low and high temperatures can exert stress on plants, particularly when field conditions are dry. The lowest temperatures recorded ranged from <-8 to >6 °C (Fig. 6) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <3 to >28 °C (Fig. 7).

**Figure 6**. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 12-18, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

PRECIPITATION: Seven-day cumulative rainfall amounts indicate that most of the prairies had less than 2 mm of rain in the past week (Fig. 8). Rainfall amounts for the period of April 17-May 16 (30-day accumulation) were 56 % of long-term average values. Rainfall was greatest for southwestern Saskatchewan and across most of Alberta (Table 1; Fig. 9).

Figure 8 . 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 10-16, 2021.

Figure 9. 30 day cumulative rainfall (mm) observed across the Canadian prairies for the period of April 17-May 16, 2021.

Average growing season (April 1 – May 16) precipitation has been well below average for most of the prairies (35 % less than normal). Saskatoon has reported 4.3 mm (15 % of normal) and most of Saskatchewan and Manitoba have had less than 15 mm (40 % of normal precipitation) (Table 1; Fig. 10).

Figure 10. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-May 16, 2021.

Access ALL the PPMN’s Wind Trajectory reports (Weekly and Daily).

Access Environment and Climate Change Canada’s weather radar mapping interface. Options to access preceding precipitation events include clicking off either an 1 or 3 hours time interval, using an 8-colour or 14-colour index. or changing the base map.

ALERT – Wind Trajectory Report for May 19

Access background information for how and why wind trajectories are monitored in this earlier post.

Alert: Yesterday and today ECCC models produced results that suggest a number of RT’s for prairie locations. Compared to previous dates, the ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. The weather forecast may result in downward movement of DBM.

Details: There has been a significant increase in the number of trajectories, originating over a number of states in the USA, that have crossed the prairies (Fig. 1). These air currents may introduce diamondback moths to the prairies. ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed Alberta, Saskatchewan and western Manitoba (Fig. 2). Trajectories originating over Texas and Oklahoma have passed over eastern Saskatchewan and Manitoba (Fig. 3). A third group of trajectories, originating across Kansas and Nebraska have also crossed eastern Saskatchewan and Manitoba (Fig. 4).

Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicaceae family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

Action: The ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. Areas highlighted in green in Figures 2, 3, and 4 of this alert may receive downward movement of DBM very shortly. The presence of any Brassicaceae plant will provide a host for incoming DBM so scout volunteers and emerging canola. If DBM were carried north on air currents it may take a few days for DBM to show up in traps.

**Figure 1**. Summary of the average number (5 day running average) of reverse trajectories that have crossed the Canadian prairies (May 1-19, 2021)

**Figure 2**. The green region indicates the potential for introduction of diamondback moths from the Pacific Northwest (Idaho, Oregon, and Washington) to the Canadian prairies (May 18-19, 2021).

**Figure 3**. The green region indicates the potential for introduction of diamondback moths from Texas and Oklahoma to
the Canadian prairies (May 18-19, 2021).

**Figure 4**. The green region indicates the potential for introduction of diamondback moths from Kansas and Nebraska to the Canadian prairies (May 18-19, 2021).

Weather synopsis

Since April 1, the 2021 growing season has been cooler and dryer than normal. The National Agroclimate Risk Report states that the most significant climate-related risk to agriculture is the dry conditions across the prairie region (access the Spring to April 27, 2021 report).

This past week (May 3-9, 2021), the average temperature across the prairies was 1.3 °C cooler than normal (Fig. 1). Similarly, the average 30-day temperature (April 10-May 9) was 1.7 °C less than climate normal values (Fig. 2). Temperatures have been warmest in southern Alberta (Table 1; Fig. 1-2).

**Figure 1.** Seven-day average temperature (°C) across the Canadian prairies for the period of May 3-9, 2021.

**Figure 2**. 30-day average temperature (°C) across the Canadian prairies for the period of April 10-May 9, 2021.

The growing degree day map (GDD) (Base 5 ºC, April 1-May 2, 2021) is provided below (Fig. 3) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 4.

**Figure 3**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 11, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure 4**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 11, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

At this early point in the growing season, cool temperatures pose the risk of frost but the differences between low and high temperatures can exert incredible stress on newly germinating plants in field crops. The lowest temperatures recorded ranged from <-59 to >-6 °C (Fig. 5) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <11 to >26 °C (Fig. 6). Wow, what an amazing range – spring is tough!

**Figure 5**. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 5-11, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

**Figure 6**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 5-11, 2021).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Seven-day cumulative rainfall indicates that below normal rain (86% of average) was reported for the prairies (Fig. 7). Over the past seven-days rain totals across most of Alberta and the extreme southwest region of Saskatchewan was 10-20 mm. The rest of the prairies received little or no rain. Rain (30-day accumulation) amounts have been less than average for most of the prairies (81% of average). Rainfall for April 10-May 9, 2021, has been greatest for southeastern Manitoba, southwestern Saskatchewan and across most of Alberta (Table 1; Fig. 8). Average growing season (April 1 to May 9) precipitation has been well below average for most of the prairies. The two large regions (Swift Current to Prince Albert to Vegreville and the western two-thirds of Manitoba) have had less than 40 % of normal precipitation.

**Figure 7**. Seven-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (May 3-9, 2021).

**Figure 8**. 30-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (April 10-May 9, 2021).

Access ALL the PPMN’s Wind Trajectory reports (Weekly and Daily).

Access Environment and Climate Change Canada’s weather radar mapping interface.

Potential of trajectories for monitoring insect movements

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. We receive two types of model output from ECCC: reverse trajectories and forward trajectories.

‘Reverse trajectories’ refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g. rain showers, etc.). Reverse trajectories are the best available estimate of the ”true” 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data.

‘Forward trajectories’ have a similar purpose; however, the modeling process begins at sites in USA & Mexico. The model output predicts the pathway of a trajectory. Again, of interest to us are the winds that eventually end up passing over the Prairies.

Access all the Historical Wind Trajectory Reports.

Weiss1, Vankosky1, Trudel2
1 Agriculture and Agri-Food Canada
2 Environment and Climate Change Canada

Weekly Wind Trajectory Report (released May 13)

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. Read a brief overview of this strategy plus the definitions and applications of both ‘Reverse’ and ‘Forward’ trajectories.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week, an increasing number of reverse trajectories have been moving north from Kansas and Nebraska (Fig. 1).

Figure 1. The average number (based on a 5-day running average) of reverse trajectories (RTs) that have
crossed the prairies for the period of May 1-13, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern Alberta (Fig. 2).

Figure 2. Total number of dates with reverse trajectories originating over the Pacific Northwest (PNW including Idaho, Oregon, and Washington) that have crossed the prairies between March 24 and May 13, 2021.

b. Mexico and southwest USA (Texas, California) – Since last week there have not been any trajectories that originated in these areas that have crossed the prairies.

c. Oklahoma and Texas – Since last week there have not been any trajectories originating in Oklahoma or Texas that have crossed the prairies.

d. Kansas and Nebraska – This week reverse trajectories were reported for Alberta (Andrew, Sedgewick), Saskatchewan (Gainsborough, Grenfell, Kindersley, Regina, Yorkton) and Manitoba (Brandon) (Fig. 3).

Figure 3. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the
prairies between March 24 and May 13, 2021.

2. FORWARD TRAJECTORIES (FT)
Forward trajectories, originating from Mexico and USA have crossed a number of prairie locations since May 1, 2021. Based on average totals (averaged across a five day period), the greatest number of forward trajectories were observed to originate between May 5 and 8 (blue bars) and entered the prairies between May 6-9 (Fig. 4).

Figure 4. The average number (based on a 5 day running average) of forward trajectories that have crossed the
prairies for the period of May 1- 13, 2021.

The following map presents the total number of dates (since March 24, 2021) with forward trajectories that have crossed the Canadian prairies (Fig. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

Figure 5. The total number of dates with forward trajectories, originating from various regions of the United States and Mexico, that crossed the prairies between March 24 and May 13, 2021.

Access a PDF version of the full WEEKLY report released May13, 2021.

Wind Trajectory Report for May 10

ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed one Saskatchewan location (Unity) and a number of Alberta locations including Lethbridge, Beiseker, Olds, Provost, Vegreville, Andrew, Grande Prairie, Rycroft and Fort Vermillion.

Access this DAILY one-page report to learn more. Albertans and Saskatchewanians please take note!

Areas highlighted green in this alert may receive incoming winds from the Pacific Northwest of the USA very shortly! Remember, host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

ALERT – Wind Trajectory Report for May 7

Environment and Climate Change Canada (ECCC) trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed a number of Alberta locations including Lethbridge, Beiseker, Olds, Manning, Rycroft, and Wanham.

Access this special one-page alert to learn more. Albertans please take note!

Action: Areas highlighted green in this alert may receive incoming winds from the Pacific Northwest of the USA very shortly so please deploy diamondback pheromone traps as soon as possible!

Weekly Wind Trajectory Report (released May 5)

Access a PDF version of the full report for May 5, 2021.

Weather synopsis

This past week (Aug 4-10, 2020) conditions were generally warm and dry. Weekly prairie temperatures were warmest across Manitoba and Saskatchewan (Fig. 1). Lower temperatures were observed across western and northwestern Alberta (Fig. 1). Though average 30-day (July 12 – August 10, 2020) temperatures continue to be cooler in Alberta than eastern Saskatchewan and Manitoba (Fig. 2), temperature anomalies (mean temperature difference from average; July 14-August 10, 2020) indicate that conditions have generally been warmer than average across most of Alberta as well as Parkland regions of Saskatchewan and Manitoba (Fig. 3).

**Figure 1.** Observed average temperatures across the Canadian prairies the past seven days (August 4-10, 2020).

**Figure 2.** Observed average temperatures across the Canadian prairies the past 30 days (July 12-August 10, 2020).

**Figure 3.** Mean temperature difference from Normal the past 30 days (July 14-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Regions in southeastern central and southern Saskatchewan and across southern Manitoba have reported temperatures that have been up to 2 °C cooler than average. Based on growing season temperatures (April 1-August 10, 2020) temperatures were warmest across the southern prairies (Fig. 4). Based on growing season temperature deviations (observed temperatures compared with climate normal temperatures), below average temperatures have been observed across central and western regions of Saskatchewan and central regions of Alberta (Fig. 5). Across southern Alberta and most of Manitoba, temperatures have generally been above average. (Fig. 5)

**Figure 4.** Observed average temperatures across the Canadian prairies for the growing season (April 1-August 10, 2020).

**Figure 5.** Observed difference from average temperatures across the Canadian prairies for the growing season (April 1-August 10, 2020).

Most areas reported 7-day cumulative rainfall amounts that were less than 10 mm (Fig. 6). Cumulative 30-day rainfall was lowest across a large area ranging across southern Alberta as well as central and western regions of Saskatchewan (Fig. 7). Growing season rainfall (percent of average) is highly variable across the prairies (Fig. 8). Rainfall has been below normal across most of Saskatchewan as well as southern Alberta, and the Peace River region (Fig. 8).

**Figure 6**. Observed cumulative precipitation across the Canadian prairies the past seven days (August 4-10, 2020).

**Figure 7**. Observed cumulative precipitation across the Canadian prairies the past 30 days (July 12-August 10, 2020).

**Figure 8.** Percent of average precipitation for the growing season (April 1-August 10, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-August 9, 2020) is below (Fig. 9) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 10.

**Figure 9**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-August 9, 2020).

**Figure 10**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-August 9, 2020).

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <17 to >34 °C (Fig. 11) while the lowest temperatures ranged from <-1 to >13 °C (Fig. 12). So far this growing season (as of August 12, 2020), the number of days above 25 °C ranges from 0-10 days in the west (to west of Calgary, west and north of central Alberta and extending into the south and west of the Peace River region) but extends up to 51-60 days in southern Manitoba (Fig. 13).

**Figure 11**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 12**. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 13**. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Weather synopsis

This past week (July 28 to August 3, 2020) prairie temperatures were warmest in southeastern Alberta and southwestern Saskatchewan and coolest in southern Manitoba and the Peace River region of Alberta and British Columbia (Fig. 1). Temperatures in the past week represent a switch from previous weeks, where it was warmer in Manitoba than in Alberta. Average 30-day temperatures (July 5 to August 3, 2020) continue to be cooler across most of Alberta than observed in eastern Saskatchewan and Manitoba (Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Fig. 2).

**Figure 1.** Observed average temperatures across the Canadian prairies the past seven days (July 28-August 3, 2020).

**Figure 2.** Observed average temperatures across the Canadian prairies the past 30 days (July 5-August 3, 2020).

**Figure 3**. Mean temperature difference from Normal the past 30 days (July 1-31, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta, Saskatchewan and Manitoba (Fig. 4). Cumulative 30-day rainfall was lowest across a large area ranging from southwest Saskatchewan to Saskatoon (Fig. 5). Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba and above normal across most of Alberta (Fig. 6).

**Figure 4**. Observed cumulative precipitation across the Canadian prairies the past seven days (July 28-August 5, 2020).

**Figure 5**. Observed cumulative precipitation across the Canadian prairies the past 30 days (July 5-August 3, 2020).

**Figure 6.** Percent of average precipitation for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (04Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-August 3, 2020) is below (Fig. 7) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 3, 2020) is shown in Figure 8.

**Figure 7**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 8**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <24 to >32 °C (Fig. 9). So far this growing season (as of August 6, 2020), the number of days above 25°C ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 51-60 days in southern Manitoba (Fig. 10).

**Figure 9**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 10**. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-August 5, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Weather synopsis

An abbreviated synopsis of the past week is provided below. Recent warm weather across the Canadian prairies helped crop development this past week

The growing degree day map (GDD) (Base 5 ºC, April 1-July 27, 2020) is below (Fig. 1) while the growing degree day map (GDD) (Base 10 ºC, April 1-July 27, 2020) is shown in Figure 2.

**Figure 1**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 27, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 2**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-July 27, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <22 to >34 °C (Fig. 3). So far this growing season (up to July 29, 2020), the number of days above 25 ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 41-50 days in southern Manitoba (Fig. 4).

**Figure 3**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 4**. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta, Saskatchewan, and Manitoba with the exception of around Regina south to the American border, and southwest Manitoba west into the southeast corner of Saskatchewan (Fig. 5). Cumulative 30-day (Fig. 6) and rainfall for the growing season (April 1-July 29, 2020; Fig. 7) are below.

**Figure 5**. Observed cumulative precipitation across the Canadian prairies the past seven days (as of July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 6**. Observed cumulative precipitation across the Canadian prairies the past 30 days (as of July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 7**. Observed cumulative precipitation across the Canadian prairies for the growing season (as of July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Weather synopsis

This past week (July 13-19, 2020) prairie temperatures were warmest in Manitoba and eastern Saskatchewan (Table 1; Fig. 1). Average 7-day temperatures continue to be warmest across Manitoba and eastern Saskatchewan and coolest across most of Alberta(Table 1; Fig. 1).

**Figure 1.** Observed average temperatures across the Canadian prairies the past seven days (July 13-19, 2020).

Average 30-day (June 20-July 19, 2020) temperatures continued to be cooler in Alberta than eastern Saskatchewan and Manitoba (Table 2; Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan(Table 2; Fig. 2). Based on growing season temperatures (April 1 – July 19, 2020), conditions continue to be warmest for southern locations (Table 3).

**Figure 2.** Observed average temperatures across the Canadian prairies the past 30 days (June 20-July 19, 2020).

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta and Saskatchewan. Cumulative 30-day rainfall was lowest across a large area ranging from southwest Saskatchewan to Saskatoon. Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba.

**Figure 4**. Observed cumulative precipitation across the Canadian prairies the past seven days (July 16-19, 2020).

**Figure 5**. Observed cumulative precipitation across the Canadian prairies the past 30 days (June 20-July 19, 2020).

**Figure 6.** Percent of average precipitation for the growing season (April 1-July 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (21Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-July 13, 2020) is below (Fig. 7) while the growing degree day map (GDD) (Base 10 ºC, April 1-July 13, 2020) is shown in Figure 8.

**Figure 7**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 22, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 8**. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-July 22, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <19 to >32 °C (Fig. 9). So far this growing season (up to July 22, 2020), the number of days above 25 ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 41-50 days in southern Manitoba (Fig. 10).

**Figure 9**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

**Figure 10**. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-July 22, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Weather synopsis

The 2020 growing season, April 1 – July 12, 2020, has been cooler and wetter than normal across many locations in Alberta and Saskatchewan. Conditions in Manitoba have been warmer and dryer than normal. This past week (July 6-12, 2020) prairie temperatures were warmest in Manitoba and eastern Saskatchewan (Table 1; Fig. 1). Average 7-day temperatures continue to be warmest across Manitoba and eastern Saskatchewan and coolest across most of Alberta (Table 1; Fig. 1).

**Figure 1.** Observed average temperatures across the Canadian prairies the past seven days (July 6-12, 2020).

Average 30-day (June 13-July 12, 2020) temperatures continue to be cooler in Alberta than in southern Saskatchewan and Manitoba (Table 2; Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Fig. 2). Temperature anomalies indicate that temperatures have been below normal across most of Alberta and Saskatchewan and were 0 to 2 °C warmer than average across eastern Saskatchewan and southern Manitoba (Table 2; Fig. 3). Based on growing season temperatures (April 1 – July 12, 2020), conditions have been warmest for southern locations (Table 3).

**Figure 2.** Observed average temperatures across the Canadian prairies the past 30 days (June 13-July 12, 2020).

**Figure 3**. Mean temperature difference from Normal the past 30 days (June 16-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta and across most of Manitoba (Table 1 Fig. 4). Lethbridge reported 4.2 mm and Winnipeg reported 1.4 mm (Table 1). Cumulative 30 day rainfall continued to be greatest across central regions of Alberta (Table 2; Fig. 5). Rainfall amounts were lowest across southern regions of the prairies (Table 2; Fig. 5).

**Figure 4**. Observed cumulative precipitation across the Canadian prairies the past seven days (July 6-12, 2020).

Total 30-day rainfall at Brandon, Winnipeg and Swift Current was less than 100 mm (Table 2; Fig. 5). Lethbridge has reported 122.3 mm (261% of normal) in the past 30 days (Table 2). Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba.

**Figure 5**. Observed cumulative precipitation across the Canadian prairies the past 30 days (June 13-July 12, 2020).

**Figure 6.** Percent of average precipitation for the growing season (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (14Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-July 13, 2020) is below (Fig. 7):

**Figure 7**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 10 ºC, April 1-July 13, 2020) is below (Fig. 8):

**Figure** 8. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed the past seven days ranged from <15 to >33 °C in the map below (Fig. 9).

**Figure 9**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Weather synopsis

This week, June 29-July 5, 2020, prairie temperatures were warmest in Manitoba and eastern Saskatchewan and seven day cumulative rainfall varied across the prairies (Table 1). Average 7-day temperatures continue to be warmest across Manitoba and eastern Saskatchewan and coolest across most of Alberta (Fig. 1). The weekly average temperature at Winnipeg (24.5 °C) was 6.6 °C warmer than the long term average value and was 10.9 °C warmer than the 7-day observed temperature at Grande Prairie (Table 1; Fig. 1). The average weekly temperature for Lethbridge was 13.8 °C and 2.3 °C cooler than normal (Table 1).

**Figure 1.** Observed average temperatures across the Canadian prairies the past seven days (June 29-July 5, 2020).

Average 30-day (June 6-July 5, 2020) temperatures continue to be cooler in Alberta than southern Saskatchewan and Manitoba (Table 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Table 2; Fig. 2). June temperature anomalies indicate that temperatures have been below normal across most of Alberta and Saskatchewan and were 0 to 2 °C warmer than average across southeastern Saskatchewan and southern Manitoba (Table 2; Fig. 3). Based on growing season temperatures (April 1 – July 5, 2020), conditions were warmest for southern locations (Table 3).

**Figure 2.** Observed average temperatures across the Canadian prairies the past 30 days (June 6-July 5, 2020).

**Figure 3**. Mean temperature difference from Normal for the month of June 2020.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (05Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across western regions of Saskatchewan (Table 1; Fig. 4). Lethbridge reported 69.4 mm. Cumulative 30-day rainfall continued to be greatest across central regions of Alberta (Table 2; Fig. 5). Rainfall amounts were lowest across the most of Saskatchewan.

**Figure** 4. Observed cumulative precipitation across the Canadian prairies the past seven days (June 29-July 5, 2020).

Total 30-day rainfall at Saskatoon, Lethbridge, Lacombe and Grande Prairie exceeded 100 mm (Table 2; Fig. 5). Saskatoon has reported 156.6 mm (277% of normal) in the past 30 days (Table 2). Growing season rainfall (percent of average) is below normal southern Saskatchewan and most of Manitoba. Rainfall amounts are above average across central regions of Saskatchewan and across Alberta.

**Figure 5**. Observed cumulative precipitation across the Canadian prairies the past 30 days (June 6-July 5, 2020).

**Figure 6.** Percent of average precipitation for the growing season (April 1-July 5, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (05Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-July 6, 2020) is below (Fig. 7):

**Figure 7**. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 6, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed the past seven days ranged from <15 to >33 °C in the map below (Fig. 8).

**Figure 8**. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 8, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk10 (released June 22, 2020).

Wind Trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk08 (released June 15, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk07 (released June 8, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk06 (released June 1, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk05 (released May 25, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk04 (released May 18, 2020).

→ Read the DAILY Wind Trjectory Reports for Wk04 (released May 20 and May 21).

Wind trajectories

Access the 2020 Wind Trajectory Reportsfor the first WEEKLY REPORT (11 May 2020).

New – Review the DAILY REPORT (released 15May2020).

Wind trajectories

Find the first WEEKLY report (available 11 May 2020).

Wind trajectories

Data not available this week.

Weather synopsis

Temperatures this week, June 18-24, 2019, were similar to last week. Over the past seven days temperatures were cooler than normal. The warmest temperatures were observed across MB while temperatures were cooler in western SK and across AB (Fig. 1). The is a complete reversal to last week.

Average 30 day temperatures were warmest across southern MB and SK (Fig. 2). Cooler temperatures were reported across eastern and northern AB. The mean temperature differences from normal (May 21 – June 17, 2019) have been zero to two °C warmer than normal for AB and SK while temperatures in MB have been zero to two °C cooler than normal (Fig. 3).

Figure 3. Mean temperature difference from Normal across the Canadian prairies over the past 30 days (to June 17, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (25Jun2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Growing season temperatures (April 1-June 24, 2019) have been warmest across the southern prairies (Fig. 4). The warmest growing season temperatures have been reported for southern AB and an area south of Winnipeg MB. Across the prairies, the average growing season temperature has been 1.2 °C below normal.

This past week significant rainfall amounts were reported for most of SK and across central regions of AB (Fig. 5). Across the prairies, rainfall amounts for the past 30 days (May 26 – June 24, 2019) have been near normal (Fig. 6). The Edmonton region has been the wettest.

The growing degree day map (GDD) (Base 5 ºC, April 1-June 24, 2019) is below (Fig. 9):

Figure 9. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-June 24 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (25Jun2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The growing degree day map (GDD) (Base 10 ºC, April 1-June 24, 2019) is below (Fig. 10):

Figure 10. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-June 24, 2019).Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (25Jun2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The lowest temperatures (°C) observed the past seven days ranged from about 11 to 0 °C in the map below (Fig. 11).

Figure 11. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (to June 24, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (25Jun2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The highest temperatures (°C) observed the past seven days ranged from about 16 to at least 27 °C in the map below (Fig. 12).

Figure 12. Highest temperatures (°C) observed across the Canadian prairies the past seven days (to June 24, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (24Jun2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Drought Watch Maps for the growing season.