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).

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 May 27, 2021.

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).

Figure 4. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed
the prairies between March 24 and May 27, 2021.

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.

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed
the prairies between March 24 and May 27, 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 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.

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).

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 20, 2021.

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.

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).

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.

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)

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.

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