We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):
(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.
(ii) ‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest are the winds that eventually end up passing over the Prairies.
Current Data
The number of Reverse Trajectories (RTs), crossing the prairies in May 2018, was lower than the long term average (2007 - 2017). The total number of incoming trajectories (sum of Pacific Northwest and southwest USA/Mexico) for 2018 was less than similar values for 2017 and 2007 - 2017. Based on RTs by region, the number of RTs from the Pacific Northwest (PNW) was less than 2007 - 2017 and 2017. To date, the RTs originating in the southwest USA/Mexico in 2018, have been greater in number than in 2017 and less than the long term average (Fig. 1).
 |
| Figure 1. Total number of reverse trajectories by geographic region (Pacific Northwest and Mexico and the southwest USA) for May 2018. |
Weather forecasts (7 day):