Severe weather threat for parts of the Prairies
Atmospheric conditions will be ripe for the formations of severe thunderstorms across parts of the Prairies through this evening and again on Tuesday.
A fairly strong disturbance riding along the jet stream will interact with warm, humid air surging up from the south and southeast creating a favorable setup for severe thunderstorms.
Strong to severe thunderstorms have already formed over south-central Saskatchewan as of late Monday morning local time and will just get stronger as they re-form farther south and track toward the northeast.
The greatest threat for severe thunderstorms through this evening will be from south-central Saskatchewan through eastern Saskatchewan and into extreme western Manitoba.
The strongest storms will contain large, damaging hail, wind gusts in excess of 90 kmh and perhaps a tornado.
By Tuesday afternoon, the leading edge of cooler air (cold front) will interact with this disturbance and we expect the thunderstorms to rebuild over southeastern Manitoba and then spread quickly into northwestern Ontario later in the day and into the evening with similar results. (see map below).
Eastern heat wave
Very strong, stagnant area of high pressure aloft will cover the eastern half of the U.S. and into eastern Canada through midweek.
Daytime temperatures will certainly be hot, but not a lot of records are expected to fall as the source of this high pressure dome was the western Atlantic (Bermuda) and not the western U.S. However, the fact this this originated over the western Atlantic means that the humidity will be very high, making it feel at least 3 to 6 degrees Celsius higher than what the actual temperature is.
In addition to the heat and humidity, the high pressure dome will create poor air quality for many as the pollutants remain trapped near the surface thanks to the warm layer aloft and the lack of wind.
The ridge of high pressure will finally begin to break down late in the week and this will lead to an increase in thunderstorms across eastern Canada Thursday and Friday with the potential for severe weather as the winds aloft begin to steadily increase.
Relief from the high humidity should finally come later Saturday and Sunday as the cold front pushes south of the region.
Another stretch of dry weather for parts of eastern Canada into next week.
A warm first half of summer for a majority of Canada.
Fast, west-to-east jet stream pattern across southern Canada into next week.
Clues to the long range over the next several weeks across North America.
Potential for significant rainfall over southwestern Alberta late this week into the early weekend.
A strong, upper-level storm system will bring significant rain, severe thunderstorms and much cooler air to parts of western and central Canada into early next week.