Additional threats for severe thunderstorms the rest of this week
The thunderstorms that erupted over southern and central Saskatchewan yesterday likely spawned a few tornadoes as indicated by the severe weather report from Environment Canada below....
Another scorcher Wednesday......
The map below shows how hot it will actually feel Wednesday afternoon when you factor in the sun, wind speed and humidity. Certainly not a pretty site with AccuWeather.com Realfeel temperatures peaking in the 35 to 41 degree C. range from Montreal to Toronto and Windsor. Stay cool!
I do believe that this week's combination of heat/humidity will be the worst of the summer for eastern Canada.
Looking ahead, a rapidly moving front will likely trigger a broken line of strong to severe thunderstorms over southern/eastern Quebec and northern New Brunswick Wednesday afternoon and evening. The greatest threat for severe weather in the St. Lawrence River Valley will likely be in the 3pm to 6pm time frame. The strongest storms could produce hail and wind gusts in excess of 90 kmh.
By the end of the week a second, stronger front will clash with the heat and humidity, triggering widespread thunderstorms that could be quite severe.
The timing of this front is still up in the air and I may be a little fast with the arrival of severe thunderstorms for Friday.
Anyway, I expect severe thunderstorms to break out Friday afternoon from northwest of Quebec City to near Pembroke to the North Bay region and progress south and east from there through Friday evening.
The combination of a strengthening jet stream, high humidity and heat will create a favorable setup for damaging thunderstorms later Friday and again on Saturday. Straight-line wind damage will be the greatest threat.
The storms will also produce intense rainfall, but the good news is that they will be moving at a steady clip, reducing the threat for significant flooding.
At this point, I believe the time window for severe thunderstorms from Windsor to Toronto to Montreal will be after 6pm Friday. Again, I can see how this front ends up slower, and if that is the case the storms would not be quite as strong since they would be moving through Friday overnight and early Saturday.
By Saturday, the main risk for severe thunderstorms shifts to New Brunswick and then southeast through New England/NY/PA/OH and into the Niagara region.
I will keep you updated through the week with any changes in thinking in regards to this threat.
Widespread snow across western Canada into Friday followed by a nasty shot of Arctic air.
Update on the snowfall map for the East.
Update on snowstorms.
An interpretation of the latest ECMWF weekly long-range forecast output...
Clipper-like storm system will bring light snow to eastern Canada into tonight followed by another round of locally heavy lake-effect snow.
More about the lake-effect snow and upcoming weather pattern.