It's July and thunderstorms are becoming a common theme each day as the average temperature is at its peak, while North Atlantic sea surface and lake surface temperatures continue to average warmer than normal.
The leading edge of cooler and much less humid air will sweep across Ontario through tonight then Quebec Wednesday morning. The front will slow its forward speed later Wednesday as it encounters the strong Atlantic high pressure ridge. Warm, humid air ahead of the front on Wednesday should lead to another round of showers across the Maritimes with embedded thunderstorms as well.
Farther west, an Alberta clipper-like storm will push across the Prairies and will trigger some thunderstorms from Saskatchewan to northwestern Ontario. The greatest threat of strong thunderstorms will be across southeastern Manitoba and just into Ontario during the afternoon and early evening.
There will also be a second area of thunderstorms over southwestern Alberta due to a weak upslope flow and afternoon instability. The greatest threat from these storms will be localized flash flooding (due to slow movement) and cloud to ground lightning. I heard that there were four houses that were struck by lightning last night in the Calgary area.
Cooldown for BC late in the week
The hot weather that has dominated across interior BC will finally get pushed out by a stronger Pacific trough late this week.
This system will spread much cooler, Pacific air into the region starting Friday and likely continuing into Monday.
Unfortunately, it does not look like there will be little or no rainfall from this system for southwestern BC. Vancouver has not had any measurable rain in a month. Most of the showers and thunderstorms with this system will likely form over the Rockies then transfer over into Alberta over the weekend.
Update on major eastern storm into the weekend.
Major storm system will bring heavy rain, followed by strong winds, falling temperatures and possible high elevation snow into this weekend over the East.
The 2016/2017 winter forecast for Canada has a snowy look for many.
Early November not looking all that cold, but that could change quickly later in the month.
Update on the two major storm systems approaching the West coast for late this week.
Two significant storms will bring widespread, heavy rain and strong winds to southwest British Columbia later Thursday and again late Saturday.