An upper ridge building into the eastern Prairies will bring the heat back, sending the temperatures back towards the 30°C mark.
Conditions will be beautiful – and very welcome to those sick of all the rain this summer – with plenty of sunshine through the second half of the week. A low pressure system will drag a trough across Southern Manitoba late Thursday into Friday morning, which will likely spark off another round of thunderstorm activity through the region.
Monday: Start the Warm-Up
Today will be a beautiful day with light winds, mainly clear skies and a high near 24 or 25°C. The “significant” weather event of the day will be the passage of a ridge of high pressure which will be marked by a gradual transition of the winds from northerly to southerly, setting up the return flow of heat for the remainder of the week.
Thursday: Hot with Severe Thunderstorm Risk
UPDATE: Updated thunderstorm discussion is available in the comments, right here.
Things become more interesting on Thursday as a low pressure system tracking along the NWT/Nunavut border drags a secondary frontal wave across the southern Prairies. Temperatures will soar into the high 20’s across southern Manitoba on Thursday with a southerly wind at around 30km/h. Humidity will also build ahead of the approaching system with dewpoints rising into the mid-to-high teens by the end of the day.
Clouds will likely begin building into the Red River Valley through the afternoon, but no precipitation is expected until the overnight hours.
At this point, it’s too early to go into specifics, but even already it looks like there’s a slight chance of severe thunderstorms over western Manitoba on Thursday evening with all modes of severe weather possible.[1] The threat will continue eastwards overnight as the storms become elevated and continue on through the night. The southward extent of the storm activity is unclear now, but it seems that for Winnipeg and the Red River Valley, there’s a decent chance we’ll see thunderstorms overnight with greater likelihood northwards through the Interlake. These storms will also have the risk to be severe with large hail and strong winds.
Pleasant Friday
Friday will find Winnipeg on the back-side of the system moving across the Prairies and will see quite pleasant conditions with a ridge of high pressure building in from the west. Temperatures will be pleasantly warm with highs near the mid-to-upper 20’s and light winds. Temperatures will drop into the mid-teens overnight.
Long-Range
Bad news everyone. Brace for the return of below normal. A prominent long-wave ridge is forecast to build up over western North America with a resultant long-wave trough developing over Hudson Bay into the Great Lakes.
This will set up a persistent northwesterly flow which will likely produce slightly below-normal temperatures.[2] The heat and main storm track will shunt southwards into the Northern & Central Plains, leaving us with just the odd system sliding southeastwards in the northwesterly flow.
