The system that brought severe thunderstorms to the Interlake and southwestern Manitoba will bring a huge shift in the weather pattern over the next couple days as it moves over Hudson Bay and stalls, setting up an extremely abnormal pattern for July that will see cool Arctic air spilling southwards unhindered. In the process another cold front will slump through Southern Manitoba bringing another day of unsettled weather on Saturday.
Today will be a fairly nice day all things considered. Winds will be out of the west to northwest at 20-30km/h as temperatures climb into the mid-20’s. No precipitation is expected today. Temperatures will remain somewhat mild tonight, dropping only into the mid-teens.
Saturday will bring another bout of unsettled weather as a cold front slumps southward through the Interlake into the Red River Valley. Instability will build throughout the morning with showers and thunderstorms developing along the cold front by midday through the Interlake. The activity will slump southwards through the day, with showers and thunderstorms likely through the Red River Valley, particularly the northern & eastern halves.
Saturday is also the Morden triathlon. Conditions will be fairly pleasant, with temperatures around 15°C in early in the morning warming to around 24°C by lunch time. Winds will start the morning out of the southwest at around 15km/h and increase to 30km/h or so by midday. There will be a very slight chance of a shower beginning late in the morning and through the early afternoon, although precipitation is most likely to hold off until the cold front passes through the region late in the afternoon.
Sunday will mark our first day in a very unseasonably cold air mass. Most of Southern Manitoba will see a northwesterly wind at 30-40km/h. The high will only be around 19°C – some 7 or 8°C below normal. There will be a chance of showers on Sunday night while temperatures dip below the 10°C mark.
How Long Will The Cold Last?
There’s no question the incoming cold air is hugely abnormal for this time of year: 1000-500mb thicknesses[1] are expected to fall below 546dm through Northwestern Ontario into MN/WI/MI. These values are more appropriate for late in the fall than in the middle of July. Depending on exactly how deep this cold trough becomes, record low thicknesses for July may be set in those regions.
Here in Manitoba, we’ll avoid the core of the coldest air, but we’ll still be well below normal. Fortunately this setup doesn’t appear to want to remain locked in for very long. The cold trough is expected to push off to the east fairly quickly with warm air pushing back into the province by mid-week.
As the warm air pushes in, it actually looks like we may finally move into a warm and dry summer-like pattern. All long-range weather models are showing a nice dry spell developing from mid-week into next, with temperatures gradually warming up towards the 30°C by the end of the week!
- The 1000-500mb thickness is literally the distance between those two levels in the atmosphere. The colder the column of air is, the lower the thickness while the warmer the column is, the higher the thickness is. ↩
