It looks like the transition from a summer to a fall weather pattern has begun. This was evident in last week’s forecast, which didn’t quite play out as expected. We did see a rather strong area of low pressure move through our region last weekend, but the forecast timing and track of the system was a little off. Seasons such as spring and fall, where the atmosphere starts to undergo a pattern shift, are the most difficult periods to forecast.
That said, this forecast period will begin with cool high pressure slowly sliding to our east. This will result in sunny to partly cloudy skies on Wednesday with daytime highs in the low 20s and overnight lows around the 10 C mark. The weather models then show an area of low pressure developing over northern Alberta, tracking eastward into northern Manitoba by Friday. We will see a fairly strong southerly flow develop ahead of this low, which will help to boost temperatures into the mid- to upper 20s Thursday and Friday. The low will drag a cold front across southern and central Manitoba sometime on Friday, resulting in increasing clouds with a good chance of showers and thundershowers.
We will see a brief cool-down behind the cold front, but temperatures look to rebound nicely over the long weekend as an upper ridge builds across our region. We should expect mainly sunny skies on Saturday and Sunday with daytime highs by Sunday expected to be in the 25 to 28 C range. This upper ridge is forecast to collapse on Monday as another area of low pressure forms over Alberta and quickly moves eastward. This low will bring increasing clouds along with showers and thundershowers on Monday. Temperatures will remain warm, but just how warm will depend on cloud cover and precipitation.
Behind the low, the weather models show an arctic high dropping southward, bringing clearing skies and cool temperatures for the start of school. The current forecast highs for next Wednesday are around 14 C, with overnight lows dropping into the 2 to 5 C range. This means there is a small chance some areas could see some light frost.
Usual temperature range for this period: Highs, 17 to 27 C; lows, 5 to 13 C.