The only issue with last week’s forecast was underestimating the magnitude of the warm air last Friday and Saturday, as temperatures in most locations across southern and central Manitoba managed to rise several degrees above 0 C. Of particular interest was just how warm some of the overnight lows were, with temperatures actually rising overnight before cooling off toward morning.
This forecast period will begin with what looks to be the last of the unseasonably mild weather, as an area of low pressure moves in from the northwest on Wednesday. This low will flatten the warm ridge of high pressure and bring with it a chance of showers at first, followed by a few flurries or some light snow as the low drags a cold front through our region. Thursday should see a mix of sun and clouds along with fairly mild temperatures as a second stronger area of low pressure begins to push eastward from the Pacific. We should see increasing clouds on Friday as the weather models track this system through the Interlake over the weekend. If the low keeps this track, most of the snowfall will take place across north-central and far eastern regions, with a few centimetres of accumulation expected.
Arctic high pressure is then forecast to build in from the north on Sunday and Monday, bringing with it sunny skies and seasonable temperatures. Expect daytime highs to be in the -12 C range by Christmas Eve, with overnight lows in the -18 to -22 C range. On Christmas Day, the weather models show a weak area of low pressure tracking through the Dakotas that will bring some clouds and some flurries to extreme southern regions.
Looking further ahead, it looks like another area of arctic high pressure will slip by to our northeast during the second half of next week, bringing with it plenty of sunshine and seasonable temperatures. Currently, it looks like the coldest air will stay well to our north. We then have to keep our eyes on a system forecast to develop late next week, which could bring us our first significant snowfall in quite a while.
Usual temperature range for this period: Highs, -20 to -4 C; lows, -29 to -12 C.