The first part of last week’s forecast played out pretty much as expected, but things fell apart a little bit toward the end of the forecast period. The expected ridge of high pressure did build to our west, and we did see mild air move in over the weekend, just not to the initial extent that the weather models predicted. The upper ridge ended up not being as strong as originally forecast, and while above-freezing temperatures did try to push in last weekend, conditions kept the warm air aloft with cool air trapped at the surface.
For this forecast period, it looks like we are going to have our second cold snap of this winter. The overall pattern that’s forecast to develop has a large trough of low pressure setting up over eastern North America, with a ridge of high pressure to our west. This is in response to the polar vortex breaking down and splitting into two distinct areas. This will place us in a north-to-northwesterly flow and will open us up to invasions of cold arctic air. The first real push of arctic air will move in Wednesday as the first of several arctic highs drops down from the north. Expect daytime highs to fall into the -20 C range with overnight lows in the low -20s to around -30 C.
This initial shot of cold air will be reinforced over the weekend as a second larger area of arctic high pressure slides through our region. This high may bring the coldest temperatures of the season, with daytime highs only expected to make it in the -22 C range and overnight lows around -32 C. On the bright side, we should see plenty of sunshine along with fairly light winds.
The weather models then show a third arctic high moving in from the north early next week that will keep our temperatures running near the bottom end of the usual temperature range for this time of the year. We may see some clouds and possibly a few flurries on Tuesday as a weak area of low pressure skirts through ahead of the high. Looking a little further ahead, the weather models show a break in the cold snap later next week, with a return to more seasonable temperatures along with the chance of some measurable snow.
Usual temperature range for this period: Highs, -23 to -6 C; lows, -34 to -16 C.