We've escaped most of the cold weather so far this season, but we're about to make up for some lost time as a significant cold blast comes our way. There's a deep reservoir of bitterly cold air from Alaska into Canada that is just waiting to spill south. A strong cold front will tap into that air mass and allow it to spread down into the Plains and Midwest by Sunday. It'll be the coldest air of the season thus far and will be a shock to our systems after record warmth in the past week.
Before the temperature tumble, our weather will remain unseasonably mild. A weak cold front sliding through the region on Friday will keep clouds and drizzle in place, but temperatures will remain in the cool-to-mild category. Southerly winds return Saturday, bringing up those readings into the 60s area-wide. It will be rather pleasant for all of the holiday parades around Green Country in fact. The sharp cool-down begins Sunday as the Arctic cold front races southeast across the Plains. Temperatures will be at their warmest early Sunday morning before brisk northerly winds usher in the cold air. Instead of warming up in the afternoon, temperatures will fall into the upper 30s. By dusk, those readings will continue their nosedive well into the 20s. While that in itself is chilly, the wind will make it that much colder. Wind chill values will be in the teens and 20s by Monday morning. Needless to say, Old Man Winter is paying us a visit.
The one factor that is keeping us from dealing with even colder temperatures is the lack of snow cover across the country. Only 10% of the Lower 48 has any snow on the ground, which is quite low for December (see the map above). Cold air rushing from the Polar Regions will stay colder longer if it travels over a cold snowpack. As this Arctic air mass encounters a landscape barren of snow, it will modify and lose its edge. Snow cover has a big impact on regional temperatures. Fortunately for us, we won't be seeing a winter chill at its worst.
Speaking of snow, many people are wondering if we'll see any flakes flying with this system. After all – it is December. There is a chance of flurries late in the day, Sunday, but moisture will be scoured out quickly behind this system. So, our window for any light snow is narrow and the probability for accumulation is almost zero. Just don't be surprised if you see a few flakes. The atmosphere will certainly be cold enough for precipitation of the frozen variety behind the cold front. The moisture will be the missing component.
We won't stay in the deep freeze for very long. As early as Tuesday, temperatures begin to warm with a return to southerly winds. We won't reach the same levels as last weekend, but by Thursday, our temperatures will be back in the above-normal category. Another chance of rain followed by another cool-down appears likely toward the end of next week.
Grab that coat – it's finally about to feel like winter around here! Be sure to follow me on Twitter: @GroganontheGO and "like" me on Facebook!