It's the Coldest Airmass in 5 Years and Significant Snow is on the Way!

Good morning…

The much advertised cold is now here with the long-wave trough firmly established over the East and the Polar Vortex displaced over Quebec. This will allow bitterly cold air to drain southward over the several days, and in the near term this will come with quite a bit of wind as well. Wind gusts to 30 mph tomorrow will produce wind chill values in the single digits for much of the day, perhaps even below zero in the morning. Highs will be no better than the mid 20s through Thursday, but precipitation is not expected through that time frame (save a stray flurry today).

The pattern changes a bit Thursday night into Friday as the long-wave trough relaxes and a shortwave disturbance dips into the Plains. As this feature amplifies and heads eastward, low pressure over the Upper Midwest will fade away with a second area of low pressure expected to take shape over the Southern Plains or Lower Mississippi Valley. At least that is the current thinking… some guidance suggests that the southern low doesn't materialize at all, instead keying on the weaker low as it moves across the Upper Midwest and into the Ohio Valley. Regardless, precipitation is expected to develop sometime on Friday, and at this juncture the precipitation type looks to be snow.

That said, there remains some uncertainty with the eventual storm track. While the bulk of the model guidance continues to advertise the southern low fading as it moves into the Appalachians with a coastal low developing to the east… but the question becomes how far north/east does the primary low make it before the coastal low develops and takes over? It's not out of the question, if the primary low tracks into northwestern Pennsylvania, that a warm nose pushes overhead and allows some sleet to mix in… but right now that is not supported by the modeling. Of course, if the low ends up even farther south than we currently believe, or if the southern low fails to materialize, then the snow will be an insignificant event.

As it currently stands, things look good for at least some snow, and there is a decent shot at moderate accumulations (several inches). In any event, remaining cold for Saturday as the trough over the East deepens, and then gradually pushing back closer to "normal" early next week as the trough lifts out (at least temporarily).

Have a great day!