Frigid again today; fluffy snow tonight into Thursday

After frigid Canadian air departs our part of the world, it often streams southeastward across the Great Lakes. The cold air picks up moisture from the unfrozen lakes, easily becomes saturated, and can dump large amounts of snow downstream.

These lake effect snowstorms are most common in Michigan (Upper and Lower) and Upstate New York, where hilly terrain enhances the snowfall.

Sometimes the northwestern corner of Pennsylvania where that state reaches Lake Erie is impacted if the flow off the lake is in just the right direction. Erie, Penn., right on the shore of the lake, has been in the snowy bull's-eye the past few days.

Their official snowfall measurements were 34 inches on Christmas Day and 26.5 inches yesterday. That is a two-day total in excess of 60 inches. Snow continues to fall there this Wednesday morning and a lake effect snow warning remains in effect.

Cold high pressure

The center of the arctic high pressure is centered right over our area Wednesday. That means that we will enjoy yet another day of very cold temperatures. But it also means that the pressure gradient has relaxed so winds will be quite light for a change.

Temperatures around the state at 7 a.m. Wednesday include 8 below in the Twin Cities, 15 below in Rochester and New Ulm, 24 below in Mora and Little Falls, 32 below in Bemidji, 33 below in Ely and an attention-getting 35 below up in Big Fork.

High temperatures this afternoon will be mainly in the single digits below zero in northern parts of the state and singles above zero in the south. The Twin Cities should have a high around 3 above Wednesday afternoon with a light west wind that will become southerly this afternoon.

Fluffy snow on its way

A whitening of snow will come our way tonight and for Thursday. Snow should break out in southwestern Minnesota Wednesday evening and spread northeastward across the state overnight. Snow is likely to reach the Twin Cities around midnight and depart most of the state eastbound by around noon on Thursday.

This will be a dry, powdery snow of low density, so even with little water content in the cold air it should fluff up to 2 or 3 inches over most of the area. Parts of central Minnesota, maybe from St. Cloud to the Brainerd area, could get a bit more than 3 inches. The far northern parts of the state might struggle to get even a whole inch.

Snow will be tracking out of Minnesota and across the Great Lakes area on Thursday. Forecast models continue to predict some freezing rain likely for southeastern Georgia and coastal South Carolina late on Thursday.

Back in the deep freeze

Thursday's little weather-maker will temper the cold weather for a day or so. Then the arctic chill will begin to return on Friday.

The upcoming New Year's weekend looks as though it will be even colder than was Christmas weekend. Low temperatures Saturday, Sunday and probably Monday should range from the 30s below zero in the northwest to a chilly 10 below in the south. I think the Twin Cities will experience low temperatures in the vicinity of 13 below all three days.

Even high temperatures are likely to remain sub-zero just about statewide for both Saturday and Sunday.

Moderation?

Forecast models are predicting some moderation of temperatures beginning Monday, New Year's Day, in the afternoon. The gradual warmup will be slowed by Canadian reinforcements mid-week, but I think we could see near-normal temperatures across the state by next Friday or Saturday, January 5 or 6.

The rest of winter

If you really want to look ahead, here is the three-month outlook for temperature departures from normal for January through March. Our part of the country is likely to trend a little colder than normal while the Southwest looks toasty.