Pacific Invasion: A shot at 50 Saturday

You'll get another chance to hang those holiday lights this weekend.

Dreams of a White Christmas may be fleeting for many Minnesotans this year. A massive December thaw is less that 48 hours away. If the forecast models are right, there's a 50-50 shot at a few hyperactive bank thermometers near you blinking 50-degree mark sometime Saturday afternoon.

Old Man Winter is about to go on an extended December holiday.

The mechanism for our now imminent December thaw? A massive change in the upper air pattern that is sending a series of storms barreling into the West Coast, and a gush of unseasonably mild near record Pacific air eastward into the Plains.

Watch as wind turn south and blow from snow free lands behind departing high pressure over the Midwest by Thursday.

Temperatures may brush past the thawing point as soon as Wednesday, but the invading Pacific air mass kicks into high gear Thursday afternoon. By this weekend, freezing may be a memory, and any snow on the landscape isn't long for much of Minnesota.

The European Center for Medium-Range Weather Forecasts model is the most aggressive with the weekend warm up, pushing the thaw into Monday.

White Christmas on life support?

Historically the chances of a white Christmas in the Twin Cities run at about 75 percent. About three of every four  years feature at least one inch of snow cover. This year, I'd chance of a white Christmas in the Twin Cities at 50-50 -- and dropping fast.

A white Christmas up north in Hibbing and Ely has historically been close to 90 to 100 percent probable.

Here's more on the historical chances for a white Christmas form the Minnesota Climate Working Group.

Will we have a white Christmas? It's an age-old question that occurs to almost everyone this time of year. The chances of having a white Christmas vary even here in Minnesota. Having a white Christmas is loosely defined as having 1 inch of snow on the ground on Christmas Day. The snow depth at most sites is measured once a day, usually in the morning. The best chances of having a white Christmas is almost guaranteed in the Boundary Waters Canoe Area and a good part of the Arrowhead. The chances decrease to the south and west and the best chance for a "brown" Christmas is in far southwest Minnesota where chances are a little better than 60%. Northern Minnesota is one of the few non-alpine climates in the US where a white Christmas is almost a sure bet (U.S. White Christmas Probabilities).

In 115 years of snow depth measurements in Twin Cities, a white Christmas happens about 72% of the time. From 1899 to 2013 there have been 32 years with either a "zero" or a "trace." The last time the Twin Cities has seen a brown Christmas was 2011.

Last year about 3 inches of fresh snow fell Christmas Day, and a 6" snow depth decorated the landscape. Santa rode the Polar Vortex to navigate a temperature of -13 Christmas morning.

This year, Santa may need the sleigh with the Rollerblades.