A major snowstorm will affect 100 million people across the Midwest and Northeast

What appears to be the most shocking snowstorm of the winter so far has its eyes set on pouring snow from the midwest to the northeast, affecting more than 100 million people. Some cities may be buried up to 18 inches of snow early next week.

Cities from Chicago to Cleveland to Washington, DC to New York are watching and waiting to see what the storm will do as it slips east this Sunday to Tuesday. This is the same storm system as wet parts of California with up to 15 inches of amazing rain and over 100 inches of snow this past week.

Right now, the storm is in the southwest and is moving east. At the same time, the brutal cold has engulfed the Great Lakes and the Northeast, where wind chills are as low as 20 degrees below zero in some areas of New England.

This cold air carries both the promise of a major snowstorm and the complication of perhaps too cold. This is because this cold air is associated with an atmospheric block. The strength of this block will determine whether Washington, DC is buried in heavy snow or whether the target reaches New York City and southern New England.

In other words, will this block suppress the storm track south or allow the storm to climb north? Right now, it’s too early to tell. So far this winter, snowfall in Washington, DC, has been almost non-existent, with only a third of an inch.

What we do know is that a lot of snow will fall in the Midwest Valley and the Ohio Valley on Saturday night and Sunday from Chicago to Cleveland and the surrounding area. In all, the heaviest snow band should pour 6-12 inches on Sunday night, including perhaps Chicago, Indianapolis and Columbus.

On Sunday the storm will move toward the east coast, spreading snow across parts of Virginia and southern Pennsylvania. In an effort to undermine the cold air block, the storm will transfer its energy to a developing coastal storm along the North Carolina coast. Snow can be heavy at times in places like Washington, DC

Now comes the tricky part. Is the storm slipping into the sea to the east, keeping the cold air closed in the Washington area and the heavy snow bullseye between DC and Atlantic City? Or does the storm move northeast, burying New York City, Providence and perhaps Boston with more than a foot of snow?

It’s too early to be sure. But it looks like the blockade scenario will cause this event to be prolonged and some cities to see snow for 36 hours, from Sunday to Tuesday. Anyone who sticks under the heavy band will probably grab 12-18 inches, with isolated spots about 20 inches.

If the snow reaches New York City, it would probably start Monday morning and then arrive in Providence on Monday afternoon. The storm should come out Tuesday night.

Below is a comparison of two models showing two different potential outcomes. The first is the American GFS model from Friday morning showing heavy snowfall from Washington, DC to New York City. Below is the Thursday night European race, which shows the heaviest snow gliding south of New York City and trimming eastern New England.

Details will become clearer once a given city is within 48 hours of the storm’s arrival. So stay tuned …