April Snow Possible for Northeast Friday

By Alex Sosnowski, Expert Senior Meteorologist

April 2,2013; 5:49PM,EDT

A storm set on bringing chilly, drenching rain to the South is being watched for possible impact on the Northeast in the form of cold rain and inland snow for some areas Friday.
While the weather pattern has changed to allow brief episodes of warmth, it has not completely shifted to avoid possible wet snow events in the region just yet.
With the advance of the spring season, the risk of accumulating wet snow along the mid-Atlantic and southeastern New England coast drops off exponentially this month.

This photo of snow on daffodils was taken on April 7, 2007, in the Washington, D.C. area by Flickr user FredoAlvarez. If wet snow were to fall from the storm later in the week, it would occur much farther north than the southern mid-Atlantic region.

However, a storm has appeared on the horizon which, if it turns northward along the coast, could throw wet snow over interior areas from the northern mid-Atlantic through New England, especially over the higher elevations of the same areas.
After a warm start to the week, colder air spread from the Great Lakes to the coast in the Northeast Tuesday and will stick around through the week.
Whether or not the storm makes the troublesome northward turn depends on if the two branches of the jet stream phase.
The jet stream is a river of high velocity air located several miles above the ground. This river of air can contain several channels and can have eddies therein.

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Northeast's Potential Storm Impacts the South into Friday

If the southern channel containing a rainstorm syncs with the northern channel containing a disturbance and colder air, then a large storm tracking close to the coast could result.

Such a storm would likely bring drenching rain on the coast and rain or wet snow inland, depending on elevation.
If the two channels of the jet stream remain separate, then the southern storm will simply head out to sea with only a batch of rain brushing southern and coastal areas of the mid-Atlantic, while cold, dry air hangs on or is reinforced over New England and the northern mid-Atlantic.

There is a greater chance of the two channels getting together to bring snow to part of Atlantic Canada this weekend.
Beyond the close call with the storm Friday, it appears progressive warmth will win out in much of the East during week two of April. However, much of the West may plunge into chill and stormy conditions into the middle of April as the jet stream drives southward west of the Mississippi River and plays a balancing act.
There is also the potential for sneaky cold air to sag southward from eastern Canada into New England and part of the mid-Atlantic. Areas south of this boundary are likely to have multiple days with highs in the 70s. North of the back door cold front, temperatures may hover in the 30s at high noon with clouds and misty rain.
This shift is not a sign that the East is completely done with chilly weather. Additional fluctuations in the jet stream are likely moving forward into the spring.