Saturday, March 29, 2014

Another Wintry, Messy New England Storm Tonight

Time for some replacement snow!  
Heavy, wet snow weighs down trees in
St. Albans, Vermont in April, 2010.
Similar scenes are possible in
northern New England by Sunday morning.

The way this spring has worked in northern New York, Vermont and New Hampshire is as soon as a bit of snow thaws away, Mother Nature replaces what was lost with another storm.

And, after yesterday's replacement snow melted in afternoon rain, we've got another wintry storm to deal with.

This one has high bust potential, which means in some places the forecast really won't work out as forecast.

Here's what we're sure of: There is a storm loaded with lots of moisture and lots of precipitation heading into the Northeast tonight.

Flood watches are up from eastern Pennsylvania, through much of metro New York on up into southern and central New England into coastal Maine. There, it looks like a safe bet there will be mostly if not all rain, and plenty of it.

Hence, the flood watches.

Once you get into northern New England and northern New York, things get really, really tricky in the forecast department.

Warm air high up in the atmosphere will blow in, which would want to keep precipitation rain. But cold air is going to bleed down from southern Quebec near the surface. With warm air above and cold air below, that would argue for sleet and freezing rain.

But when heavy precipitation moves in, the entire atmosphere overhead cools. That would argue for snow.

So which of these three influences win out? The low level cold air? The higher level warm air? The heavy precipitation cooling everything down? All of the above?

Who knows? All this means we're not entirely sure what's going to come out of the sky tonight in northern New York, Vermont, New Hampshire and the northwestern two thirds of Maine.

The best guess, in northern New York and Vermont is wet snow, mixed with rain at the beginning of the storm this evening and as it tapers off Sunday. Sleet mixing in is a good bet.  Freezing rain is a risk, too. The best chances of heavier accumulations of ice from freezing rain is in the high elevations from 1,000 to 2,000 feet, according to the National Weather Service in South Burlington.

This snow, slush and ice is all going to be wet and heavy, so look out for fallen branches, trees and powerlines overnight in northern New York and northern New England.

The guestimate of how much snow and slush will accumulate is about three to six inches.

In the southern third of Vermont, the southern two thirds of New Hampshire and in New York from Lake George south, it seems as if most of the precipitation will be rain. It might be enough, combine with melting snow, to loosen ice in frozen rivers, so ice jams are a risk.

It's kind of hard to say exactly where the line will be in this region between wintry precipitation and mostly rain, so you sort of have to play by ear tonight.

Precipitation lightens up, but light rain and light freezing rain will continue much of Sunday night into Monday morning in many spots.

In other parts of the nation, winter rolls on, too. Blizzard and winter storm watches are up for much of the Dakotas and Minnesota Monday as yet another wintry storm system blasts through that region.

At this rate, towns will hold community snowball fights on the Fourth of July.

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