Wednesday Evening Vermont Storm Update: Some Winter Watches Upgraded To Warnings; Long Storm Likely

A new snow forecast map issued by the National Weather
Service office in South Burlington. Click on the map to make
it bigger and easier to see. Compared to this morning's map.
expected snow totals have increased somewhat. 

 As they always do, the National Weather Service in South Burlington has been refining their forecast for what will probably be the first major winter storm of the season in Vermont late Thursday into Saturday.  

Also, as expected, there have been some changes to the forecast. Most of those changes favor snow lovers. But that doesn't mean everybody gets a huge dump of snow.  We still have question marks and red flags with this storm forecast.

You know, all those meteorologists trying to forecast this storm seem so cool and collected. But I bet they're pulling their hair out trying to get this one right. And drinking, perhaps heavily, after their work shifts. This is a tough forecast. 

The winter storm watch has been upgraded to a winter storm warning for central Vermont from Lamoille County all the way down to the Massachusetts border. In those areas, confidence has increased enough that a pretty decent dump of snow seems inevitable from late Thursday night into Saturday.

Those of you in the winter storm warning zone can expect 9 to 18 inches of snow, but some favored spots could end up with two feet of new snow by Saturday afternoon. That's at least according to the latest thoughts from the NWS Burlington.

If things pan out as currently expected this will really be a great high elevation snow, perfect for Vermont's ski industry as we gear up for the Christmas holiday. The resorts have been making snow, and they've gotten a little natural stuff in recent days, but they can really use the boost from a big dump, and the publicity surrounding said big dump.

I'm sure the marketing departments at Vermont's resorts are working overtime on this to get the word out, if this dump actually happens. 

Elsewhere in Vermont, we're still under a winter storm watch, not a warning. The Northeast Kingdom was not under any kind of alert this morning, but that winter storm watch has now been expanded to include them as well.

It makes sense that the National Weather Service hasn't upgraded that watch, as there's still some questions.  Uh, some questions? Many questions. Like exactly where the storm goes, how much moisture it has to play with, how warm it will get and the precise wind directions. That'll all greatly influence how much snow any particular place gets.

(Remember, a winter storm watch means conditions are favorable for a winter storm. A winter storm warning means a big, noticeable storm is pretty much inevitable).

In general, though, the predicted amount of snow in the forecast area wide is a little more than what was in the forecast this morning. 

What follows is what the National Weather Service in South Burlington thinks will happen with this storm. As you know, new data could make them change their minds and come up with a different scenario for this storm. But here's what the thinking is for now:

The initial thump of snow still looks like it wants to come through from a little after midnight Friday through the Friday morning commute.  The morning commute looks like it could be a huge mess virtually statewide, with wet snow coming down at a rate of one to two inches per hour.

You might want to start working with your boss to just work at home instead of driving to the office, if possible. I'd expect a fair amount of school closings, too. So plan on entertaining the kiddos at home. I'd just make them shovel the driveway.

During the afternoon, it looks like the moisture feed coming off the Atlantic would come almost directly from the east, or maybe southeast. That might keep the snow going full blast on the eastern slopes of the Greens, and the summits. That's a big part of the logic behind the new winter storm warning in central Vermont.

In this scenario, the Green Mountains would block a lot of the moisture from getting into the Champlain Valley, and the low elevations in southwestern Vermont all the way down to Bennington. In these places, the snow would taper off to just light stuff or nothing at all. it will probably warm up enough to also create periods of light rain and/or drizzle in these valleys. Sounds lovely. 

For snow lovers in the Champlain Valley, there is some hope. Friday night and Saturday, the wind will shift to the north, and moisture will still be feeding in from the Atlantic from this slow-moving nor'easter. 

When you get a set up like that, the air coming in from Quebec gets squeezed between the Adirondacks and Green Mountains. When the air gets squeezed like that, it has to rise to have room. Rising air encourages moisture to cool, condense and fall as snow. If things work out just right, that would mean several inches of snow for the Champlain Valley Friday night and Saturday. 

This is still expected to be a wet, heavy snow, especially at elevations below 2,000 feet or so. That's most of us, frankly. If the snow comes down as hard as some forecasts indicate, expect at least scattered power outages. 

Get your LED candles ready Thursday night just in case and charge your devices.

There's still a ton of wild cards as of this Wednesday evening that might make this forecast a bust, or at least create some major changes.

As I mentioned this morning, the American computer models insist on taking the main nor'easter well off the coast, which would diminish how much snow we'd get. As of late this afternoon, the American model was still insisting this would be a case. That's at odds with all the other models, which say the storm will go along the coast.

Just because the Mean Girl other models are ganging up on the American model, we can't say the computer model from the good old U.S. of A is wrong. Maybe it's seeing what nobody else is seeing?

We don't know how warm it will get. On paper, it looks like the valleys will get above freezing for just a few hours, if at all, and the warmest temperatures would come when the precipitation is lightest.

I've often seen the computer models underestimate the strength of warm air intrusions with storms like this. Especially early in the winter. Also, the water temperature off the New England coast is warmer than normal. Will that make the air coming into northwestern New England warmer than predicted, and give us more rain?   Maybe.

If you're a snow lover and get burned by this storm, you still have a shot at joy. Longer range forecasts - though not always accurate - are suggesting below normal temperatures and above normal precipitation well into the week between Christmas and New Year. That would suggest plenty of snow.

I wouldn't hang my hat on that scenario, but maybe! 

As is always the case in a situation like this, expect an update from me tomorrow morning.