Vermont Winter Storm Watches Now Up For Messy, Iffy Nor'easter

The National Weather Service in South Burlington has taken
a first crack at forecasting snow amounts from the upcoming
storm. Click on the map to make it bigger and easier to see.
Also, expect some noticeable adjustments to this 
forecast map between now and Friday. 

 The National Weather Service in South Burlington has gone ahead and hoisted a winter storm watch for all of Vermont except the Northeast Kingdom for the long anticipated storm that is forecast to begin late Thursday night and continue into the weekend.  

We still have a lot of question marks about this storm, including where the heaviest snow falls, how much rain mixes in and where, and the exact track of this system.

It is becoming more clear, though, that this will be a messy one.  Snow that does fall will be wet and heavy, which frankly isn't my favorite. It won't be a classic winter powder fest, that's for sure, although the snow won't be as soggy way  up high in the mountains. 

Prepare for some power outages, tree damage here and there, and a crappy Friday morning commute.  Chances are Friday evening won't be that great, either.  Wet snow on roads tends to be even more slick than more powdery stuff. This will be also be a back-breaker to shovel. 

Remember, a winter storm watch means maybe, get ready just in case. A winter storm warning would mean it's inevitable. The National Weather Service might end up changing the winter storm watch to a winter weather advisory if some places look like they won't end up with all that much snow. We'll find out, won't we?

You can see the uncertainty in the forecast given the predicted snow totals from this morning. Anywhere from four to 16 inches might fall, with locally less amounts in some deeper valleys and more in some favored upper elevations. 

There's a big bust potential, too. Here's a for instance: The NWS in South Burlington puts out those maps you're familiar with that give predicted snow totals. That map gives Burlington a paltry storm total of 3.8 inches, but much more in higher elevations. 

Dig deeper into the NWS website and you see what are called probabilistic forecasts, which give what could be the highest end snowfall out of a storm like, and the lowest end. The range between these two maps is especially wide as of this morning. 

If the storm over-performs, it gives Burlington 10 inches of snow. If the storm under-performs, just two inches.

Overall, east facing slopes that are not on valley floors will probably receive the most snow. Especially in southern Vermont. I'm looking at you, towns like Ludlow, Mount Holly and Shrewsbury. The Northeast Kingdom might not see all that much, as the White Mountains in New Hampshire could block most of the moisture from reaching that part of the state.

The Champlain Valley might also see some moisture blocked by the Green Mountains, and of course the possible mix or change to rain on Friday. It's possible the back end of the storm Saturday could partly make up for that risk of a Champlain Valley snow bust on Friday. I think the further you are from Lake Champlain, the more snow you'll get. 

It does look like any precipitation we get will come in waves, with lulls in between lasting a few hours where little or nothing comes out of the sky. The first thump would come through Friday morning, with another one possible Friday afternoon, with more, somewhat lighter periods of snow or mix

Here are some reasons why this forecast is a real headache for meteorologists.

Most computer forecasting models bring the storm as a nor'easter right up along the New England coast. The American model insists on it curving out to sea for some reason, which would give us much lighter amounts. For now, the betting is that the American model is mostly wrong. But it could surprise us!

Note that even a slight shift in the forecast track will have a huge effect on the amount of snow and/or rain comes down. 

Temperatures are really tricky. It'll be right around the freezing mark for most of the storm. If the Champlain Valley, lowlands in Rutland and Bennington counties and the Lower Connecticut River valley get warm enough, we could see a fair amount of rain and less snow.  It's a tossup, really. 

How much will the Green and White mountains block moisture in valleys just to the west of those mountains?  That one is kinda tricky. 

Definitely expect some adjustments to the forecast between now and Friday. Don't take what I just outlined in this post as gospel.

It still looks like most of any snow that falls out of this storm will stick around through Christmas given an expected relatively chilly weather pattern between now and then.