Saturday Morning Vermont Update: Pretty Much Anything Might Fall From The Sky Tonight

National Weather Service map of expected snow totals.
This includes tonight snow, and lingering snow
Sunday through Monday. Click on the map to
make it bigger and easier to see. Also, 
it's a difficult forecast so don't be 
surprised if it turns out to be a little off. 

Our messy storm is on our doorstep, due tonight in Vermont and surrounding areas. 

And we still don't have a great idea of what will fall from the sky and any particular time during the storm. . But the experts are trying their best to tell you who gets snow, who gets ice, who gets rain.

In the grand scheme of things, it doesn't really matter. 

Pretty much the entire state of Vermont, and surrounding states, and southern Quebec will get a mix of snow, sleet, freezing rain and rain.  The question who gets the most snow, the most ice, the most rain? 

I'll have some sadly vague answers in a bit.

First of all, how about that wind yesterday? The Champlain Valley and northern New York really got blasted, especially in the afternoon and evening. Power outages in Vermont peaked at around 2,800 homes and businesses last night. 

In northwestern New York, winds gusted to as high as 65 mph in Malone. Here in Vermont, peak gusts included  60 mph in Jay. 57 mph in Alburgh, 53 mph on Route 2 at the Sandbar in Milton and 51 mph in Burlington. 

In contrast, it's almost a dead calm out there this morning in anticipation of our storm.

THE STORM.

Meteorologists like to look at the thermal profile of the atmosphere in this type of weather situation. That means they look at what they think the temperature will be in every layer of the atmosphere. 

In this case, I would understand if those meteorologists just threw up their hands and said, "I dunno!"

But they're professionals, so they're giving it a shot. 

National Weather Service forecast of expected ice
accumulation from tonight's storm. Most of the freezing
rain will be in the mountains central and south.

A high pressure system that will be off to our north and east will try to feed cold air into northern New England as the double-barreled storm comes at us from the southwest.  We're also looking at that new storm developing along the New England coast. How fast and strongly develops will also help determine whether the cold air wins out, or the warm air takes over. 

The dense, cooler air trying to come in from the northeast will tend to hug the ground. Warm air will glide up over that chilly air.  

Where the cold air is the atmosphere and how thick layers of warm air will be overhead will determine which kind of stuff falls from the sky. That's our thermal profile. 

The bottom line is different types of schmutz will fall from the sky at different times. All we can do is try to predict what the predominate precipitation type will be.

Early guesses are this will be mostly snow toward northeastern Vermont. You'll see more sleet as you head south and east across the state. 

Here's another complication. As falling snow enters the warm layer in the atmosphere, it melts into raindrops. If the cold layer is thin, that rain stays unfrozen until it hits the ground, and turns to ice. That's freezing rain. 

If the cold layer near the ground is thicker, the raindrops freeze on the way down. They become little ice balls - sleet. 

As the National Weather Service describes it, some higher elevations might see some freezing rain, as the rain won't have time to turn to ice on the way down. The best chance of freezing rain with this storm looks like it'll be in the southern Green Mountains of Vermont and southern Adirondacks of New York. 

A winter weather advisory is in effect in those two areas because of that freeing rain risk.  I don't think the freezing rain will be enough to bring down much in the way of trees and power lines. It will be mostly a dangerous road type of situation. 

This mess should start around 6 to 8 p.m. this evening in southern Vermont and 8 to 10 p.m. central and north.  At least it's hitting at night on a weekend, so the effects on travel aren't so bad. 

The best guess on snow amounts by tomorrow are two to five inches of snow in the Northeast Kingdom, one to three inches central Vermont and the Champlain Valley and less than an inch south. This will be a heavy, wet snow, especially since many areas will have some sleet, freezing rain and rain mixed in with it. 

Expect surprises, with some areas getting more or less snow or ice than predicted. This is an easy forecast to screw up.

During the day on Sunday, more snow showers will continue, mostly north and northeast. For awhile Sunday, some of the valleys could see raindrops mixed in as cooler air will take its time coming in. 

Another one to four inches of snow looks like it fall Sunday and Sunday night in most of the north. They would be somewhat more than that in the northern Green Mountains. And there would probably be a little less than that in southern Vermont and in the central and southern Champlain Valley. 

The Adirondacks in New York and the White Mountains in New Hampshire looks like they will get some additional snow Sunday night as well. 

The forecast for the upcoming week is starting to look more complicated than earlier thought, too. But I'll get into that in a later post.