Sunday Morning Vermont Storm Forecast: Snow/Power Outage Worries Grow; Flood Threat Diminishes

The ever-present, ever-handy latest National Weather 
Service snowfall prediction map. This is the latest
update issued this morning, and expected totals
have ticked upwards from previous forecast maps.

 The outlook for our big storm, set to begin hitting Vermont later today, keeps getting colder and colder, meaning this will be a bigger, badder snowstorm than anybody would have imagined a few days ago.

A winter storm warning is now up for all of Vermont except the lower Connecticut River Valley floor from about White River Junction south. In that area, a lower-dose winter weather advisory has been hoisted instead. 

Even though this will be a somewhat colder scenario than previous forecast, the snow, when it arrives, will be wet and heavy.  

Ground zero for power outages in the last two storms were mid and higher elevations away from Lake Champlain in central and northern Vermont.  This time, lots of power outages are likely pretty much everywhere, but the Champlain Valley might end up being the hardest hit. 

The Champlain Valley will be a little warmer than the hill towns, so the snow there will be especially wet and heavy. Worse - and this goes for nearly the entire state - snowfall rates will be at times one to two inches per hour from the predawn hours through at least noon. 

When wet snow piles up that fast, it tends to plaster itself to trees and power lines much more efficiently that if weren't coming down so hard. 

 Additionally, gusty north to northwest winds will load the snow on the north side of trees and less on the south side. That makes the trees unbalanced, making them more likely to topple onto power lines. 

This is a really dynamic storm. The first signs of that fact became apparent yesterday and last night. The storm produced a deadly tornado outbreak in and around Tennessee. I'll get into those tornadoes in a separate post today. 

Being such a powerful storm heading north along the New England coast, it will produce LOTS of precipitation.  Rain and melted snow will amount to 1.5 to 2.5 inches, with locally higher amounts. That's a big total for a December storm. 

Storm clouds gather over St. Albans, Vermont Sunday
morning ahead of what is expected to be a very disruptive
snowstorm. Rain will change to heavy, wet snow overnight.

On the bright side, this snowier scenario has diminished the flood risk.  The chances of flooding are now mostly limited to areas from Route 4 south, and any flooding should be pretty minor. Central and eastern New England are now under the biggest threats from flooding

It's really amazing how much the storm and its predicted effects changed in the last week. It was first thought it would be almost exclusively a rain storm and flood. Now, the heavy snow has taken center stage. 

Days ago, the storm was expected to pass to well to our west, maybe near Toronto. Now, it's expected to head north along the New England coast, probably passing right over Boston. 

HOW IT PLAYS OUT

It's warm out there this morning, and scattered showers are starting to roam around Vermont. It's in the 40s to near 50.  Many of us will get into the 50s later this morning before the steadier, heavier rain arrives by early afternoon. 

Temperatures will sink back through the 40s this afternoon, but there's no risk of a changeover to snow before evening. If you want to get out and pick up groceries and supplies and such before the storm, the only hazards you'll have to deal with is hydroplaning on highways in the rain. There might be some standing water and such here and there, too.

Temperatures will continue to slowly sink this evening. Rain will change to snow first on the mountain tops, then reach valley floors starting around midnight to 2 a.m. in western Vermont. That's when the trouble really begins. 

The heavy, wet snow will continue to spread, probably hitting all of Vermont except the lower Connecticut River Valley before daybreak.  

For those who have to drive to work Monday morning, this is a nightmare scenario, since the heaviest snow will probably hit during drive time.  It'll snow too hard for state snow plows to keep up.  Heavy wet snow is more slippery, and harder to plow than the more powdery stuff we're used to.

Back roads will also be a mess of snow, fallen trees and branches, and maybe snapped power lines. Many of those back roads will be impassable at times. I think some sections of Interstates and other major roads in Vermont might also close due to car crashes, fallen trees and power lines.

If at all possible, don't drive anywhere Monday, especially before noon. There will be nothing to get to anyway. I'm sure many schools will close, and many events will be canceled or postponed.

The snow should gradually become lighter and eventually more scattered as we head into late day Monday and Monday night. Roads should still be a mess, and power outages will be ongoing. Winds gusting to 35 mph will ensure snow loaded trees and branches will continue to snap. 

Yeah, this storm is a real pain in the neck

SNOW TOTALS

If this storm was a "normal" winter event for Vermont with our prized powdery snow, almost everybody would be getting at least a foot of snow, with several places closing in on two feet, easily.

But since this is mostly a miserable "wet cement" type snow, totals won't be quite that high, but still pretty impressive.

All this is subject to change, of course, but pretty much everybody north and west of a line from Bennington to St. Johnsbury should see at least six inches of snow. 

The big bonus zones - areas that could easily see a foot of snow, include the northern and eastern Champlain Valley, most of the northern third of Vermont and the Green Mountains from roughly Killington north.  I wouldn't be surprised to see 18 inches or more at summits like Mount Mansfield or Jay Peak. 

The "escape zone" from this mess is the lower Connecticut Valley floor, which will see totals ranging from a slushy coating to three or four inches. 

Remember, this is "heart attack" snow, so shovel it away slowly and methodically, and take breaks. Or get some healthy teenager to help you with it. 

I'm sure the forecast for this storm will continue to be tweaked, so stay tuned for updates going forward. The National Weather Service and Vermont's excellent television and radio meteorologists will always be there, staying on top of this and providing updates.