Strange, Extreme Temperature Inversion To Finally Break, Then Freezing Rain, Then Rain To Mar Runup To New Year

Freezing fog under an inversion broke up Thursday 
morning, leaving frosted trees glistening above an
old farmstead near Wallingford, Vermont. 

 Though it might not seem it to the casual observer, the weather has been really strange from Christmas Day to this morning in and near Vermont. 

As previously forecast, an extreme temperature inversion has taken hold.  To remind you, an inversion is when it's warmer aloft or up in the mountains than in the valleys. Usually the opposite is true. 

Inversions are more common in the winter around here, but this one is really something. 

Atop the high peaks of the Adirondacks Thursday morning, like the summit of Mount Marcy, temperatures remained in the mid 30s, even at night as temperatures in the coldest valleys got down to below zero readings. That's about as extreme a temperature inversion as I've ever seen.

The inversion has trapped the steam coming off unfrozen Lake Champlain, creating a widespread blank of low clouds and fog to spread out from the lake and cover most of western Vermont and nearby New York, both yesterday morning and this morning. 

With light north winds, I noticed the clouds were never able to break up Thursday downwind of Lake Champlain. Much of Addison County, southern Chittenden and northern Rutland counties remained socked in with clouds, even as most other areas cleared.

Where the low clouds and fog did break up in those chilly valleys, the freezing fog left behind a beautiful frost on all the trees, lit up by the low angle late December sun. It was an example of how inversions can be stunningly beautiful.

Freezing fog early Thursday left these trees in 
West Rutland, Vermont beautifully frosted over. 

This morning, temperatures in the inversion remain topsy turvy to the extreme. Under clear skies early this morning, it was 9 below at Lake Eden, Vermont and minus 7 in Morrisville. The low clouds and fog from Lake Champlain kept Burlington a little warmer at 14. 

Meanwhile, it was still in the low 30s in the high peaks of the Adirondacks. The summit of Mount Washington, New Hampshire, a place you usually find extreme cold, it was a balmy 28 degrees a little before dawn.  

Freezing fog has been an issue in spots and night, but it's been beautifying our surroundings during the day, especially where sun breaks out. The sun glistening on trees frosted over by the fog is just stunningly beautiful, so enjoy that if you see it. 

FREEZING RAIN

The inversion will gradually fade as the strong high pressure system finally exits in favor of that storminess we've been watching approach. 

Still, the inversion's fading glory will cause new problems.  That warm air aloft will continue flowing in, and will try to work its way down into the valleys. But only grudgingly.  An initial wave of precipitation is forecast to push northward into New England  Saturday while fading as it encounters dry air over Vermont and New Hampshire. 

What does arrive will start out as plain rain as it falls through the mild air a few thousand feet overhead. But it will probably freeze on impact as it lands in the cold air and cold ground down southern Vermont valleys. 

A winter weather advisory is up for the southernmost two counties of Vermont and adjacent areas of New York Saturday as that freezing rain arrives.  It won't come down hard, so there will be no issues  with trees and power lines, but there will be icy problems on the highways. 

There's some question as to  how far north Saturday's freezing rain will get, but a little dab will do ya - Even 0.01 inches of freezing rain is more than enough to make roads and sidewalks dangerous. I have a feeling those Saturday winter weather advisories might get extended at least into central Vermont.  

Not sure yet, but it's something to watch.

A more substantial surge of warmth and moisture will push northward Sunday, so we get more rain. Some valleys in eastern Vermont might not be above freezing yet even on Sunday, which opens the door for more freezing rain. 

In western Vermont, temperatures are forecast to be above freezing when the rain arrives, but that might not be much help. 

The air temperature might be in the mid and upper 30s while it's raining Sunday, but the ground will not have recovered from the cold valley temperatures we've had under this week's inversion.

 Pavement, concrete, etc. will still be below freezing, so that rain Sunday would probably freeze on roads, sidewalks and driveways. Especially if they haven't really been hit with the state and municipal salt shakers that I expect will be out. 

Eventually, it will warm up everywhere in Vermont by Monday for just plain rain.