Undercast!

If Connecticut had 3 or 4-thousand foot mountains we would have been treated to beautiful scenes like these from Killington, VT and Stowe, VT this past week.

Courtesy: Killington

Courtesy: Stowe Mountain Resort

When moisture is trapped in the low levels of the atmosphere you can get these dramatic views of an undercast. Just like overcast except under!

Frequently these areas of low level moisture get trapped horizontally on one side of a mountain and vertically by a temperature inversion. Inversions are locations in the atmosphere where temperatures increase with height (they typically decrease with height). The phenomenon isn’t rare – it happens almost every day – but when there’s enough moisture below the inversion you get clouds that are trapped.

Here’s a model forecast sounding from Springfield, VT this morning (not far from where the first picture was taken).

While temperatures near the ground are around 2ºC temperatures at 2200 ft are near 6.5ºC! That’s a difference of nearly 10ºF. Coupled that with adequate low level moisture (notice the red and green line, or temperature and dew point are close together) you get clouds.

Enjoy the undercast up north – hopefully the overcast in Connecticut breaks soon!

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Epic Upslope

Courtesy: Stowe

I got an email this morning saying:

“I have a condo up north in the mountains and I was very concerned after reading your tweets about up to 2 feet of snow this weekend… you need to be careful about your alarmist tweets”

It turns out that some areas in Vermont will wind up with 3 1/2 feet of snow from an absolutely exception upslope snow event along the spine of the Green Mountains from Killington on north!! Killington has picked up a foot, Stowe and Jay over 30″ as of 7 p.m. Saturday and it’s still dumping.

Snow like this is localized to along the spine of the mountains that run the length of the state. In this case the snow was focused in central and northern Vermont with relatively little in the south.

With westerly and northwesterly wind and plenty of low level moisture the rapid rise in elevation from the Champlain Valley to the Greens forces the air to rise rapidly. The lift  is comparable to a storm that just parks over the same spot and doesn’t move (you can’t move mountains like you can move a storm). Instead of lift being cause by processes in the atmosphere in “upslope” we get lift cause by the wind blowing up over terrain which yields upward vertical motion and if strong enough clouds and precipitation.

Here’s the radar from Burlington that shows the impressive dump of snow that continues in the mountains.

Courtesy: WeatherTap (click on image to animate)

It looks like many areas in central Vermont will see 1-2 feet total from this storm. The mountains in northern Vermont north of I-89 should see around 40″ of powder. Absolutely epic!

A Different Way to Look at Winter 2011-2012

Besides the October snowstorm this winter has been pretty much nonexistent in Connecticut. Since 10/30 there has been no measurable snow at either Windsor Locks or Bridgeport – which is remarkable for January 15!

Up north the winter has been just brutal for many ski areas in northern New England. Last week’s synoptic and upslope snowstorm was an absolute blessing for struggling ski areas. Here’s a cool way to display snow depth at the famed Mount Mansfield snow stake (just off the Toll Road in the Stowe ski area).

The green is the average snow depth by date and I also plotted this year, last year, and the also ugly 2006-2007 winter. After a very slow start up north this winter has exceeded ’06-’07’s paltry snow depth but remains below average. While last year was an epic snow year in Connecticut it took until March for northern Vermont to really exceed average with a maximum depth around 100″!

Bottom line is hope is not lost for skiers. 2 snow chances and relatively cold this week should boost Vermont bases. Though the Day 8-20 period looks very mild it’s difficult for snow depths in the mountains to take big hits this time of year. Closer to home I don’t see much for winter lovers to get excited about through early February.

A Disappointing Foliage Season

Late Color and Dull Color From the Summit of Mt. Mansfield

Up in northern Vermont this weekend the fall colors were a bit sub par. The fiery reds in sugar maples were notably more dull than usual. Other trees that were absolutely soaked in August and September by record rains had more brown leaves than green leaves or yellow and orange leaves.

A fungus known as anthracnose is impacting sugar maples. Some other trees are being impacted by the exceptionally wet 2-month stretch in late summer. As we head toward peak foliage season the weather this weekend and next week will likely hurt an already mediocre season.

Periods of heavy rain and wind over the next week will two 2 things to the foliage. 1) Weakened leaves will begin to fall from the wind. 2) heavy rain when color is out will dull the pigment that provides the beautiful yellows, oranges, and reds.

Even with dull color there’s no place more beautiful to be this time of year than New England. Let’s get some snow on Stowe’s “Front Four” I’m ready for ski season!

Some of the "Front Four" at Stowe. They Look A lot Steeper Without Snow!