Think Snow, Tweet Snow !!!

Wednesday, February 14, 2007

Storm Update: The Valentines Day Blizzard of '07 !!!

The storm has commenced and is proceeding as expected as of this morning. Latest indications are that the low pressure center will track almost directly over Providence and Boston then proceed out over the water before again tracking inland again over Downeast Maine. Incredibly, the american model strengthens the storm to 974 mb as it spins into the Canadian Maritimes which in turn means a very tight pressure and temperature gradient across much of New England and thus the blizzard warnings. Temperatures across Vermont are still near zero in many areas as of this morning and will struggle to rise above 10 at MRG through the duration of the storm. In contrast, do not be surprised to see temperatures climb to 60, yes 60 degrees on Nantucket, Marthas Vineyard and parts of the eastern Cape this evening. Its hard to believe that can happen but such makes the incrediants for a big storm in Vermont.

The Sleet Concern
The big concern as far as the forecast goes is the sleet. The mid-layers of the troposphere have been warmer than expected in many areas while surface temperatures have actually been colder than expected. As a result sleet has fallen in many areas which were not expected to see much. Model cross sections tell the story and will certainly do so in this storm. The cross section for Concord, NH shows that a critical layer will rise above freezing later today (2 C) and this evening and precpitation is likely to go to sleet thus holding down total snowfall accumulations.

http://coolwx.com/cgi-bin/getbufr.php?region=NH&stn=KCON&model=nam&time=current&field=tempa

The cross section for Barre-Montpelier is considerably colder and does not show temperatures above freezing at any layer while precipitation falling on Wednesday and Wednesday night. That being said, temperatures are shown to climb to about -2 C (28 degrees) at about the 7,000 foot level this evening (temps at the surface will be much colder).

http://coolwx.com/cgi-bin/getbufr.php?region=VT&stn=KMPV&model=nam&time=current&field=tempa

Considering that temperatures at these levels have been warmer verses the model integrations, it would not be surprising to see a few sleet pellets mix into the precipitation briefly this evening although I do not think it has a significant impact on accumulations. It will be interesting to watch the temperature at Mount Washington, a location which is positioned at the lower part of the temperature inversion. By Wednesday evening, temperatures at the observatory should be 15-20 degrees higher then what MRG's Stark Mountain will be reporting.

2-feet and probably more
In spite of all the above technicalities, the forecast is on track and with the snowfall already being reported at MRG, total accumulations are likely to exceed 2 feet on the mountain. The wind will be a significant isssue if your traveling or skiing later today, tonight and into tomorrow. Winds, although they are calm as of Wednesday morning, will gust to gale force later today on the summits and gust to hurricane force this evening and tonight. No hurricane wind gusts are expected during the day tomorrow but it will remain extremely windy so check madriverglen.com for details on any wind holds.

2 comments:

hock said...

Hi Josh, Thanks for the update. Your update is better than any of the weather channels since it is local to the area and seems spot on.
TJ

Patrick said...

Thanks for the update, Josh. But it might be time for another, since I just measured about 35" at the base of Mt. Ellen at Sugarbush, and it's still a dumpin' away!