Sunday, February 10, 2008

Squall line moving through NY

Recap:
A good light to moderate snow event yesteday gave Keene 4.0" of wet, but fluffy snow. This morning, already great dynamics in place with available moisture allowed for an area of precipitation associated with a prefrontal trough to move across southern and central New England. This dropped another .6" of snow on Keene.

The main story with this last area of snow in Keene was a brief line of heavier snow that moved through around 12:15pm. This reduced visibilities to .2 to .4 miles across Cheshire County, while dropping a quick .1" of snow.

Below is the Keene airport METAR ob at 12:15pm. The first bolded text is wind gust to 35kts, or 40mph. The second bolded text is visibility of .25 miles.

METAR KEEN 101715Z AUTO 23005G35KT 1/4SM BKN003 OVC011 00/M03 A2945 RMK AO1

In addition to the show in Keene, in Walpole, a spotter reported in thundersnow.

The rest of today:
That was the first report of thundersnow today in SNE, but wont be the last. An intense squall line is setting up across New York, currently with max radar returns near 40dBZ. Clouds will thin over the area over the next half an hour, allowing some warming. Additional solar heating has the same effect on a thunderstorm day in the winter as in the summer. Already, mid level lapse rates exceed 7C/km across the northeast, with 9C/km down into NJ and CT. Low level lapse rates are also increasing across the region, and will amplify more as the day goes on. One concern is the fact that this morning's snowfall may have robbed some moisture from the system, but considering the reports coming out of NY, that probably wont minimize effects too much. Currently a handful of reports of thundersnow in from ELM,ROC, and SYR. As for timing, count on 4:20pm to 5:00pm.

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Another snow and ice storm on its way for Tuesday and Wednesday. Looking like at least some moderate accumulations. Latest forecast coming up tonight.

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