Saturday, December 8, 2007

Preliminary forecast for Sun-Mon

Some notable changes here in Keene based on the 12z model runs and 18z NAM. Basically added more of a gradient around the Mass Pike, keeping totals almost the same to the south, but a little higher further north. Looking like the frontal boundary will not jump as far north as previously thought. This now gives a mostly snow event here. Generally all snow through 10pm Sunday, changing to sleet through the rest of the storm, possibly mixing with freezing rain Monday morning. QPF is still an issue with the models, moreso to the south, consensus here though remains .25 to .5.

Snowfall forecast for 12z Sunday through 00z Tuesday: 2" - 4"
Ice accumulation forecast for 12z Sunday through 00z Tuesday: .1"



P.S. 1700EDT
NWS forecast coming out now with amounts of 4 to 8 inches. While 850mb temps have trended colder, I believe that the NWS is very high considering two points:
1) QPF on all models does not support 4 to 8 inches of snow, even if we were talking all snow. There is a consensus for .25 to .5 which under normal dendric snow growth conditions, would support 3 to 6 inches.
2) Dendric snow growth conditions will be below normal, allowing for more sleet than snow especially after 10pm Sunday.

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