Monday, January 17, 2011

Several inches of snow Tuesday, only a brief period of rain Tuesday

Another couple rounds of model data have allowed us to fine tune the forecast and the fine tuning has a bit of good news. Snow should begin on schedule tomorrow but it appears some of the deeper moisture associated with the developing Atlantic system will move into north-central Vermont while temperatures are still supportive for snow. To make an attempt at exactitude, lets say about 10 AM for a start with snow falling at a moderate intensity by early afternoon. By early evening we should have at least 3-6 inches of snow on the ground while we try and fight off the surge of mid-level warmth that will have temperatures close to the freezing mark at about 7,000 feet.

This critical layer of warming looks thinner on the latest cycle runs and perhaps thin enough and weak enough so that we can avoid a deadly period of freezing rain. A mixture of snow and sleet, which is pretty much the best case scenario would still have the effect of locking down some of our deepened base without the problematic breakable crust. Its too close to call at this point so lets just say it can go either way.

Moving on to later in the week where the SCWB has teased about another significant snow producer. Indeed we are starting to establish a much better consensus on a storm which should track out of the southern Rockies Wednesday and proceed across the country during the day Friday. The storm appears to be a late bloomer, like many east coast storms. Precipitation will appear scattered and disorganized across the Great Lakes but intensify as the storm begins the deepen off the New Jersey coast. This particular system will get a big kick in the rear end by the incoming polar jet and will proceed very quickly out into the maritimes. Its track however, which we think right now is over Cape Cod, would have us getting several inches of the good stuff by Friday first tracks. The disclaimer here is the cold. It is finally our turn to get the full onslaught of winter's chill. We will get what some might call a "foreshock" Thursday with temperatures near 10 on the mountain but temperatures will plummet to near zero in the wake of any snow Friday and fall to between -10 and -20 each of the two weekend mornings.

A positive PNA will become the driver of a still favorable pattern beyond the 23rd of the month and likely to the end of the month. There is likely at least one more big snow producer in the mix during this time frame as temperatures try to moderate. I say "try" because we are likely to see another push of cold at some point during the last week of January but the ensembles at face value indicate that this weekend could be the coldest of the year for much of New England.

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