Thursday, March 25, 2010

Winter makes a brief return but will fade quickly by late next week

Cold air has made its southward push in time for the weekend and a brief period of snow will whiten the mountain by Friday first tracks. The weekend however will be a dry one and will be preceded by a rare day of below freezing temperatures (Friday) and single digit temperatures in the morning Saturday. Light winds and full sunshine during the day Saturday should allow for a rapid recovery and slightly above freezing temperatures by Saturday afternoon. Sunday morning will be considerably warmer and the day should feature more clouds but relatively light winds and temperatures slightly above freezing during the afternoon hours.

As one of the warmer and snowless March's I can remember moves forward, the SCWB updates have gotten more sporadic but we continue (consistent with the last update) to watch a weather system on Monday. It is a potent southern branch piece of jet energy which will exit the central Rockies Sunday and make its way to the east coast by Monday. Its track is favorable for some MRG powder but the amount of cold air remains a question. The European model indicates a rather stale supply of cold air and thus limits the accumulating snow to the high elevations of the Green Mountains and the snow itself would be of the wetter variety. The American GFS model indicates that a fresher surge of cold air will become entrained in this system and we would thus look forward to several inches of powder across the entire span of the mountain Monday. The differences between the two models might seem small but have huge consequences. It involves a small piece of energy in the polar jet, a branch of the jet which has largely been confined to Canada this month. The GFS model however allows some arctic air from this branch of the jet to get involved in Monday's system while the European simply confines all the polar jet energy to the north. We can settle for a compromise for it too would yield snow on Monday.

If Monday's system fails to materialize it will be lights on the the winter. Not to say we can't get more snow in Vermont come later in April but the thaw that is to come by late next week will be massive. It will result from ridging in the Central Pacific and unsettled weather across the west. This will allow a Bermuda high to form and the warm air to surge northward. And when I say warm I mean "warm" not "mild". Temperatures in the valley locations will surge to 70 degrees and beyond across the low lying areas by late next week and into the weekend. It will make for incredible spring skiing so long as the snow survives but those temperatures will obliterate the base and likely put an end to the MRG season in short order. I would take advantage of the warm temps early while the snow lasts. It will also be a terrific time to head up to Tuckermans Ravine as there should be several days of fantastic visibility and tolerable winds to accompany the soft snow.

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