Tuesday, February 24, 2015

New pattern coming for March but more snow shoud be the result at least initially

There is some available energy and moisture in the southern branch of the jet stream this week but the pattern has become very suppressed for the back half of February and many would-be storms are staying well to the south of Vermont. We have managed a dose here and there however though Wednesday's dose will amount to the 1-4 ultra fluff variety. Flurries may continue into Thursday but a gigantic arctic high pressure center situated over the Dakotas will keep a large portion of the northern United States on the drier side for late in the week.


The much-discussed pattern change takes shape for the weekend. After a sunny but cold Saturday, the first day of March should bring more seasonable temperatures, perhaps, dare I say 30. Clouds will also be prevalent later in the weekend  and some snow should fall. The nature of this rather disorganized late weekend weather system remains a bit uncertain but it will be the first of many, in what should be a less cold and much stormier weather pattern for the first 10 days of March.


At least for a short time, the mean position of the upper trough will be located across the western United States. Meanwhile, lingering very cold weather Canada will battle it out an emerging area of warmth across Dixie. I think two additional storms (following the Sunday event) will impact the region as a result of this situation. I can't promise both will be all snow but the first, in the midweek time frame, as a good chance to be mostly snow and quite possible significant snow. This midweek storm will finally deliver the Rocky Mountains a big storm before it exits the west and advances toward us Tuesday. Final track, storm intensity and total snowfall remain unclear but the remaining supply of cold in Quebec paired with the healthy push of warm advection thanks to the warmer south are very beneficial for us typically.


There is some disagreement amongst the models in regards to the strength of the chill that follows the Midweek storm. The American Ensembles argue for a very temporary round of extreme cold late in the week while the European suggests a more garden variety shot. Given the way this winter has played out across New England and given the extent of ice and snow across eastern North America, it would not be wise to bet against a short but extreme outbreak of cold in early March; after all, these things are quite common during this part of our winter. The cold should retreat by the weekend and set the stage for what I think will be the next in this series of storm systems. More on that in a subsequent update. In general however, this new pattern will keep the blog busy talking about all kinds of weather. We have almost completed a historic month of weather across Vermont, one which could rival the cold of February 1934. Though March will likely be a little below normal as well, we will be talking about some above freezing weather days in the very near future thanks both to the emergence of this new weather pattern and also due to March's higher sun angle.



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