Saturday, March 9, 2019

A few inches of snow and maybe some sleet early Sunday, a "corn horn" Thursday and wintry looking official start to spring

The mostly occluded storm that is spinning its way toward into the northern Great Lakes Saturday, and will subsequently push deep into Quebec on Sunday; will, as promised, brings its moisture into the prevailing, but decaying area of cold currently in place across Vermont. Because the storm has already reached maturation, and because of the lack of redevelopment along the coast, this will hardly be a particularly memorable event. Northern Vermont could certainly use a dose of snow however and this system will provide a limited supply of that. Snow should begin around daybreak on Sunday and accumulate 2-4 inches during the morning before precipitation tapers off or perhaps continues as a light freezing drizzle or even plain drizzle. Temperatures will start off the day in the 20's allowing for the snow to be of a more powdery consistency in the morning but then warm toward or even above the freezing mark during the afternoon. Looking at temperature profiles Sunday, the expected precipitation type continues to be a close call. If it comes down hard enough, most of it will be snow, if its lighter than expected we could see more in the way of sleet. My expectation is for some snow in the morning but I did want to throw out the alternative possibility.

Temperatures Sunday night into early Monday appear relatively mild, hovering mostly in the lower to middle 30's under clouds. Across the summits, readings have a better chance of remaining below freezing. As Monday progresses, the storm's original "cool pool" area aloft, better described as simply as an area of instability, will push eastward and encompass northern New England by the evening. There is limited but available moisture with this allowing for a period of snow showers beginning late in the day Monday and persisting into Monday night as temperatures drop into the 20's. An additional few inches of snow is possible with this ahead of a Tuesday which will feature early clouds and some flurries giving way to some limited sunshine and blustery conditions.

Winds will subside by Wednesday and a very strong dose of March sunshine will warm temperatures from the teens well into the 30's, possibly even 40. I can't say for certain if this gets the "corn horn" blowing since sometimes the lower dewpoints prevent that kind of thing when temperatures are confined to the 30's (even if they are above freezing). On Thursday however, readings should surge well into the 40's along with stronger southwesterly breezes. There is some talk of rain in the various forecasts I've looked at Thursday but I think any of that will hold off until Thursday night. Friday will follow as a very mild but cloudy and breezy day with showers likely but no persistent rain.

The colder, positive PNA jet structure will begin to take shape by Saturday March 16 and continue through the spring equinox. Different simulations have shown varying winter weather situations within that time frame so though I can't be specific as to what and when, I can say new snow is likely during the aforementioned period and it's even possible for a rather sizable event. One can certainly hope. 

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