Sunday, February 24, 2019

Wintry weather dominates the upcoming final week of February and big storm offers varying possibilites for first weekend of March

Snow, sleet and a little wet weather prevailed as expected on the last Sunday of February. Mad River Glen and much of the rest of the northern Vermont high country can expect a turn back to snow Sunday evening, possibly enough for a quick inch or two. Snow showers and a few snow squalls are then likely from the pre-dawn hours Monday through the duration of the day. Though the chances for a big accumulation from the terrain enhanced snow appear best north of Stowe, 2-5 inches of the more fluffy but wind-driven stuff is still my guess for MRG. Temperatures on the mountain Monday will remain in the 20's, accompanied by very gusty westerly winds.

Flurries and snow showers will continue through Monday night and temperatures will plummet into the single numbers. Another inch or two of powder is possible by early Tuesday thanks to a more favorable northwest wind. Those winds will remain strong into Tuesday morning but begin to subside as this very cold day progresses. Clearing skies later Tuesday and light winds Tuesday night set the stage for a round of sub-zero temperatures early Wednesday, but some strong late February morning sunshine should allow readings to bounce back into the teens by Wednesday afternoon.

I have to throw some reverse shade at the American GFS model for sticking by the potential for snow Wednesday night while the two other major medium range simulations had all but eliminated that possibility for several days. Though not guaranteed by any stretch, the possibility for a Wednesday night into early Thursday snow has appeared better over the last 36 hours. Not enough moisture for anything epic, but a few inches is what we can hope for.

The cold weather which will be nice enough to dominate much of the upcoming weather week is expected to relent somewhat on March 1st just as the jet stream prepares to undergo a major amplification. There's a weather system involved as well which of course means the possibility of a major league weather system during the first weekend of March. The temperature moderation on Friday, March 1st could be associated with a period of overrunning snow but the possibility for big snow is dependent on the evolution of this potential weekend storm. Like many of its predecessors, there have been indications that the storm becomes too wrapped up across the Midwest and allow way too much warm air to get sucked into the mix for an all snow event. Unlike many of its predecessors, the negative PNA regime will mostly be gone and the amplifying jet stream supports the notion of a much more dynamic coastal low pressure center.  If this storm can successfully transfer its energy to the coast in an efficient and timely manner, it would be reduce the chances for mixed precip and place Vermont in a terrific geographical location for a big dump. Right now this is right on the fence and could go in either direction.

Much like early this week, early next week (March 3-5) will feature cold, wintry weather with the possibility for terrain enhanced snow showers. Without a negative NAO, it is expected to be positive for the next two weeks, it is difficult for departing storms to get hung up for too long across the Maritimes and thus holds down the potential for extended periods of terrain enhanced snow. That said, colder temperatures are expected to prevail through much of the week in question and smaller weather disturbances will bring the possibility for snow at least once. Unfortunately, the pattern is not expected to hold much beyond the time of March 7th. The strong ridging across Alaska is expected to almost completely vanish and there isn't much blocking at high latitudes in the jet stream capable of holding the cold at mid-latitudes over North America beyond that aforementioned date. It would go against much of what has happened over the past few mid March periods but this upcoming mid March might actually feature our first round of more spring-like temperatures though its certainly early to tell for sure.