Monday, February 8, 2021

Some snow on Tuesday but generally just run of the mill cold weather through Friday with a slight chance for a storm over the holiday weekend

Two snowfall over-performances over the past 72 hours have left the mountain in magnificent shape as we enter the extended stretch of cold weather. The first big one on Friday night could not have been a better weekend gift and a 2nd, but smaller 3-4 inch dose Sunday night was a nice refresher for a cold Monday. The snow is also quite welcome in light of the fact that the forecast for the week has gotten drier with the jet stream looking a little flatter. Arctic air is bleeding south in eastern North America as opposed to the all-out invasion and the pattern is getting a bit of push-back from a persistent southeast ridge. The arctic air will clearly win the battle for New England this week but for the purposes of snowfall, it would have been better if the mild air could have pushed far enough north late this week to allow for a big dose of overrunning snow. This is still a small possibility but the late week forecast does look drier, with much of this action farther south. In spite of that, the next two weeks hardly looks boring and includes another dose of snowfall Tuesday. 

The snowfall producing weather system Tuesday could have been more robust but the polar jet is speeding this sucker along before it gets the chance to attain any strength. All that said, the storm is strong enough to bring both clouds and snow to the MRV Tuesday, a steady light snow in fact, beginning right around dawn and continuing intermittently well into the afternoon. This looks like another 2-3 inch snowfall to me with temperatures hovering in the high teens. The more benign nature of this system will allow winds to be a bit lighter (around 10 mph), with some stronger gusts at the summits as always. 

As mentioned, the forecast does look drier late in the week with the ongoing fight between the core of the arctic cold farther northeast and the milder air to our southeast waging their battle farther south. With the polar jet now a dominant force on the weather map, it becomes more difficult to get a great handle on any potential weather system more than a few days out. You might think you have a good idea how a storm might play out and dramatic changes show up in the forecast data one day later. This has already happened quite a bit the last several days and I expect it to continue. I don't expect any such forecast change to impact Wednesday into early Thursday. This period is likely to start with a few flurries (early Wednesday) before clouds give way to some sunshine. We can then expect the first of what should be several sub-zero overnights Wednesday night. We will have to keep an eye on all that overrunning moisture late in the week and see if it can work its way far enough north to impact northern Vermont. Some of the forecast data is still hinting that a small amount could even though the trend has been drier. 

The Saturday-Sunday part of the upcoming holiday weekend continue to look cold in Vermont as we've discussed but less extreme and more or less a continuation of what we will have already experienced through much of the rest of the work week (teens and low 20's for high's and near zero for lows). The move toward a less extreme version of cold is an important change for another reason. With the core of the coldest temperatures remaining west of the Great Lakes (at least early in the weekend), and the southeast ridge remaining a force in the jet stream configuration, the door continues to be ajar for a storm. We've obviously seen the trend toward the flatter waves this week and that could certainly occur again this weekend, but it doesn't take a big ripple to amplify the pattern in a big way. Very often it's just a matter of timing. Such is the case this weekend when there are  indications that a system moving out of the southern Rockies will take much of that lingering sub-tropical moisture in the southeast and turn it all into a sizable east coast storm. As mentioned, this will case where forecast data will rapidly evolve in terms of how they handle this storm. When it comes to the polar jet, small errors in the initial handling of a storm can have big consequences further out in time, a component of chaos theory illustrated in the form of actual weather. 

Our President's Day holiday Monday continues to look very cold (even as Saturday and Sunday move toward less cold). The potential for -10 degree readings on both Monday and Tuesday mornings remains. Thereafter, temperatures are indicated to moderate at varying speeds depending on what ensemble package you are inclined to believe. I am inclined to believe that arctic air will remain a force but without the proximity of a polar vortex allowing for the continuation of below normal temperatures through next week without suppressing the storminess.

It's an exciting time to be a winter weather enthusiast and an exciting pattern, but a challenging and very fluid one as far as trying to predict specifics. 



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