Tuesday, November 26, 2019

Upcoming week is very active and December 1st and 2nd looks especially interesting

With the seasonal outlook delivered, it is time to quickly shift gears and talk about what is an active looking week of weather even if it's not especially cold. We are about to finish the coldest November so far this century, colder even than last year's Snowvember. Much of the arctic air responsible for this very cold month has retreated an active jet stream is poised to deliver two major weather systems to the east coast, both of which are likely to be elevation sensitive but significant events - especially #2.

The storm responsible for over a foot of snow early Tuesday over portions of the Colorado front range will move northeast toward the eastern Great Lakes bringing a push of milder temperatures up the eastern seaboard. For a time, this milder air appeared also headed for Vermont but a re-aligning polar jet stream in Canada will help turn this storm eastward preventing the state from getting blow-torched. It will be warm enough for precipitation to begin as rain up and down many of the green mountains, even at the highest elevations but as we head toward the evening precipitation will begin changing to snow at the summits. During the overnight hours, we should see some snow even in the lower valleys while the ski areas receive 4-8 inches. Light snow should persist over the high country for a decent portion of Thanksgiving day as well with temperatures just below the freezing mark. This basically means that much of what falls Wednesday night into Thanksgiving Day will be pretty wet, except above at least 3000 feet.

A moderated polar air mass will build across the state late Thursday into Friday drying it out and providing a couple of days of sunshine both Friday and Saturday. Friday will be a bit on the blustery side, Saturday will be relatively calm. Both days should feature temperatures below the freezing mark throughout the day.

While the Thanksgiving event was a storm that originated in the southern Rockies, the storm poised to impact the east coast in the Dec 1-3 time frame is a powerful area of jet energy that will slowly migrate its way into California in the coming days, bringing heavy snow to a huge swath of heavy snow to a broad area of western ski country (both north and south) and proceed into the northern plains this upcoming weekend. Under many circumstances the storm would become a spent force while occluding across the north-central part of the country but the jet stream is poised to re-amplify across the east coast setting the east coast snowfall potential through the roof. The fresh supply of cold air is somewhat lacking, as it often is in early December, but the interior high country is positioned extremely well for a very big event given the right track. We've seen some good consistency from the European model the last several runs which makes me extremely optimistic. The Canadian model is also on board as of midday Tuesday but the American did shift the track of this storm pretty far south. In any case, the event remains 5-6 days off so we can't quite lock it in yet.

Normal early December temperatures will follow in the wake of this storm, whether we get the full impact or not. Some light snow is again possible later in that week.

Glancing toward the middle of December, the pattern does not appear arctic but not torchy either. A positive Arctic Oscillation is likely to keep wintry weather combined to Canada and the far northern latitudes of the US. Fortunately Vermont makes the cut there so wintry conditions remain possible through the 15th .

2 comments:

pog said...

Glad youre back! Have a nice ski season and thanks a lot for the time you put on your blog for us! Way better than weather news we got from television....

peace, love and ski!

pog

Lisa said...

Love you being back on board