Wednesday, January 12, 2022

MLK storm now very likely though track is still uncertain with favorable pattern now firmly in control through end of month

So much winter weather to discuss in this update with a favorable pattern now firmly in control through the duration of the month. For good reason, we got our eyes fixed on the potential storm on MLK day but there's plenty of weather before that worth knowing about. Arctic air has retreated into eastern Canada but is expected to slam into interior New England again on Friday. Clouds and some very sporadic very light snow can be expected for Thursday with comfortable temperature readings and tolerable wind speeds. Snow will intensify just enough for a light accumulation late Thursday or Thursday evening as the clash between a big storm well offshore and a strong arctic high in Ontario strengthens. That arctic chill will plunge directly into Vermont on Friday and with some very strong northerly winds that will only increase as the day goes on. Temperatures will start in the high teens and likely end the day in the single numbers and with well below zero wind chills. There have been stronger areas of arctic cold to impact Vermont, but when cold enters the state directly from Quebec, it can be especially intense and since this surge is accompanied by ferocious winds, especially at the summit, it is certainly worth nothing. Expect actual temps to be close to -10 Saturday morning with wind gusts reaching 40 mph or more at the summits. I don't make any calls on wind holds since individual lifts can be overly sensitive to certain wind directions but I would not be surprised to see a few. Winds will diminish rapidly Saturday night and a calm day on Sunday will make it feel dramatically warmer. Saturday afternoon temps are likely to stay below zero with wind and Sunday will be closer to 15 with some sunshine and hardly any wind. We still expect little snowfall through Sunday except for perhaps an inch or two late Thursday and whatever falls then will become very compressed and windblown by midday Friday. 

We have broken many snow droughts over the years on MLK day. Off the top of my head I remember significant snow occurring in 2007, 2009, 2015, 2019 and last year so it might be a little matchup between destiny and a recent run of bad luck.  In the case of this year, the blog has, for a while now, made mention of the storm potential during this period, but model data was intent on taking this action offshore when the last update was posted. Since then, there has been a dramatic shift northwest with a storm that looks like a southern streamer, but actually enters the continent in coastal BC. This storm looks dramatically more amplified when it begins to interact with the Atlantic Ocean after already entraining substantial amounts of moisture from the Gulf of Mexico. By late Sunday, situation appears like a classic "Miller A" noreaster with an already strong storm getting another charge from some incoming polar energy. Though the slightly negative NAO has certainly helped with the recent trend, the storm is still a fast mover and the track has not yet been set. The northwest shift has been so dramatic over the last 36 hours that we are now asking it to stop. Several operational models are actually taking the storm west of what we would consider an optimal track, which would limit our snowfall to more disappointing range. Recent ensemble data has begun to exhibit some consistency however (of a fairly optimal track) and I thus cautiously optimistic. We need to fully iron out some of  the wrinkles in the forecast data before many details become clear, but it does appear that it will stay dry through Sunday evening with snow arriving Monday morning. From that point, we need the storm track to pass between Boston and the Cape for snowfall totals to reach a foot-plus. A track west of Boston and we will likely see a thump of snow, maybe even some sleet and then a dry slot and if the storm stays east of the Cape then we start to limit available moisture. 

Behind the storm we can expect some snow showers Monday night and a few days of comfortable temperatures before another surge of colder weather arrives sometime late in the week. This next surge of cold around the Thursday the 20th time frame is also the next chance for some snow. A big surge of arctic air is then expected across all of eastern North America between January 22 (Saturday) and January 27th. It's been a while but we finally got a favorable Pacific jet to align with a ridge (+PNA regime) in western North America. It will mean some big time arctic chill and it also means that we shift the storm track south. New snowfall will have to come from more moisture-starved clippers and limited terrain enhanced snow.

1 comment:

Shemp said...

The NEK could use 🦶🦶 of natural snow. Like all areas🙏