Sunday, December 31, 2023

Colder air and potential storms to kick off our 2024

Happy 2024 everyone. Hope your holiday was safe and joyous and I certainly hope the new year brings with it some snowfall. One thing I've learned staring at too many weather maps over the year is to never get too caught in the moment. Model data is fluid and can signal an overly abysmal outcome one day and an amazing one two days later. It can provide a signal, but one needs to boil that down from the persistent noise. On New Year's eve, the afternoon suite of models provided a sensational outlook for Vermont winter weather lovers during the first half of January, but only three days ago the same set of indicators has us shooting blanks, averting much of the snow and struggling to attain the persistent cold we've been waiting for, over the last month. Boiling this "noise"  down, we can certainly conclude that trends over the last 24-48 hours are very positive. We have some concerns, but the weather maps show an abundance of storminess to go along with a much healthier pool of cold to work with on our continent. It's a new year and certainly a new day when it comes to the prevailing weather pattern. 

As promised I think some sunshine returns for New Year's day. A chilly, but seasonable start to 2024 with a clipper system passing too far to our south to provide any chance for snowfall. That same clipper will intensify some out over the ocean and provide a beautiful starry Monday night across Vermont followed by a sun-drenched Tuesday to go along with more sub-freezing temperatures. Clouds will return for Wednesday and it was certainly all of our collective hopes that these clouds would come in advance of the first chance for significant snow coming out of our recent holiday misery. This was the "split flow" storm I had such high hopes for, but the southward advancing polar jet appears to be moving any potential amplification out over the ocean. Still, we have a first and rather healthy batch of cold advancing upon us and some lingering moisture with the associated clipper. Snowfall, albeit light, remains a likely outcome late Wednesday, Wednesday night into Thursday and it should be enough to yield an accumulation of a few inches. The incoming cold certainly rivals the coldest of the season and ensures a very sub-freezing first full weekend of Jan though that won't be the biggest story of that period. 

The 2nd in the series of southern streamers will dominate weather talk in the coming few days. It has an impact date of Jan 7 and 8 (first weekend of Jan), appears more potent, has a supply of antecedent cold air and does not have the trailing polar disturbance to kick if offshore. What makes this storm more certain than others ? It doesn't require a phase or any specific interaction with the polar jet. It will all just down to the track and just how far north this particular system decides to deposit its moisture. There have been some historic nor'easters during super nino winters that have managed to avoid Vermont entirely (looking at you '83 and '16) and that's always a possibility, though the overall jet stream configuration suggests both interior and coastal New Enland are in play. Get ready, this one will be heavily discussed in the coming days. 

Ensembles have been signalling (with lots of noise)  two major themes during the 2nd week of January. Another possible storm around the time of January 9th/10th and a more widespread and sustained outbreak of cold of an uncertain intensity behind this storm. The storm on the 9th/10th is a product of the somewhat problematic Pacific and threatens to amplify the jet too early and too far west. These are the moments when we need some downstream blocking over the Davis Strait or over Greenland to prevent such a storm from charging at the Great Lakes and indeed we have it ! So although such a storm may make a bid to cut well west of New England, it will make every effort to make an energy transfer to the coast. 

And yes we have a more sustained round of cold weather to follow. Even the Pacific was shown to weaken considerably after the 10th allowing the negative AO/NAO combination to do its work in peace. Just the way I like it !

1 comment:

Lisa said...

Happy New Year Josh...This seems a bit more promising Fingers crossed.