Sunday, December 30, 2018

Possible phased southern stream system late in the week offers potential following a sleet/snow/ice conglomeration on New Years Day

The big picture outlook for January across much of the lower North American continent continues to trend further away from any serious chill and much of the central part of the United States will repeated visits from our friend El Torchy. New England appears well positioned to avoid large chunks of the this warm onslaught though I certainly would prefer a somewhat different jet configuration and a bit more arctic air at our disposal over the next two weeks and beyond. We have some good news on the snow side however and both pieces of news have to do with weather that will occur over the next week.

Our New Years Day system won't bring back the glory days of late November but it appears to be a solid base building event. Please excuse the prior post as I appeared to have my days and holidays mismatched and therefore gave an inaccurate version of the event timeline. New Years eve will indeed see generally cloudy skies with temperatures climbing from a morning low in the teens to afternoon readings up above freezing. Precipitation arrives just in time for 2019 and should arrive in the form of mostly snow with a bit of sleet mixed in. We are certainly capable of seeing some decent snowfall rates for a couple of hours before precipitation changes to mostly sleet before daybreak on New Years Day and eventually freezing rain and a bit of plain rain during the morning. Fear not however, though we aren't getting much in the way of powder, more of the 2-5 sleet/snow mash, we won't melt much of it on New Years Day. By the end of the day, much colder air will be arriving along with some snow flurries and what we hope will be a solid base to build upon down the road. If you are a particularly hungry powder hound and feel like venturing up toward the Canadian Border, Jay Peak will receive mostly snow and only a little sleet out of the New Years Day event (and no freezing rain) and certainly a healthier accumulation of around 6 inches. Go further north to Montreal and it's all powder and a very cold storm.

By the morning of January 2nd, temperatures will be back in single digit territory as will some sunshine and afternoon readings will only be in the teens. This airmass appeared quite formidable about a week ago but will have modified substantially by the it reaches New England and will continue to modify on Thursday Jan 3rd and Friday Jan 4th. Meanwhile the southern branch of the jet stream will continue to operate. It never wants to feel neglected during an El Nino winter so I must apologize failing to acknowledge its prominence. Our potential late-week system did in fact get a mention but certainly not a respectable one because there are strong indications that this will become a phased system by Thursday evening and a big precipitation producer by Thursday Night into Friday across New England. As I mentioned the cold is decaying by late in the week and rapidly so but the track of this storm, if it can choose an optimal course could deliver for Friday January 4th and into the weekend.  I won't promise all powder and I can't even promise all snow yet but the storm certainly has my attention given our snow-starved status. This is the type of event that could deliver a foot or more of the good stuff so stay tuned and think positive thoughts.

We then have to contend with the ever-enhancing reality that January just isn't going to deliver much in the way of persistent cold weather this year. The PNA structure which looked so promising 4-5 days ago has disintegrated and most importantly, we simply can't shut down that pesky and strengthy Pacific jet stream. The various longer range ensembles remain at odds with what happens in the Pacific over the next 2-3 weeks but it doesn't appear likely that two key things will happen in that time frame. 1) The MJO will fully cycle into more favorable North American cold weather phases and weaken at least somewhat from its current strength 2) The development of a large scale high latitude blocking mechanism to counter the strengthy Pacific Jet and bring arctic cold southward.

We will likely have to make the best out of a marginal pattern and there is certainly hope we can do that this week. We are likely to get at least one mild day this upcoming weekend (Jan 5th-6th) before we get modestly chilly for a time next week. Yes, we are certainly capable of getting some additional snow in the January 7th-10th time frame but I can't promise any big stretches of sub-freezing temperatures though I think much of the warmth in this pattern will hit the central U.S. much harder than New England, milder air is certainly capable of reaching Vermont for shorter stretches of time




2 comments:

crypto phone support said...
This comment has been removed by a blog administrator.
crypto phone support said...
This comment has been removed by a blog administrator.