First off, the weekend will be very tranquil and unremarkable weather wise; near normal temperatures tomorrow, warming to above normal on Sunday. It's after Sunday that the weather will take a turn for the more wintry.
Let's start with what we know will happen...
1. A series of storms, which will be explained a bit later, will affect the state. The storms are, in order, a Gulf Low moving up the East Coast, followed by an Alberta Clipper-origin system, then, later in the week, an Alberta Clipper system with an associated Arctic front.
2. The state will likely see at least one light snow event across the entire state, with the potential for more than that everywhere.
3. There will be an Arctic outbreak at the end of the week.
4. We will see flakes flying across the state most of the days between Monday and Friday.
5. It will be windy most of the time, from the pressure gradient associated with the various systems.
These are our "known factors"... however, there are a lot more unknowns than knowns at this time. So let's do this in order.
The first system that could effect the state is a low pressure system ejecting from the Gulf Of Mexico and traveling Northeast, off the United States East Coast. Right now, the GFS and its ensembles, as well as the UKMET, keep this system well Southeast of the area, with no precipitative effects. The SREFs (Short Range Ensemble Forecasts), however, are much further west, showing a moderate hit, especially to the south coast. All in all, there has been a trend westward today, but not a very large one.
Normally, given history, one would ignore the SREFs as "just being the SREFs". However, for whatever reason, the SREFs have had a very good winter so far. They were among the first to correctly identify the westward and stronger trend with the blizzard. They were also among the first to correctly identify the westward trend in today's system. Also, we are in a strong El Nino. In El Ninos, systems originating in the Gulf Of Mexico tend to track further west than originally thought. This has been going on for more than twenty years. Given the above, it would be foolish to totally dismiss this threat...however, given the fact that most of the modeling is well offshore, it would also be foolish to call for a huge storm. It should be noted that if this storm did trend west, the modeling all agrees it would be a very strong system.
Right on its heels is a fairly aggressive Alberta Clipper system will head to the area. Earlier, most of the modeling was digging this clipper well southward, then redeveloping near NC or VA and thus producing a significant or major snowstorm for the state. Most of the modeling has now backed off on that idea, possibly because the two systems are too close to each other. However, there is one notable model- the UKMET- that still favors this scenario. Again in other years, I would completely dismiss this scenario. However, the UKMET has also had a very good winter. So we have two "outlier" models that are performing well.
There are other possibilities, as well... First (and I need to stress that this is HIGHLY unlikely, because too much would have to happen), but it is possible the two lows could phase together, creating a monster, so to speak. To accomplish this, the Alberta Clipper system would have to speed up and the coastal low would have to slow down. Another possibility, which may have a slightly higher (but still low) probability of happening would be for the two systems to pass by, then interact with each other, causing some retrogression, and throwing snow back to the area. To accomplish this, modeled blocking would probably have to intensify more than what's currently being modeled.
Yet another possibility to get snow in the Tuesday-Wednesday timeframe exists, and this is from a system that is only marginally related to the other two. Let's say that none of the "big snow" scenarios pans out- in other words, the Alberta Clipper doesn't have time to redevelop and the coastal goes out to sea. One thing most of the models agree on is that an inverted trough feature will setup, and spread snow to the area. An inverted trough basically happens when you have a storm well offshore, but the upper level flow is aligned so that moisture can get transported inland from that system and produce snow in the area. The problem with these inverted trough features is not predicting their existence (models are in good agreement on this), but they have been known to shift their axis of heaviest precipitation at the last minute and they don't have a long track- they just develop, so you can't track one of them halfway across the country, for example. At any rate, the air mass will be very unstable, and any small development could trigger off a snow shower or squall at virtually any time this week.
This is a VERY LOW confidence forecast. Keep in mind, models have shown wild swings inside 48 hours this winter, and the systems we've been dealing with have been far less complex than the setup for this week. It is a meteorological rule of thumb that more waves in the flow can complicate models and cause them to have a higher than normal error rate. This makes meteorological sense, since what happens to one storm can effect the next, and if a model mishandles one storm, it can certainly mishandle the next. It even makes sense in life, as in when a person has more tasks to do, life becomes more difficult! Picture each of these systems as a "task" for the model to handle. Based on all of this, I wouldn't be surprised if there is a "consensus" to some system and at the last minute, something unexpected happens! Stay tuned, it's going to be a long week!
By Thursday, we should be fairly clear of the systems to affect the area and get a one- day reprieve, with generally fair weather, with below normal temperatures. On Friday, another Alberta Clipper system approaches. Models differ on the exact track of the system. A track further south, like the ECMWF shows, would bring widespread accumulating snows to the state. A further north track would not- but there could be snow squalls along the Arctic frontal passage that this clipper will bring anyway.
President's Day Weekend looks to be very cold, this was one of the "knowns" that I talked about at the top of the discussion. The only differences in models right now is how cold? There is a steep thermal gradient establishing itself across the Northeastern United States. The exact position of this gradient in relationship to Connecticut will determine how cold it gets, but the question is really just very cold or record cold! Either way, it looks cold!
There is actually pretty good model agreement that there is our next potential snowstorm threat right after that weekend, and based on the upper level setup, it could have a high ceiling, but let's get through all the action in the shorter ranges first!
Let's have a look at some maps of the upcoming systems.