Just How Close Will it Get?

This is the storm that refuses to die. For most of Connecticut the storm is basically a non-event with no snow expected at all. In southeastern parts of the state it’s possible that the storm backs in just enough to produce a quick burst of light snow.

Areas further east like the South Shore of Boston and Cape Cod now may actually get hit by a decent thump of snow. The SREF and GEFS have lead the way showing the potential for this storm to come a bit closer than forecasted in the last day or so. Keep in mind this is after or medium range models totally backed away from this storm impacting us at all. What a long and strange trip it’s been with this storm.

Here’s the 00z NAM forecast precipitation. The light blue is >0.1″ with and the dark green is >1″ of precipitation. The NAM is likely too robust with the northwest extent of snow but it has continued to push west.

I’d say the odds of an inch or two of snow in southeastern Connecticut are about 25% but the rest of the state should get by with flurries at the worst. Never say never but right now it would take something close to a miracle to get a more significant (say 4 or 6″ snow) back into the Connecticut River Valley.

This weather pattern has been raising hell with our computer models. A fast flow coupled by an extreme block in the northern Latitudes complete with a retrograding polar vortex make this a very unusual and anomalous pattern that is difficult for the models to resolve.

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Snow? Maybe? Finally?

With a monsoon drenching New England this evening and a snowbowl on TV in Chicago I’ve got snow on the mind. The European computer model has been insisting on developing a major nor’easter next Saturday and Sunday. The GFS model shows virtually no storm next weekend. The GFS and Euro ensembles are all over the place but in general are in between the 2 operational models.

12z Euro 500mb Forecast Valid 12z Saturday

The Euro has 2 features worth watching. #1 is a disturbance in the jet stream moving across Texas and Louisiana. Feature #2 is a closed low (the same one that will be over the northeast all week long) splitting up with an intense secondary low developing over the western Great Lakes.

12z Euro Surface Forecast Valid 12z Sunday

The 12z Euro phases features 1 and 2 and results in a major nor’easter or blizzard for New England and the Mid Atlantic.  If this model verified 12″-20″ of snow would be likely along with storm force winds near the coast. This is, by far, the most extreme solution the models have been printing out over the last couple days.

On the other end of the spectrum are recent runs of the GFS. It’s important to note the GFS is not as good of a model as the Euro. Still the disparity in solutions is so substantial it’s hard to run with one over the other. As is the case most of the time the truth probably lies in the middle.

12z GFS 500mb Forecast Valid 12z Saturday

The GFS keeps the closed low strong and in tact over New England and acts as a giant block keeping any storminess way south and east. In addition the southern stream disturbance (labeled #1 in the first image) is extremely weak on the GFS. It’s barely noticeable and not enough to phase especially given the setup over the Great Lakes.

What’s going to happen? It’s really hard to say. The GFS and Euro ensembles are definitely closer to the op Euro than the op GFS run. They do have a storm developing off the coast but not nearly as close to us as the Euro. The pattern does look much more favorable than we’ve seen in recent weeks to get a storm to develop. The issue is going to be getting a strong enough southern stream disturbance and getting the closed low over New England to “spread out” enough to allow something to phase and come north.

Snow for the Mountains, Cold Elsewhere

A large low pressure system is part of a major block in the northern Hemisphere that extends from the northeast US through western Europe.  A series of storms will develop around this upper level low but will miss southern New England. Downeast Maine and southern Quebec will be hit with snow over the coming days from these storms and a persistent northwest wind along with waves of moisture and lift will be sufficient for a major upslope snow event in the Green Mountains of Vermont.

Though the bulk of the snow will be across northern Vermont, central and southern areas above 2500 feet will see some flying on and off from Saturday through Tuesday. Generally 2″-4″ is expected for most elevated areas though the higher elevations and areas that tend to get more upslope snow (like Killington) could pick up 4″-8″+ of snow in this long duration event.

For areas not getting snow (like most of southern New England) an unseasonably cold and cloudy airmass will settle in. Periods of flurries are possible but they won’t amount to much. Temperatures will stay in the 30s for many areas though the valley locations and shoreline will be nearly 40. Temperatures will slowly drop through the middle of next week where 30s will be the rule everywhere for daytime highs.

Our next storm threat appears to be in the 12/13-12/14 period as the block relaxes some and the storm track energizes and changes. This could turn into a winter storm for most of us… stay tuned!