First off, we will have a weak storm system which will affect southern New England tonight. An area of low pressure will be developing off the coast of the mid-Atlantic and slide to our south and east. At the same time an upper-level shortwave trough will be passing by off to our northwest. This scenario will set the stage for some light snow showers, especially down across CT during the evening/overnight hours. No accumulations are expected, however, some areas could get a coating of snow, especially if the low tracks a little further north.
Perhaps the biggest story over the next several days outside of the storm potential on Saturday will be extreme cold for this time of year. An arctic cold front is expected to pass through southern New England late Wednesday evening and may be accompanied by some snow showers. This will usher in some more cold air. However, on Thursday a much stronger secondary cold front pushes through the region and this will usher in some extreme cold for this time of year. While Wednesday night and Thursday will be quite cold, we feel the brunt of the cold Thursday night, Friday, and Friday night ahead of the next storm system. In fact, computer forecast models are forecasting temperatures at 850mb (around 4500-5000') to be around -20C to -30C 7:00 AM EST Friday morning. That is quite exceptional for this time of year:
This will yield overnight lows Thursday into Friday down into the single digits and perhaps even below-zero across the typical coldest locations. Highs on Friday may even struggle to get out of the low 20's across many places and some spots could fail to reach 20F. In addition to this cold we will have to deal with some pretty strong winds as well so windchill values will make it feel like it is well below-zero at times. By Saturday things begin to change ahead of our next weather system and that looks to pose a bit of a mess, perhaps similar to what we dealt with Sunday night into Monday.
An area of surface low pressure associated with some shortwave energy will be tracking across the Great Lakes late Friday into Friday night. As this occurs, a warm front will begin pushing northward towards southern New England. As the warm front approaches we will see an increase in isentrpic lift associated with the warm front. There are questions, however, with how much moisture we will have in place as the airmass will be quite dry, however, computer forecast models do show some saturation of the atmospheric profile so we may see a period of light snows develop overnight Friday. Given how cold the airmass and ground will be snow will have zero problem sticking. Given how the snows will be low-level produced the flakes should be tiny and we won't see heavy snowfall rates so these won't produce any big totals (maybe 1-2''). The initial surge of warm-air advection at the surface may be rather slow through the first part of Saturday. This is due to the possibility of a wave of low-pressure developing along the warm front:
Given how extreme the cold will be in the lower-levels of the atmosphere the warm-air advection early on will be rather weak as well until the low-level jet begins to increase and that will really accelerate the northward progression of much warmer air. This is huge because this means a much longer time of the atmospheric profile being cold enough ti support snow. With this in mind, while it is too early to throw out snowfall totals, many areas may be able to pick up at least 3-4'' of snow before we begin seeing a transition to sleet, freezing rain, and then plain rain. Areas north of CT into MA have a much higher potential to pick up at least several inches of snow. By early afternoon the low-level jet at 850mb is expected to reach 50-60 knots and this will vastly work to usher in much warmer air, both at the surface and in the lower-levels of the atmosphere:
As we move into Sunday things are looking rather interested ahead of the cold front associated with the low pressure system tracking across the Great Lakes The surge of warmth ahead of the cold front looks quite impressive and temperatures could soar into the 50's to perhaps near 60F overnight Saturday into Sunday. Computer forecast models suggest temperatures at 850mb will approach +10C very early Sunday morning:
This warmth will be very short lasting, however, as the cold front begins moving through during the late morning/early afternoon hours. With the approach of the cold front we could see a period of heavy rainfall and perhaps even some thunder. Once the cold front passes through temperatures will fall back very quickly as lows Sunday night into Monday will only be in the teens across the region.
We will certainly be experiencing some pretty drastic swings in the weather over the next week, especially with regards to temperatures. For snow lovers, its very unfortunate the cold isn't producing snow, however, this is due to the fact that all the storms are tracking well west of us and that is allowing for warmer air to move in ahead of the storms.
Looking long-term there are growing signs that as we approach the Christmas holiday and first part of 2017 we will see a major shift in the overall hemispheric weather pattern and we may enter an average to even much-above average regime temperature wise. This doesn't mean we won't see any sporadic cold shots but does mean overall we will be much warmer. This certainly won't be good news for snow lovers.
Over the next few days as we approach the weekend we should be able to pin down details as to what to expect snowfall wise, whether we'll have issues with freezing rain, and when things transition over to rain.
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