Currently: High pressure currently right along the eastern seaboard is keeping the state cold but dry today.
NWS HAZARDS: A Winter Storm Watch is in effect for the Southern tier of counties, as well a Eastern CT. This is where the highest chances of significant or greater snowfall exist.
Tonight: Temps prob don't fall all that much during the night, due to the combo of SW flow ahead of a cold front and increasing clouds. I went quite a bit above guidance on temps. I think most places will be in the upper 20s at dawn tomorrow. HRRR hints at some flurries getting into our Western zones by dawn, but I kept the night dry. If five snow flakes fall, it does not change the gist of the fcst.
Tomorrow: Short range models, in general, have become more aggressive w/pcpn along and behind a cold front tomorrow. In fact, it would not surprise me if many places see at least a whitening during the day tomorrow. However, I am not going to focus much on accumulations tomorrow for two reasons. First, the "main show" is not tomorrow. Secondly, pcpn will likely be showery in nature, so it could be a day where someone sees an inch and someone does not see a flake. I do have chance POPs for snow showers in the fcst, and w/a cold ground, a few slick spots are possible. Pay attn to any SPS from NWS tomorrow in isolated heavier snow showers. Just as I went above guidance tonight, I went below guidance tomorrow. Guidance is biased toward "temps have to be warmer during the day than at night", even though there are cases when that is simply not true. I think temps largely stay steady tomorrow and begin falling during the afternoon.
Now for the fun part... First of all, as I normally like to do, I want to start this section of the disc off w/a little model roundup.
One thing to look for... many of the computer models that show the higher snowfall totals show the cold frontal snow phasing right into the storm, which energizes the system and tugs it further west. There would be very little stopping between the cold frontal snow and the coastal snows if that happens. The GFS model, in particular, keeps these two entities separate. So we may be able to have a good idea which way this is going by observing radar trends tomorrow evening.
Another concern is winds. Obviously, the closer storm would mean stronger winds. If the stronger models verify, blizzard conditions would be possible for at least the Eastern half of the state. Stay tuned to products from SCTWX and the NWS for any potential blizzard warnings.
Guidance temps on Sat are already cold and I trended them a bit colder due to clouds, northerly winds and precipitation falling. This will be a cold snowstorm and, unless there is an enormous change in guidance, there is no concern of any mixed precipitation types. Temps on Sat will likely struggle to get much above 20 degrees!
Long Term (Sun and beyond): Fortunately, most of the long term is quiet. In fact, our next precipitation event is not slated until the last day of this fcst period.
So I'll quickly go thru most of the days in the long term.
For Sunday, it looks like temp guidance already has snowcover factored into it, so I followed it closely. A sunny and cold day, with highs in the upper 20s. Winds could still be gusty behind our storm the first half of the day.
For Monday, sunny and we'll start the trend of getting a bit warmer each day. Guidance once again looks fine, so high temps should be 30-35.
For Tuesday, I did trend guidance down ever so subtly. Guidance has a habit to lose snowcover, and unless the GFS verifies, or this goes even further E than that, we'll have snowcover Tue. So I tweaked guidance down just a bit. Look for highs in the upper 30s, except mid 30s in the NW hiills.
For Wednesday, i went quite a bit below guidance. The air mass is much warmer, but you'll have increasing clouds with an onshore flow, off the cold LI sound. So low 40s should do it for highs.
For Thursday, the next storm system will affect the area. This storm will track well to our west, up the Great Lakes, so this looks like an all-rain event everywhere. For now, since we'll have a warm surge ahead of a front, guidance was followed, with statewide highs near 50 degrees. If the heavy rain that some models are advertising w/that comes to fruition on a snowcovered and mostly frozen ground, there could be some flooding concerns. But it is way too early to speculate on that. Behind that storm, cold air rushes in and winds pick up.
The long range looks colder and Feb could turn out to be a stormy month! I have a feeling we'll be doing a few more of these type of discos in the next month or so!
In addition to the snow map that will be posted, I'll leave you with two model graphics- one of the GFS, and one of the ECMWF, just to give you an idea of how far apart the models truly are. This is a bit disconcerting to see this close in, to say the least! Notice how on the GFS, CT has light snow falling, but nearly all the heavy moisture is in RI, E MA, and largely offshore. The ECMWF, on the other hand, has heavy precip covering all but NW CT, and moderate precip there. Please do not pay attn to the color ont the ECMWF graphic. It is snow, that product just does not do precip type.