Currently: Cold front is now well East of the area with bombing low pressure located over Boston. This low, combined with arriving high pressure, is responsible for the very windy weather across the state today.
Tonight: Temperatures plummet as cold air races in. Winds diminish after 10 PM or so, but it will still be windy all night and even into tomorrow morning, with gusts in the 35 to 40 MPH range. But the threat for 50 MPH winds will end. Guidance temperatures are generally accepted, with lows ranging from the upper teens to near 20.. There should not be too much variation tonight, given strong winds and a well-mixed atmosphere.
Tomorrow: Much colder. Winds gradually diminish, although it will likely still be windy for the first hal of the day, but not as windy as today. Guidance is in remarkably great agreement. An old forecasting convention says that when all three sets of guidance are within a degree of each other, run with it, because it's hard to do better. So in this case, that's what I'll do! Highs should range 25-30.
Tomorrow Night/Sat: We'll radiate well tomorrow night with clear skies. However, clouds do increase, so for this moment, I prefer to go a couple degrees above guidance. Even so, this yields very cold low temperatures, from 5 to 15 degrees or so. Along the SE Coast, toward GON, temperatures will probably stay in the upper teens. More on that area in a minute...
Saturday is the period of interest here. Snow should develop across the entire state during the mid to late afternoon hours. This is not a long-duration event. The entire event is really only about six hours. With a southerly flow, the immediate south coast will probably change to rain. In these areas, expect a coating to two inches of snow, with the two inches more likely in SW CT and the coating more likely in SE CT. For most of the rest of the state, snow will fall briefly heavily. By the time it gets warm enough to rain, most of the precipitation will have ended. Expect generally two to four inches in these areas, with the four most likely in elevated areas. I am not very concerned about sleet. Model text soundings are solidly uniform, so there is no warm layer there. In addition, an old meteorological trick is to check the thicknesses. Sometimes, if thicknesses get very high, even though all text layers appear below freezing, it's a warning sign that there's a warm layer in there somewhere, probably at a layer that text does not "see". However, thicknesses are low, so this is not a concern, I do have a concern for lingering freezing drizzle along and north of I 84 Saturday night. Once forcing vacates the area, ice nuclei cannot form to support snow flakes and light rain droplets fall. North of 84, temperatures should remain below freezing, so freezing drizzle will be possible.
One other quick note: Due to the fast moving nature of this system, as well as the very dry air to start off, this is not a high QPF event. Therefore, I do not expect any large totals, even in areas that stay all snow.
Long Term (Sunday through next Thursday): The main highlight of the long term is prolonged cold weather.
For Sunday, Breezy with clearing skies behind the storm. Expect wind gusts to 30 MPH most of the day, with cold air advection. Could be one of those days where temps spike up for a couple hours after the sun comes out, then level off or slowly fall. As is typically the case, I don't think the GFS MOS is doing a good job with cold air advection. Therefore, I'll shave off 3-5 degrees. Expect highs generally 35 to 40 degrees, perhaps a bit cooler in the NW hills.
On Monday, winter cold. Should be mostly precipitation-free, but an afternoon flurry cannot be ruled out, especially up north as another cold front moves through. With the cold air mass in place, I'll shop a couple degrees off guidance and call for highs within a couple degrees of the freezing mark.
For Tuesday, with cold air advection and fresh Arctic air in place, I'll do my usual trick of cutting 3-5 degrees off temperature guidance. Expect high temperatures only around 20 degrees. In addition, it will be breezy, so it will feel even colder! Again, I am not expecting any precipitation, but an afternoon flurry cannot be ruled out, especially up north.
For Wednesday, temperature guidance looks good, as the air mass settles into the region. No major modifications have been made to the guidance, except a tweek here or there. Expect high temperatures only in the low 20s!
Thursday will continue to be very cold. Once again, temperature guidance looks fine and is accepted. It should bump up a couple of degrees, as the core of the Arctic air moves east. Even so, it will still be very cold. Expect highs in the mid to upper20s.
Looking into the long range, I see no signs of the cold temperature abating as we get into the long range. In addition, the southern jet stream looks to become increasingly active. This would generate a stormy pattern to go along with the cold! This should bring smiles to the faces of winter weather lovers! For those who don't like winter weather, you just had two weeks of spring in January!
Now, let's look at some graphical images of weather systems slated to affect the area in the coming week! Since we only have one real system, I'll post Saturday's snowstorm map, then we'll go into Wednesday morning's low temperatures, as that should be the coldest day of the cold snap, at least until the next cold snap!
This map is valid Saturday around dinner time. Precipitation, mainly snow, except maybe not right along Long Island Sound, has overspread the state by that time. It is hard to take any model map perfectly literally. However, if this map verifies literally, one of the 4" locations might very well be somewhere between Waterbury and the NW Hills. That would not be inconceivable, as that area generally does the best in this setup anyway.