Currently: You can call today the calm before the storm, as high pressure was lined up along the I 95 corridor. Our storm was over IA and MN.
Tonight: Another nice night. With warm air advection, I'll go a couple degrees warmer than guidance. Lows should generally be in the 30s.
Tomorrow: Generally increasing clouds. Not much precip yet. Although I do have a 30% or so chance of showers for the SW 1/2 of the state starting in mid afternoon, basically W of 91 and S of 84. Steady rain should hold off everywhere until after dark. Winds should steadily increase during the day, becoming breezy by afternoon and windy by dark. Even if I slice a few degs off temp guidance, highs still get to the mid 50s, so it's a very warm day across the state.
The following NWS hazards are in effect: A flood watch is in effect for Litchfield County. A High Wind Watch is in effect for: Srn Fairfield, Srn New Haven, and all of Middlesex, New London, Tolland, and Windham Counties. In between, generally along the I 84 corridor from Danbury to Hartford, no hazards are in effect. However, these areas will also likely get at least wind advisories and urban flood advisories as the storm unfolds.
Let's go through the hazards. First, there will not be any more rain in Litchfield County than anywhere else in the state. The reason for the Flood Watch there and nowhere else is that there is more snowcover there and the ground is frozen. The warmish weather the past few days has helped us, in that the ground has unfrozen a bit, which should minimize the flooding threat and allow for more runoff.
Winds should gust 55-65 MPH throughout the state from later tomorrow night into early Friday morning. If we get any thunderstorms (the chance is very low for most of the state, but not zero), even higher gusts could get mixed down. Up in Litchfield County, if they can retain snowcover, the wind risk will be quite a bit lower, because the snowcover would create a low-level temp inversion, which would significantly lower the wind risk.
Rainfall amounts should be a solid two to three inches. I am using a small range, because there is really very good agreement amongst the models. In fact, when comparing the GFS to the NBM, the total is nearly exactly the same. When agreement is that good, you have to ride it.
So, to summarize, a very high-impact storm is set to impact the area. Widespread power outages and travel difficulties are expected and unfortunately, this is going to hit at a very inpportune time. But at least Santa will get a fast ride back to the North Pole on those southerly winds!
Temperatures tomorrow night will not move very much at all, and may even rise a bit before beginning to fall before dawn. This all depends on the timing of first the warm front and then the cold front. Needless to say, I went well above temp guidance for tomorrow night's temps.
For Friday, Christmas Day, cold air will pour into the area, on gusty, but lighter NW winds. There is also the chance of a flurry or maybe even briefly heavier snow squall, as a combination of unstable air aloft, strong cold air advection, and streamers from the lakes, generate a possibility of some snow showers making it down to our area. As usual, the most favored areas are the NW hills. Went below guidance by as much as 10 degrees for temps, since highs will be in the morning, and temps fall, possibly rapidly, thru the day. Look for temps to fall into the 30s during the day.
Long Term: A fairly quiet period here. Of course, the next major storm probably affects the state right in time for New Years celebrations, but we'll leave that out of the fcst, since it's more than 7 days out, and let later crews refine that, as we go along in time.
For the weekend after Christmas, I chopped a couple deg off temp guidance for Sat, since there will still be good cold air advection in place. Highs should only be in the low 30s, despite a good deal of sun.
I went close to temp guidance for Sun, as advection is nearly zero. Clouds should increase ahead of the next sys, which right now does not look to be a big deal. It looks to be a clipper passing to our N, with either no or very late coastal development. But we'll keep an eye on it, just in case things change. As far as Sunday, it's a fairly nice day, albeit chilly, with highs in the mid to upper 30s.
Now for that next system, I already pretty much covered its evolution. Right now, it looks like a quick burst of mostly light precip centered around midday Mon, maybe lingering into the aftn across far NE CT. It also looks like it should be all rain, but soundings are close, and some sleet could mix in far N. We'll keep an eye on it in case it trends colder. I chopped a few deg off temp guidance with clouds and light precip, but even so, highs reach the low 40s, so most likely looking at all rain.
For Tuesday, fair and cold. I went a few deg below temp guidance, with more cold air advection. Despite sun, highs only 30-35.
For Wed, continued cold, with increasing clouds ahead of the next sys. Highs in the low 30s.
Long Range: Not a lot of time to spend on this section today, but the pattern continues cold and stormy with lots of high-latitude blocking. It's hard not to like that pattern if you like wintry wx!
Now, let's take a graphical look at some systems that will affect the area this week. I'll focus on tomorrow's system and a brief map of our clipper for Monday. On this map, valid midnight tomorrow night, you can see the very heavy moisture headed for CT. Underneath that moisture is where the high winds and dangerous wx will be colocated.