Currently: A cold front is sprawled out along the E coast from Pensacola, FL, all the way to Eastport, ME. Three low pressure centers are analyzed along the front- one over upstate SC, one near the Jersey shore, and one near Eastport, ME. Another weak low, associated with a trough, was near Ottawa. High pressure stretched out through the Plains. This high will build over our area after the frontal rains clear out.
Tonight: Waves of showers will be possible on and off throughout the night, but should end by dawn. Without much opportunity for real radiational cooling, have generally taken a guidance blend for low temperatures tonight. Expect low temperatures in the 50s throughout the state- low 50s in the cooler spots and upper 50s in the warmer areas.
Tomorrow: Expect slow clearing in the morning, then with convective temperatures being reached in the afternoon, expect cumulus to build. Given those factors, temperatures should wind up very close to guidance- 70 to 75, with a few upper 70s in the CT valley and urban centers.
Tomorrow Night/Fri: An upper level disturbance will move SE out of Canada down into Northern New England. This upper level low could trigger a few light rain showers. Since the system will be moving over Northern New England, the chance will be mostly limited to the NW Hills, with daytime heating. Therefore, there should be a larger than normal gradient in temperatures on Friday. Temperatures south of I 84 should be close to guidance; north of there, temperatures will probably run a degree or two cooler than guidance. So, expect high temperatures to range from the upper 60s in the NW hills, to the mid 70s along the south coast and urban centers.
Long Term (the weekend and beyond): An absolutely beautiful, crisp weekend is on the way. After that, we will get some rain, either from just a warm front, or possibly from whatever remains of Irma.
First, we'll group Saturday through Monday together. These days will be fair with beautiful, albeit crisp, early fall weather. Expect highs on Saturday to range 65-70- very close to guidance. Saturday should be mostly sunny, but it could very well cloud up in the afternoon in the NW Hills, as spokes of upper level energy still rotate around from Canada. There is a very slight chance of a sprinkle in that area, but I'll leave it out of the forecast, due to basically a zero probability of measurable precipitation.
By Sunday, there should be no more upper level energy to worry about, so the entire state should be basking in the sun with a downsloping flow, so I'll go a few degrees higher than guidance and take the entire state, except the NW hills, into the mid 70s, but a few low 70s up in the hills. We'll do the same regarding guidance on Monday and take most of the state to near 80, but with low humidity and plenty of sun. It should be noted that most of the state will be in the 40s for lows over the weekend, with a few of the very cold spots approaching 40 degrees.
Now for Tuesday to Wednesday, there are several track possibilities with Irma... first would be a Florida landfall, followed by a slow decay over the SE, which would result in devastating flooding over most of the SE and little effects up here, other than a gusty NE wind. The other option is a Carolinas landfall. This option then has two subsets of possibilities that could happen thereafter. The first would be that Irma hits the Carolinas from the SE and continues NW and then decays over the Appalachians. This would bring squally weather into the region, with rounds of heavy showers and thunderstorms accompanied by strong winds possible. A final option would be for Irma to make a landfall in the Carolinas and then continue near or up the coast, moving N. This would be the highest impact event for our area, as we would, at the very least, see heavy rain and high winds. At this time, it looks like the first or second options, or a combination of the two, would be the most likely solution. However, it is important to note that this is still in the 6-7 day time frame, and to make a declarative statement this far out would be ridiculous. Even if Irma decays over the SE and has little or no effects on the area, a warm front will still be approaching from the SW, so rain will be possible either way. And with a very large and powerful tropical system to our south, it is likely that at the very least, winds will pick up a bit. As for temperatures, this is also a very tricky forecast. As it is, I'll go near guidance on Tuesday (with the expectation that any precipitation holds off until Tuesday night), which would be temperatures near 80 degrees or so... then I'll go a couple degrees lower than guidance- mid to upper 70s- for Wednesday, with the expectation that rain will fall much of the time. Obviously, a track up the coast would result in much cooler temperatures.
Beyond whatever happens on Tuesday and Wednesday, it is possible we enter a period of above normal (to maybe even much above normal) temperatures from September 15-20, followed by a significant cool down back to below normal (at least that's how I see it right now).
Tropical Wx: It is rare that there are three named hurricanes in the Atlantic Basin at once. However, we officially have three. Irma, we all know about, then in back of Irma, we have Jose. Most modeling suggests Jose would go out to sea. However, some of it is very close to giving CT at least a brush with a tropical system. Being that this is 10+ days out, it is at least close enough to keep our eyes on. It does not appear that Jose will be as strong as Irma. Finally, we have Katia, deep in the Southern GOM. This storm will have no impact on any of the CONUS, but will produce hurricane conditions in the Mexican state of Veracruz.
Now, let's take a look at some of the systems that will be affecting the area in the coming week... how about just a "then and later" with Irma this time.
Here is a look at where Irma is now and the National Hurricane Center's track. Note that today's cone has shifted significantly east of yesterday's, and now takes the center of Irma very near the coast of Florida, before making a sharp turn due North. The key to CT will be where it goes from there, which is still to be determined.