Currently: A stationary front was just south of the state, with a low pressure system right over NYC. Another cold front was approaching from the west, and is currently over NW PA/W NYS. As this front approaches, it will slow and stall, as it encounters resistance from the Bermuda ridge. Where it stalls and when will play a big role in our wx. Unfortunately, this is a fairly new development, so there hasn't been much to look for, in terms of trends. Meanwhile, TS Isaias was near Punta Cana. This could be a player in our wx down the road.
Tonight: I think we're largely dry until midnight. Looking at current radar, not a whole lot is going on. There is one rogue cell in NY that may approach the far NW corner of the state. Other than that, radar is quiet. If an LI Sound breeze can develop in the next couple hrs, look for some initiation there, like what's happening along the NJ shore right now. Otherwise, there is an increasing chance of showers and thunderstorms after midnight, mainly across SW CT. So, sct to nmrs t-storms across Fairfield County after midnight, but the rest of the state should be dry xcpt a vry isolated cell here or there. As for temps, w/clouds in abundance and no real cold air advection, I went a few deg above temp guidance. Xpct lows only ard 70- a very muggy nite.
Tomorrow: A very difficult forecast and this is a day one forecast. It all comes down to where the front stalls. For now, and I hate doing this on day 1, because this is something I do on day 4 and beyond usually, I'll go sct tstorms most of the state, w/ltl or nothing far SE. Even if the front does go thru, I think there is enough instability leftover to generate a few cells, mainly before 3 PM or so. As far as temps, again I hate doing this on day 1, but I hv very low confidence. The air mass supports that if any sun were present, temps could soar, even if only briefly. On the other hand, if it stays cloudy and/or rainy most of the day, temps would be much cooler. Therefore, I'll go cls to gdnc, and this yields high temps ard 80.
Tomorrow night/Sat: I am going to try to continue the theme of keeping Sat dry. For now, I will do this. But for purposes of informing everyone, I will say that there has been a trend to stall the front and further N than before. Doing this would paint a much stormier picture for Sat. Because the models are not there yet, and because I do not want to make drastic changes to the already existing forecast, I'll keep Sat dry for now. But just keep in mind that this could change, based on today's modeling trends. As for temps, I'll stay close to guidance, but given a hunch that it will probably be more cloudy than fcst if anything, I'll go a deg cooler here and there. Xpct highs in the mid 80s.
Long Term (Sun and beyond): Obviously, the main focal point of the long term is the track and evolution of TS Isaias. However, even without direct effects from Isaias, it is going to be very rainy. Obviously some NBM members are going to be contaminated by direct hits from Isaias, but the NBM precipitation avg has actually risen and is now well over 4 inches for a good part of the state for the week. So with or without Isaias, it is pbly a very rainy week coming. There is also the alternative possibility that Isaias does not hit the area, but moisture from the storm gets entrained into our rains, thereby giving the area heavier rain than we would have gotten. I'll get to all this blw.
Current guidance for Sun is showing two rounds of storms. The first one would be early in the morning as the frontal boundary returns north as a warm front. Then instability and the front still being in the area would flare up more t-storms later in the afternoon. I do think the warm front ends up a bit further N than current guidance has it, so I'll go a couple deg warmer on temps. Highs should be in the mid to upper 80s, if this logic is correct.
Mon could wind up fairly dry, especially if the front clears the area on Sun, as I think it will. However, instability lingers, and any lingering frontal boundaries can flare up storms. We'll also need to watch terrain boundaries- such as hills and valleys- where there is a difference in temps, and any breezes off the LI Sound as potential initiation points. Any storms that do dvlp could be prolific rain makers, as they won't move much and the air mass is very moist. As for temps on Mon, I think GFS-based guidance is not handling the moisture well enough and is not showing enough storms. As a result, it's pbly a few degs too warm. So xpct highs on Mon to be 80-85.
If there are any direct impacts from Isaias, they would be on Tue, so we'll talk about Isaias in this part of the disc. The current NHC track of Isaias, which I will display below, would literally be a scrape on the state. This would mean that direct impacts of Isaias would be limited to SE CT, i.e. New London, maybe Middlesex counties. However, models this summer have had a tendency to underdo the strength of the Bermuda Ridge. A perfect example of this is actually what's happening right now: Originally, this cold front was xpctd to sweep right thru the area today and only produce a few isolated shwrs. Now, the front is stalling near the area and definitely has trended tmrw to a wetter fcst and may even impact Sat. If the same trends happen with Isaias, then it, too, will trend W. Although the current track of Isaias would likely spare the state (xcpt the far SE) of direct impacts, it is too early to tell whether or not the mdls may make the same mistake again and trend the storm back to the W.
If we do not see direct impacts from Isaias, then Tue could wind up mostly dry, save for a round of storms in the morning. Much like Mon, any storms would then be focused on boundaries. Now, obviously, if there are direct impacts from Isaias, the fcst would be much wetter, windier, and cooler. For now, I'll split the diff between the very warm GFS and the very cool NBM (which pbly has some members with direct impacts from Isaias). This would mean highs in the mid 80s, for now.
Model consensus for Wed-Thu shows t-storms over the area for much of the time, some with very heavy rain. Even if Isaias is a miss, it could enhance rainfall into our area. In 1996, Hurricane Lili missed the area by 700 miles, yet produced a wide swath of heavy rain, as it injected moisture into a coastal low. A couple more final notes on Iasias: First, it is not a compact storm. TS force winds, per NHC, extend over 300 miles from the center. This would indicate that the actual center could track far from the region and still produce strong effects. Another thing, as pointed out by the NHC this morning, as the storm crosses Hispaniola, the entire structure of the storm could change, which could lead to track and strength errors.
I promised that was the final note on Isaias, but the 12Z ECWMF has just run. It is much further W and stronger than the GFS/NHC tracks. I do not want to go too crazy over one model run, but suffice it to say, the ECMWF would be a VERY high, direct impact from Isaias for the entire state.
Anyway, for Wed and Thu's temps, I went a bit higher than guidance Wed and a bit cooler than guidance Thu, since we could be looking at some onshore flow by then, if some of the modeling is right. This would yield highs in the mid 80s Wed and near 80 Thu.
Obviously, I did not have much time to look into the long range. But one quick glance looks like a continuation of a warm, humid, and stormy pattern.
Now, let's look at a couple graphical images, representing the upcoming threats. First, I'll post the official track from the NHC. Verbatim, this would be a glancing blow. I do not need to rehash the same ideas I already wrote above, but my thoughts are that if there is any correction, it would be W of where this map has it going. And even this map verbatim would produce direct impacts for SE CT.