Currently: High pressure stretches from the Appalachians to the Bermuda High. This was producing the hot, humid weather over the area. Our cold front that will end this is up near Toronto.
Tonight: Although most of the night will be dry, I could see a storm late at night as a little backdoor boundary bubbles across the state. I have inserted low chance to slight chance POPs across the area w/this feature. Although most of the state will stay dry, any storms that do develop could produce heavy rain, due to the moist air mass, and will not move much, due to weak steering currents. For temps, I went just a bit below guidance, due to the combo of radiational cooling and perhaps evaporational cooling in areas that get rain. Even so, it's a very warm and muggy night, w/lows only near 70.
Tomorrow: I feel the SPC is underdoing the storm threat. Models have moved up the timing, which means storms could now initiate during the day, which will give the storms more heat to work with. In addition, we'll have very high humidity, contributing to very high CAPE levels. Generally, in the Eastern CONUS, when we have a high CAPE day, we do much better than expected w/severe wx. The key will be how early storms can initiate. If we see storms over CT or to our west in NY state headed this way by 2-4 PM, at least parts of the state should do well. I have inserted likely POPS into the fcst for this timeframe. Now for temps, I went pretty close to guidance, as I think we'll have ample time to bake before the storms arrive. Highs should be in the upper 80s.
Tomorrow Night/Sat: I have likely POPs running thru the night and then taper off to high-end chance POPs thru this period. A line of showers and storms will be ongoing across the state for the first part of the night. After that, it really depends on where the front stalls. Models are not in much agreement as to whether the front stalls near the area or down near the Delmarva, which would have a large impact on pcpn amounts in the area. So for now I have compromised, gradually tapering POPs down to very low by late Sat afternoon. At any rate, it seems prudent to go well below guidance for Sat's temps, as the combo of CAA and pcpn/clouds should keep temps down. Look for steady-state temps only near 70 degrees.
Long Term The main concern in the long-term period is a frontal system and associated coastal low potential right around the middle of the week.
For Sunday, I think we'll probably have a dry day. I do believe the front probably sags S enough to clear us out, at least of moisture. However, clouds should still dominate along w/onshore flow, so temps will not warm much. Guidance doesn't seem to be capturing this too well, so I went way below and have mid to upper 70s for temps. There is a slight chance the front hangs further N. If this happens, then pcpn will need to be added for this period. However, it is my belief at this time that pcpn chances are too low to mention in the fcst.
For Monday, the front returns N as a warm front. Heat and humidity return, but it won't be as bad as today. Guidance does not look too bad, but it usually tends to blast warm fronts thru faster than reality, so I went just a smidge under guidance. Highs generally in the low 80s. Scattered to numerous t-storms too, with the fropa in the afternoon. CAPE is fairly good, so strong storms are not out of the question.
For Tuesday, relatively warm and humid air remains in place. I am not sure if we get quite as warm as guidance. This will depend on wind direction. There could definitely be some onshore flow. So I went a touch below for now. Highs near 80 degrees, maybe 80-85 along the I 91 corridor. I kept it dry as there really is no trigger for storms on Tue.
For Wednesday, a cold front goes through during the morn. I only have widely scattered t-storms w/that feature, as timing is bad. However, many models are now showing the front stalling and a coastal low of sorts forming on it. This would mean chilly wx, as we'd be on the cold side of the front, and rain, heavy at times, w/even a gusty wind. I am not ready to bite wholeheartedly into this scenario yet, since it's a long way out. But it's not hard to imagine, as a front stalls into the Bermuda Ridge and baroclinicity builds between the two features. I have gone w/likely POPS everywhere on Wed. Because even if no coastal low develops, that would probably be from the front stalling over the area. That scenario would result in stronger t-storms and warmer temps, but either way, we'd rain. I am not mentioning any winds or coastal effects yet, being so far out. I have gone way below temp guidance, trying to keep w/the theme of a rainy day and take the course of least regret. So highs near 70 degrees and rain. I have included a chance of imbedded t-storms. This is also the course of least regret, depending on where the front goes.
For Thu, likely POPs thru the morn, tapering to low-end chance as the day wears on. Whatever system is affecting the region should slowly pull out. Guidance temps are not happening unless a significant change in the hemispheric pattern occurs, so only upper 60s for highs!
If long range guidance is correct, we could be looking at a cool, to perhaps even significantly cooler than normal Sept, but we'll see on that!
Now, let's look at a couple of graphics concerning the upcoming week's weather. This map is for late Fri afternoon. Verbatim, the areas on this map are receiving the stronger t-storms. According to this model, it stays west of the state. It's going to be close, depending on when/where initiation occurs.