Disc: Tis the season of up and down temperatures and frequent frontal passages. Welcome to fall in Southern New England! The biggest concern through this forecast period is moisture from Hurricane Delta early next week, as well as a fairly potent cold front right on its heels.
Currently: Yesterday's cold front is offshore and cleared of the entire area. Sprawling high pressure over the Great Lakes has brought chilly air into the area today.
Tonight: Temperatures will fall well tonight, with dry air and good radiational cooling conditions. Because of this, I have elected to go a couple degrees below temp guidance. As is typical on a radiative night, there should be a good deal of variation. Most lows shud be in the upper 30s to mid 40s. Some places on the immediate SE coast may be a bit warmer.
Tomorrow: With high pressure moving right overhead, temperatures should return to near normal levels, after a chilly start. Temp guidance is in the mid to upper 60s and on a day like tomorrow, there really isn't any reason to quibble w/what guidance is showing, so that will be the fcst.
Tomorrow night/Sat: As high pressure pulls offshore, temperatures on Saturday will be quite a bit above normal. However, humidity lvls will still be low. This indicates to me that Fri night could still be quite chilly and the usual radiative locns wl still radiate well. Gdnc high temps are in the mid 70s and this looks fine.
Long Term: Instead of doing a "day by day" long term, this time I am going to group it by event and threats, because it just seems to work better for this package.
First, The remnants of Delta... Sunday now looks to stay dry, as all guidance does not show rain reaching the state until after midnight. So we'll call it dry with increasing cloudiness. For now, will stick close to guidance temps, which shows highs around 70. But if the sys speeds up at all, then clouds and onshore flow get here earlier, and my fcst could be a couple degrees too warm.
Latest guidance has trended a bit further north with the precipitation. However, there is a 1030+ high to the north and what the GFS is showing is very plausible. Because of the high to the north, pcpn arrives in SW CT Mon morn, but takes until Tues morn (when added forcing from the cold front/ULL is present) to get to NE CT. NW Hills would get wet by midday Mon, with SE CT sometime around dinner time. It is an odd progression, but it makes sense, as the high to the north bleeds down cool, dry air. Also, as you might expect, precipitation amounts vary greatly, with up to 2 inches possible in SW CT to less than a half inch up north.
So, for Monday's forecast: Rain probably south of I 84 trending towards drier the further north you go. I went below temp guidance for Mon, as even if it doesn't rain in places, it will be cloudy with an onshore flow. Xpct highs in the mid to upper 50s.
I have showers and storms for the entire state on Tuesday, as the cold front/ULL get absorbed into the remnants of Delta. Because of this, temp guidance looks too warm to me once again. In addition to the showers, there could be a localized strong strom/small hail producer with the ULL approaching and steep lapse rates. Xpct highs in the mid 60s.
For Wed, the upper level low is still overhead, but there should be more sun, so I'll lower to scattered coverage of storms. i went warmer than guidance, as I think guidance is too cloudy Wed and the upper lvls are quite warm. Xpct highs in the low 70s.
For Thu, the upper level low is still spinning nearby, but beginning to fill in and weaken. So then I reduce coverage even more, to isolated. Again I went warmer than temp guidance, with more sun expected than what guidance coveys, and xpctd highs in the low 70s.
There could be another shot of scattered t-storms as a strong cold front finally clears the region on Friday.
The long range looks pretty typical for this time of year, with widely varying temperatures and strong frontal passages. It should be noted that there is a strong thermal gradient nearby, so models might have some difficulty w/temps. A small deviation could result in temps being much warmer or cooler.
I will post two graphics today- the first showing Delta's moisture during the day Monday, and the second later Tuesday, showing added influence from the upper level low.
On this first image, note how the moisture has begun to reach SW CT, but the departing high over Nova Scotia is keeping most of the rest of the state dry.
Currently: Yesterday's cold front is offshore and cleared of the entire area. Sprawling high pressure over the Great Lakes has brought chilly air into the area today.
Tonight: Temperatures will fall well tonight, with dry air and good radiational cooling conditions. Because of this, I have elected to go a couple degrees below temp guidance. As is typical on a radiative night, there should be a good deal of variation. Most lows shud be in the upper 30s to mid 40s. Some places on the immediate SE coast may be a bit warmer.
Tomorrow: With high pressure moving right overhead, temperatures should return to near normal levels, after a chilly start. Temp guidance is in the mid to upper 60s and on a day like tomorrow, there really isn't any reason to quibble w/what guidance is showing, so that will be the fcst.
Tomorrow night/Sat: As high pressure pulls offshore, temperatures on Saturday will be quite a bit above normal. However, humidity lvls will still be low. This indicates to me that Fri night could still be quite chilly and the usual radiative locns wl still radiate well. Gdnc high temps are in the mid 70s and this looks fine.
Long Term: Instead of doing a "day by day" long term, this time I am going to group it by event and threats, because it just seems to work better for this package.
First, The remnants of Delta... Sunday now looks to stay dry, as all guidance does not show rain reaching the state until after midnight. So we'll call it dry with increasing cloudiness. For now, will stick close to guidance temps, which shows highs around 70. But if the sys speeds up at all, then clouds and onshore flow get here earlier, and my fcst could be a couple degrees too warm.
Latest guidance has trended a bit further north with the precipitation. However, there is a 1030+ high to the north and what the GFS is showing is very plausible. Because of the high to the north, pcpn arrives in SW CT Mon morn, but takes until Tues morn (when added forcing from the cold front/ULL is present) to get to NE CT. NW Hills would get wet by midday Mon, with SE CT sometime around dinner time. It is an odd progression, but it makes sense, as the high to the north bleeds down cool, dry air. Also, as you might expect, precipitation amounts vary greatly, with up to 2 inches possible in SW CT to less than a half inch up north.
So, for Monday's forecast: Rain probably south of I 84 trending towards drier the further north you go. I went below temp guidance for Mon, as even if it doesn't rain in places, it will be cloudy with an onshore flow. Xpct highs in the mid to upper 50s.
I have showers and storms for the entire state on Tuesday, as the cold front/ULL get absorbed into the remnants of Delta. Because of this, temp guidance looks too warm to me once again. In addition to the showers, there could be a localized strong strom/small hail producer with the ULL approaching and steep lapse rates. Xpct highs in the mid 60s.
For Wed, the upper level low is still overhead, but there should be more sun, so I'll lower to scattered coverage of storms. i went warmer than guidance, as I think guidance is too cloudy Wed and the upper lvls are quite warm. Xpct highs in the low 70s.
For Thu, the upper level low is still spinning nearby, but beginning to fill in and weaken. So then I reduce coverage even more, to isolated. Again I went warmer than temp guidance, with more sun expected than what guidance coveys, and xpctd highs in the low 70s.
There could be another shot of scattered t-storms as a strong cold front finally clears the region on Friday.
The long range looks pretty typical for this time of year, with widely varying temperatures and strong frontal passages. It should be noted that there is a strong thermal gradient nearby, so models might have some difficulty w/temps. A small deviation could result in temps being much warmer or cooler.
I will post two graphics today- the first showing Delta's moisture during the day Monday, and the second later Tuesday, showing added influence from the upper level low.
On this first image, note how the moisture has begun to reach SW CT, but the departing high over Nova Scotia is keeping most of the rest of the state dry.
Lastly, this is the moisture associated with the upper level low. Note how this moisture overspreads the entire area quite easily.
That's all for now! See you next week! stay safe!
