WxWatcher007

Mesoscale Precipitation Discussion 0901 NWS Weather Prediction Center College Park MD 645 PM EDT Sun Aug 18 2024 Areas affected...Northeast Concerning...Heavy rainfall...Flash flooding likely Valid 182244Z - 190444Z Summary...Widespread flash flooding continues this evening across the Northeast, which will continue through the evening. Additional considerable to locally catastrophic impacts cannot be ruled out, especially over areas impacted by ongoing/earlier rainfall. Discussion...Widespread thunderstorms are underway across the Northeast ahead of a slow moving cold front analyzed across central Pennsylvania and western New York. Over the last several hours, rainfall rates upwards of 2"/hr combined with cell training and repeating have have led to numerous reports of impactful flash flooding across the region. RAP proximity soundings in the vicinity of these cells highlight a very favorable environment to drive intense rainfall rates upwards of 2"/hr, including a nearly saturated profile with 1.8-1.9" PWAT, 1000-1500 J/kg MLCAPE (in a "tall-skinny" profile), and warm cloud depths around 10,000 feet. While the mean-flow will support relatively quick cell motions of 25-30 kts, the parallel orientation to the synoptic forcing will favor training and repeating with slow eastward progression. As these storms continue over saturated soils and urban areas, the threat of significant flash flooding will continue through this evening, with 18Z HREF neighborhood probabilities showing a very high (70-80%) chance of 3 HR FFG exceedence through 3z. Additional considerable to locally catastrophic flash flooding impacts cannot be ruled out going forward, especially over areas hit hard from ongoing/previous rainfall, including western Connecticut which as seen 10+" of rainfall today.

Daily record seems like a lock. Truly extraordinary day.

Well now that the band is reaching my backyard it’s narrowing and drying up. You’re welcome, Connecticut.

You stop that talk right now Just need an Henri type pattern to collapse the steering flow or a stronger Debby that stayed offshore and pulled that PRE closer and there you have it.

Housatonic at Stevenson has gone from 2.68ft to just under 17ft (mid flood) in 3.5 hours.

Not sure what’s going to happen here, but I’m definitely watching what’s coming up from the Sound.

To the extent that FFEs are new, I think most of them have happened in recent memory.

Mesoscale Precipitation Discussion 0899 NWS Weather Prediction Center College Park MD 322 PM EDT Sun Aug 18 2024 Areas affected...Western Connecticut Concerning...Heavy rainfall...Flash flooding likely Valid 181922Z - 182252Z Summary...A localized cluster of cells continues to produce very impactful flash flooding over western Connecticut. Cells developing upstream will feed into this complex, which will continue the threat of significant flash flooding. Discussion...Radar continues to track a localized but very efficient cluster of cells which has persisted throughout the morning across western Connecticut. Nearly stationary cell motions and extreme rainfall rates exceeding 3"/hr at times has led to considerable to locally catastrophic impacts across the area, with radar estimates of 7-9" of rainfall noted as of writing. This focused area of extreme rainfall likely focused along a mesolow providing convergence for ascent and enhanced low-level inflow across the region. Upstream of the activity, SFC-850 ALPW and recent ASCAT surface winds also depict a well defined area of confluence embedded within a moist conveyor feeding into the convection. With continued heating, the first signs of cumulus streets and enhanced vertical development are noted upstream, which suggests the area is destabilizing. Thus, additional cells are expected to develop and feed into the area in the presence of the low level forcing.

Incredible stuff

Incredible. I’m at .63” here in central with barely any good echoes today.

I’m at .38 here and I wonder if this’ll just crawl east as that front advances.

Seeing over 5” now on radar estimates. This could get ugly.

Going to start working on my annual peak season forecast soon and I think a lot of folks are sleeping on just how high end the season has been so far. Maybe we have a 2017 like theme of “quality over quantity” taking hold.

Going to start working on my annual peak season forecast soon. Still thinking it’s extremely active once SAL climo falls some more.

SW CT getting smoked

Nobody around here is truly ready for anything close to Gloria, let alone a legit high end 2 or major. It’s not hyperbolic to say that it won’t need to be a cat 4 behemoth to be catastrophic in New England. Though I guarantee some would even meh that.

I’m guessing that whatever rebound occurs is modest at best. Given the current issues with dry air and its broad nature, I’m not sure there’s much time for it to surprise much on the intensity front.

Good to see you post. Best of luck up there and agree. Close graze seems most likely.

Now we watch for if there’s an additional landfall in Newfoundland. It’s likely going to be close.

https://www.portbermudawebcam.com/ We wish we were there but we don’t play Island Roulette.

I agree with the football spiking (which I think is more in jest here imo) But there are a lot of times where I think you can write off a system or a system’s impact here at range. I don’t think Ernesto was one of those until a few days ago for NE, but obviously it trended that way. Honestly though, I’m not even looking at a system before looking at the steering and development/intensification environment. You may not know exactly where a system is headed but there are times where you can see the writing on the wall 7-10 days or longer out. And there are times where the writing is wrong. I think folks here underestimate how often that happens. Just look at some of the eventual hits over the last 5 years and the conversation that precedes models locking on. I look more often than I like to admit.

The common thread through all the hurricanes this season has been prolonged periods of dry air ingestion. Pretty interesting considering all were in favorable environments otherwise when it happened. I thought the more classic AMO SST distribution would keep stability in check this season but so far that hasn’t been the case.

It’s miserable to read but that’s just how it goes.