Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 27 2025 07:47:41 AWUS01 KWNH 270747 FFGMPD MAZ000-VTZ000-NYZ000-271345- Mesoscale Precipitation Discussion 0809 NWS Weather Prediction Center College Park MD 345 AM EDT Sun Jul 27 2025 Areas affected...Central and Eastern NY...Southwest VT...Northwest MA Concerning...Heavy rainfall...Flash flooding possible Valid 270745Z - 271345Z SUMMARY...Increasing coverage of showers and thunderstorms can be expected over the next few hours. Heavy rainfall rates and localized areas of cell-training may result in isolated pockets of flash flooding through the early morning hours. DISCUSSION...Upstream shortwave energy crossing the Lower Great Lakes region coupled with broad warm air advection and a very moist airmass will contribute to an increase in shower and thunderstorm activity over the next few hours. There is already broken coverage of relatively warm-topped convection advancing across central NY with alignment in close proximity to a warm front advancing east across the region. A westerly low-level jet of 30 to 40+ kts impinging on the area should further support a general expansion of convection off to the east, and especially with some increase in elevated CAPE, with MUCAPE values increasing to 500 to 1000 J/kg. Weak right-entrance region upper jet dynamics over the region coupled with the warm air advection/isentropic ascent regime should foster swaths of heavy shower and thunderstorm activity going through the early morning hours, with some localized areas of cell-training possible where the convection becomes oriented in bands with better alignment with the deeper layer steering flow. The PW environment is very moist with values of 2.0 to 2.25 inches across central NY. In fact, the 00Z/27 RAOB sounding at KBUF depicted a PW of 2.18 inches which is a record for the date. This deeply tropical airmass shows up very well in the latest CIRA-ALPW data, with enhanced moisture concentrations noted well up through the 500/300 mb layer. The setup is conducive for highly efficient rainfall processes that will promote locally very high rainfall rates that could reach or briefly exceed 2 inches/hour. In fact, the latest GOES-E IR satellite imagery and MRMS-data suggest some ongoing warm rain processes with the current activity. Areas of central and eastern NY should see the heaviest concentrations of rainfall going through the early morning hours, with perhaps some downstream areas of southwest VT and northwest MA potentially getting into some heavy rainfall after dawn. Some localized swaths of 3 to 4+ inch rainfall totals will be possible, and there is at least some potential for this to drive isolated pockets of flash flooding. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5Rq610gzgyIZ_mb7WBWBIa4-QmvPdTNmfZkWusZzEMrn1VnVSEN3uNpYVNRAMzcJV8e7= ZmOTL2QXvsUKSEQr6YYTq4s$ for graphic product... ATTN...WFO...ALY...BGM...BOX...BTV...BUF... ATTN...RFC...RHA...TAR...NWC... LAT...LON 44077534 43797406 43247296 42487295 42207367=20 42307465 42627546 43137631 43647646 44007606=20 =20=20=20=20=20=20=20=20=20=20=20=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .