Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue May 06 2025 22:34:06 AWUS01 KWNH 062233 FFGMPD NYZ000-NJZ000-PAZ000-070400- Mesoscale Precipitation Discussion 0236 NWS Weather Prediction Center College Park MD 633 PM EDT Tue May 06 2025 Areas affected...central NY to PA/NJ border Concerning...Heavy rainfall...Flash flooding possible Valid 062230Z - 070400Z SUMMARY...Isolated to widely scattered areas of flash flooding will remain possible across a broad section of Upstate NY down to the PA/NJ border through 04Z. Peak hourly rainfall up to 1.0-1.5 inches (especially early on) will be likely on an isolated basis. DISCUSSION...Radar imagery at 2230Z showed that a broken line of showers/thunderstorms extended from near Syracuse to the NY/PA/NJ border. A mesoscale axis of low level convergence to the west of Syracuse has resulted in a localized area of hourly rainfall in excess of 2 inches (north of Skaneateles) with surrounding locations in and around central NY to northeastern PA, in the 1-2 inch range (in 60 minutes). Water vapor imagery showed a well-defined, negatively tilted shortwave trough swinging toward the north over eastern PA, to the east of a mid to upper-level low center over northwestern PA. Flow ahead of this feature was strongly diffluent, aiding in lift within a weakly unstable airmass (500-1000 J/kg MUCAPE), though infrared cloud tops have been warming over the past hour. Through 04Z, the shortwave spoke is forecast to lift northward into central NY, sending the broken convective line toward the north and east into the Catskills and Hudson Valley. There is a low end threat for south to north training as the line advances east, though advection of drier and more stable air into the region from the southwest should lessen this the heavy rain/flash flood threat with time over eastern portions of NY. Over central NY, weaker deeper layer mean flow will continue to be supportive of slower movement of heavy rain cores with the ongoing axis west of Syracuse expected to advance off toward the northeast over the next couple of hours. Meanwhile additional heavy rain may move in from the south through 04Z with peak rainfall rates lowering into the 0.5 to 1.0 in/hr range as instability diminishes with the loss of daytime heating. An additional 1-2 inches of rain (locally a little above 2 inches over central NY) is expected on a localized basis which may linger the flash flood threat for another few hours over northern PA/NJ into NY. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_LvscJ0LH-UgyPdloWrQuY7y05MIaWEhDEJIGMQ_pYpb6LHRx8KqcVMcpWRivSBxpmce= GgvFt0X17xKLAfj9WEjC7ag$ for graphic product... ATTN...WFO...ALY...BGM...BTV...BUF...CTP...OKX...PHI... ATTN...RFC...MARFC...NERFC...NWC... LAT...LON 44567573 44147450 43527391 42747368 41367401=20 41047446 41057510 41407572 41577626 41877770=20 42487817 43287778 44027718 44467636=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .