Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jul 25 2023 17:47:49 AWUS01 KWNH 251747 FFGMPD MAZ000-NHZ000-RIZ000-VTZ000-CTZ000-NYZ000-252300- Mesoscale Precipitation Discussion 0792 NWS Weather Prediction Center College Park MD 147 PM EDT Tue Jul 25 2023 Areas affected...Southeast NY...Southern New England... Concerning...Heavy rainfall...Flash flooding possible Valid 251745Z - 252300Z SUMMARY...Slow moving thunderstorms ahead of main shortwave likely to be slow moving thunderstorms resulting in widely scattered possible flash flooding. Additional upstream cells could further exacerbate flooding conditions by repeating across already saturated grounds. DISCUSSION...GOES-E WV suite depicts base of large scale trough marked by compact shortwave starting to press into NE PA.=20 Downstream, low level conditions were a bit drier aloft, but have started to see a stead increase in southwesterly low to mid-level flow increasing deep layer moisture. Strong surface heating has increased temperatures into the low 80s, with mid to upper 60s Tds providing buoyant environment for scattered thunderstorms.=20 Regional RADAR mosaic denote scattered development across SE NY across S MA, this generally aligns with a low level confluence/deformation zone extending from the shortwave toward the northeast. It is proximity to the boundary with approaching upstream height-falls that have resulted in stronger 850mb inflow reducing forward propagation vectors, and so initial cells have produced 1-1.5"/hr and have been and are likely to continue to be fairly stationary for the next hour or so, before exhausting local instability. Spots of 2-3" are possible in these widely scattered cells. As the shortwave approaches, stronger south-southwesterly flow should increase and along with deeper moisture profile support stronger flux convergence along the boundary. Additional cells are probable to develop/track through this axis with a potential of short-term training/repeating. Additional 2-3" totals (rates up to 1.5-2"/hr) will be tracking through areas of high soil saturation with AHPS 7 to 14 day anomalies above 200%. As such,=20 flash flooding is considered possible for ongoing convection as well as further into the evening hours. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!69rIL_KUgGlr5GUMDDZHtLu4abDsdOxrWrXuzgOJTZFR6o8yYp3bxMuHpX8aL9v0cM-T= mqFs7g9EnDEWDWdfx8bLRY0$ for graphic product... ATTN...WFO...ALY...BOX...GYX...OKX... ATTN...RFC...NERFC...NWC... LAT...LON 43157229 43037074 41687100 41367179 41267347=20 41797431 42447430 42937363=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .