Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 25 2023 17:03:42 AWUS01 KWNH 251703 FFGMPD NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-252300- Mesoscale Precipitation Discussion 0578 NWS Weather Prediction Center College Park MD 102 PM EDT Sun Jun 25 2023 Areas affected...Eastern PA...Northeast MD...Far Northern DE...New Jersey...Southern NY... Concerning...Heavy rainfall...Flash flooding possible Valid 251700Z - 252300Z SUMMARY...Strong slow moving thunderstorms capable of 1.5-2"/hr with potential for cell mergers/collisions by mid-afternoon pose localized flash flooding potential near urban locales and areas with saturated soils over the past few days. DISCUSSION...GOES-E WV suite depicts the remaining small/compact closed low along the eastern portion of the Mason-Dixon line, still wobbling eastward. Along the eastern hemisphere, weak but sufficient DPVA and slightly cooler temps aloft have enhanced instability given ample surface heating this morning and lingering lower 70s dewpoints. Total moisture has scoured a bit but remains about 1.75" and temps climbing into the mid to upper 80s, SBCAPEs have risen to above 2000 J/kg. The profile supports warm cloud process and limited evaporation given the high humidity through 400mb in proximity soundings suggesting continued highly efficient rainfall production with 1.75-2"/hr rates becoming more likely with peak unstable environment over the next few hours.=20 Currently, sea-breeze along the Jersey shore as activated vigorous updrafts which is now expanding northward toward the NYC metro.=20=20 Given deeply stacked low, steering flow is limited and cells are likely to be more pulse in nature given limited bulk shear for organized structure. This will allow for highly localized heavy rainfall cores with 1.5-2" falling in sub-hourly to hourly time frames. Propagation along outflow boundaries and additional scattered development in the northeast quadrant of the upper-low will also have increasing potential for cell mergers or more likely outflow boundary collisions that may allow for broader up/downdrafts covering slightly larger localized areas.=20 Flash flooding is not likely to be an issue across the Pine Barrens (where cells are currently located), but locations along the I-95 corridor, especially near Philadelphia, Baltimore and Wilmington DE having seen recent heavy rainfall and flash flooding conditions remain most susceptible to enhanced runoff and flash flooding again today. However, expansion into the Poconos, southern Catskills and nearer NYC metro may have spots of 2-3" totals as well resulting in low end flash flooding or quick urban flooding concerns.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8LMk5aYUqu_NWJDple9gio9EdM7lFBPIfHl6Y7RdER_hhSpCKxjublwLrq_u2OMK2pYV= 9Xz6hjecZ_C438AISaeEu3Y$ for graphic product... ATTN...WFO...BGM...CTP...LWX...OKX...PHI... ATTN...RFC...MARFC...NERFC...NWC... LAT...LON 41967533 41937511 41557437 41147386 40597394=20 39557463 39437500 39467528 39447587 39217657=20 39587671 40387603 41077646 41527658 41927625=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .