Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Mar 17 2025 02:25:03 AWUS01 KWNH 170225 FFGMPD NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-170824- Mesoscale Precipitation Discussion 0076 NWS Weather Prediction Center College Park MD 1024 PM EDT Sun Mar 16 2025 Areas affected...portions of the Mid-Atlantic Concerning...Heavy rainfall...Flash flooding possible Valid 170224Z - 170824Z Summary...Gradually deepening convection will migrate northeastward across the discussion area for the next several hours. Rates of 1-2 inches/hr are expected - highest across eastern Maryland into the DelMarVa. Isolated flash flooding is possible in this regime. Discussion...Several atmospheric factors are combining to result in increasing convective coverage and heavy rainfall across the discussion area, including: 1) convergence along a surface cold front extending from Charlottesville, VA to near Lancaster, PA, 2) strong low-level flow/warm advection, which was maintaining deeper convection near/east of Richmond, VA while also maintaining ~500 J/kg SBCAPE and 1-1.5 inch PW ahead of the front, 3) advancing mid/upper level vorticity (and ascent) from troughing centered over the Ohio Valley and central Appalachians. As these features continue to evolve slowly eastward over the next few hours, axes of heavier rainfall will continue to spread east/northeastward along and ahead of the aforementioned cold front. Spots of 1 inch/hr rain rates can be expected at times nearer the front, while heavier rainfall (including 2-2.5 inch/hr rain rates) could occur out ahead of the front as is currently being estimated near/east of Richmond, VA. FFGs across the discussion area are lowest across the DC-to-Philadelphia I-95 corridor (0.5-1.0 inch/hr) and these thresholds could be eclipsed on an isolated basis over the next 2-4 hours as the front makes its way eastward through the region. Heavier rain rates are expected east of I-95 toward the DelMarVa, although it appears that ground conditions/FFGs are a bit less sensitive in these areas, suggestive of more isolated flash flood potential. 2-3 inch rainfall totals are expected across the DelMarVa through 08Z tonight, with lighter totals expected elsewhere. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7Ce5av1YTI927ZG7X7fk5468shHGtUbotqmqvLvoedAIbDL3bVJ0yI5ANf6KErC3x2Ph= W1OxS8Q4GPh1UU3jnDhLs7E$ for graphic product... ATTN...WFO...AKQ...CTP...LWX...PHI...RNK... ATTN...RFC...MARFC...NWC... LAT...LON 40787539 40437427 39587434 38027549 37357691=20 37677889 38807814 40237663=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) .