Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 09 2024 09:18:25 AWUS01 KWNH 090918 FFGMPD NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-WVZ000-091515- Mesoscale Precipitation Discussion 0847 NWS Weather Prediction Center College Park MD 516 AM EDT Fri Aug 09 2024 Areas affected...Central Appalachians...Northern Mid-Atlantic...New York Concerning...Heavy rainfall...Flash flooding likely Valid 090915Z - 091515Z SUMMARY...Post-T.C. Debby continues to rapidly lift north through the Mid-Atlantic states, but continues to bring heavy rains along with significant and locally life-threatening flash flooding concerns. DISCUSSION...The early morning radar imagery, surface observations and satellite data shows the now Post-T.C./extratropical low center of Debby rapidly lifting north-northeast across far western VA, with the center of circulation notably elongated in a south to north fashion. Very heavy rains though continue to overspread portions of the central Appalachians and adjacent areas of the Blue Ridge and Piedmont of the Mid-Atlantic. This includes an area from from eastern WV and northwest VA up across western MD and much of central and western PA. Debby has merged with a frontal zone and strong warm air advection coupled with enhanced moisture transport across the Mid-Atlantic states continues to surge toward areas of the Northeast. A southerly low-level jet of 50 kts is in place around the east side of Debby's circulation and there continues to be the poleward surge of instability with the latest RAP analysis showing as much as 1000 to 1500 J/kg of MLCAPE over portions of the Piedmont and coastal plain of the Mid-Atlantic. Coinciding with this continues to be a belt of stronger low-level shear/helicity which is facilitating some organized/semi-linear bands of stronger convection with some mesocyclone activity. Some of these bands are showing up in radar across northern VA and separately across parts of south-central PA. Very high PWs, and the thermodynamic and kinematic environment, will continue to favor rainfall rates as high as 2 to 3 inches/hour with the stronger and more organized convective cells this morning as these bands lift off to the north. Meanwhile, strengthening frontogenesis and jet-enhanced forcing along with the moisture transport will favor widespread heavy rain overspreading areas from western and central PA through southern and central NY going through the morning hours. Additional rainfall totals along and ahead of the track of Post-T.C. Debby will reach as high as 3 to 6 inches by late this morning. The additional rains are expected to continue fostering numerous to widespread areas of flash flooding, with concerns for significant and life-threatening impacts. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9KBNwq7F4pKZBFwaomR_gpHxaXD48Z4kn9WrhIJD5Lx_HJHccYZxv8CKDPQlEG6Lx3kz= Db1XV4HdPruDa4WZt6XujWA$ for graphic product... ATTN...WFO...AKQ...ALY...BGM...BUF...CTP...LWX...OKX...PBZ... PHI... ATTN...RFC...MARFC...NERFC...OHRFC...NWC... LAT...LON 43637496 43327419 42707386 41967384 41187427=20 40067539 38407615 37807689 38007808 38557854=20 39247880 39767931 40817945 41477907 42207853=20 42937765 43597617=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) .