Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jun 05 2024 17:46:10 AWUS01 KWNH 051746 FFGMPD PAZ000-MDZ000-VAZ000-DCZ000-WVZ000-052330- Mesoscale Precipitation Discussion 0401 NWS Weather Prediction Center College Park MD 145 PM EDT Wed Jun 05 2024 Areas affected...Northern WV...Southwest & Southern PA...Western & Central MD...Northern VA... Concerning...Heavy rainfall...Flash flooding possible Valid 051745Z - 052330Z SUMMARY...Potential for multiple rounds of intense rain rates 1.5-1.75"/hr. Proximity to complex terrain and urban centers pose greatest risk of high run-off and localized flash flooding potential through evening. DISCUSSION...GOES-E Visible imagery shows an old MCV/mid-level shortwave translating slowly northeastward through the Central Appalachians of W MD into W PA. Filtered insolation through the thinning cloud deck across the area of concern has seen an increase of temperatures in the low 80s over anomalously high Tds in the low 70s pooling in proximity to a broad warm frontal zone across the Mid-Atlantic. Deeper layer moisture through the Carolinas and through Virginia had brought overall Total PWats well above 1.75" in the lower terrain starting to near 2"; while areas of eastern slopes of the Appalachians are slowly rising from 1.5 to the 1.75" range or about 2 to 2.5 std dev from normal at this time of year. The weak wave is providing weak DPVA ascent but also is backing low level flow for increasingly confluent, subtly upslope for sufficient convergence to overcome the weak capping in the area.=20 Recent RADAR and satellite trends depict increasing convection especially near/east of the MCV across Garrett county as well as into the northern Piedmont of NoVA. These cells are working well enough to support 1.5-1.75"/hr rates and are initially slow given some terrain locking before deeper layer flow starts to move them off...so this is a short-term FF risk for localized 2"+ totals in 1-2hrs. However, coverage is likely to continue to expand in the southeast quadrant of the MCV and near the front with similar intense rates, these cells will be deep enough to start moving quick enough to reduce residency and limit overall totals, but support sub-hourly values up of 1-1.75" locally. This alone is not much of a threat for most location in the area of concern with exception of the higher/complex terrain and urban centers, initially. Further upstream shortwave energy and convergence bands in the clearer skies south of the MCV are likely to trigger another or perhaps even a third round of convection that have solid potential to repeat/cross paths as the line lift northeastward into southern PA and into central MD. Spots of 1.5-2.5" may occur to further expand the potential, though by no means will this be high in areal coverage but more widely scattered, randomly distributed through the MPD area (with higher concentration/potential in W PA, N WV, and W MD where FFGs are sizably lower due to terrain).=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4nAKr-H5JtrB4doTKCtBhxQwrA69iM9ta0y5lbimX9-MOcGH2qvkCbi7dPdGrBA0qAFG= Cj10EYkVNihc1fMd2ejBGHs$ for graphic product... ATTN...WFO...CTP...LWX...PBZ...RLX... ATTN...RFC...MARFC...OHRFC...NWC... LAT...LON 41377848 40967704 40127638 39507642 39007671=20 38637718 38387774 38127886 38368004 38578042=20 39298079 39748066 40338015 41137939=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) .