Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jun 20 2023 06:55:29 AWUS01 KWNH 200655 FFGMPD VAZ000-NCZ000-SCZ000-GAZ000-TNZ000-201253- Mesoscale Precipitation Discussion 0534 NWS Weather Prediction Center College Park MD 254 AM EDT Tue Jun 20 2023 Areas affected...Upstate SC...Western NC...Southwest VA Concerning...Heavy rainfall...Flash flooding possible Valid 200653Z - 201253Z SUMMARY...Slow-moving areas of very efficient shower activity, along with a few thunderstorms, will support locally heavy rainfall totals going through dawn. Some pockets of flash flooding cannot be ruled out. DISCUSSION...The latest GOES-E satellite imagery shows relatively warm-topped areas of convection advancing north-northeast up across areas of upstate SC, western NC and southwest VA in close proximity to the Blue Ridge. The activity is being aided by a combination of moist low-level convergence along a quasi-stationary front and with areas of orographic ascent/upslope flow into the east-facing slopes of the terrain. Radar shows some of the heaviest activity over the last hour situated east of Asheville and west of Rutherfordton, with additional heavy shower activity northwest of Hickory. The 00Z RAOB soundings from RNK and GSO were very moist and the GSO sounding had a rather high WBZ level (~12K feet). Instability is rather modest with MLCAPE values of around 500 J/kg, but with rather tall skinny CAPE profiles, and the depth of the warm cloud layer, the rainfall processes should be quite efficient. Deep layer ascent is also noted across the region around the eastern flank of the mid-level closed low/trough over the TN Valley. This forcing coupled with the aforementioned ororgraphics and frontal convergence should continue to foster slow-moving areas of heavy shower activity along with a few thunderstorms heading through the balance of the night and into the dawn time frame. Rainfall rates may reach as high as 2 inches/hour with the stronger convective cells and especially over western NC where there is relatively stronger instability. Areas farther north into southwest VA though will also likely see areas of persistent and locally heavy shower activity that will need to be monitored. The HRRR guidance over the last few hours has been advertising the potential for some pockets of 3 to 5 inch rainfall amounts going through 12Z (8AM EDT). Some of the earlier rainfall coupled with these additional totals early this morning may set the stage for there being some pockets of flash flooding. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!455pgGYSd9hKVBNufKvWXXTxoPnQQzBmsTF_xg8d-oNZqW3KNDmnOvKuC0CkpaMrAxCz= MokWkNOIuo5MW4AWJ3w2Bo8$ for graphic product... ATTN...WFO...GSP...MRX...RNK... ATTN...RFC...LMRFC...MARFC...OHRFC...SERFC...NWC... LAT...LON 37328017 37157988 36787989 35928082 35608117=20 35308152 34858220 34698262 34658298 34748316=20 34928319 35258294 35608261 36058216 36598154=20 37228079=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) .