####018002681#### AWUS01 KWNH 041629 FFGMPD VAZ000-NCZ000-WVZ000-TNZ000-042130- Mesoscale Precipitation Discussion 0219 NWS Weather Prediction Center College Park MD 1228 PM EDT Sat May 04 2024 Areas affected...Central Appalachian Mountains & Eastern Slopes... Concerning...Heavy rainfall...Flash flooding possible Valid 041630Z - 042130Z SUMMARY...Risk for scattered upslope slow-moving thunderstorms capable of 1-1.5"/hr rates/totals may result in localized flash flooding given complex/steep terrain. DISCUSSION...Current GOES-E trends denote an area of increasing clearing over the central Appliachians donwstream of approaching shortwave. Favorable surface (in mountain) to mid-level warm air advection is pressing the warm front north across the Cumberland plateau into NE KY while solid damming east of the range sharpens the FGEN across western NC in the eastern upslope regions. DPVA/height-falls along and just east of the spine of the terrain is likely to start backing low level flow more perpendicular to the orographics enhancing low level moisture flux convergence. Combined with broken insolation, temps are starting to increase and SBCAPE instability is also rising; and with Tds in the mid-60s values are going to reach near 1000-1500 J/kg. Due to terrain, lowest profile reduces total moisture values, but still reaches near 1.25+ and with strengthening flux to 15-20kts, moisture flux should allow for efficient low level rainfall production as cell mature. Steering flow remains weak to the northeast at 15-20kts but also parallel to the terrain suggesting training/repeating is possible. However, with near zero bulk shear, cells are more likely to be pulse in nature and liable to collapse in less than an hour resulting in sub-hourly rates/totals of 1-1.5". However, given strength of upslope, some cells may regenerate/back-build along favored peaks (or just east downslope), allowing for multiple up/downdraft cycles in similar proximity, in particular where frontal zone interaction enhances some additional FGEN forcing. As such localized totals of 1-2" are probable with perhaps on or two focused areas recieving 2-3" in 1-2hrs. As such, scattered incidents of flash flooding are possible within higher-slope/complex terrain. Gallina ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...GSP...MRX...RLX...RNK... ATTN...RFC...LMRFC...MARFC...OHRFC...SERFC...NWC... LAT...LON 38068088 37768046 37448031 36708063 36168094 35458185 35088292 35308347 35658359 36418307 37028255 37958140 ####018000887#### PENA01 KWNH 041200 @UHPISF000CN MPDSUM@V2.0@0101700060@12040524@@0NMCGPHMPD xP@!' `' ` @ & B7)p&PNAM02@@+k ~~|{{{l{{{{{|||}~~@@k @@k @@Cn}|zt{zzzy|{z{{{{{{zyzz{}|@@n@@n@@K0218 @@a0219 @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 05/04/2024 1628Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @