####018000595#### PENA01 KWNH 151200 @UHPISF000CN MPDSUM@V2.0@0101700060@12150225@@0NMCGPHMPDp@!' `' ` @ & B7)p&PNAM02@@|NO MDs ARE CURRENTLY IN EFFECT @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 02/15/2025 1330Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @####018003249#### AWUS01 KWNH 151332 FFGMPD VAZ000-WVZ000-TNZ000-KYZ000-INZ000-MSZ000-MOZ000-ARZ000-151930- Mesoscale Precipitation Discussion 0038 NWS Weather Prediction Center College Park MD 830 AM EST Sat Feb 15 2025 Areas affected...Portions of the OH/TN Valleys and Mid-South Concerning...Heavy rainfall...Flash flooding likely Valid 151330Z - 151930Z SUMMARY...An expansive axis of heavy showers and thunderstorms with strong cell-training concerns will be promoting a widespread flash flood threat over the next several hours across portions of the OH/TN Valley region and Mid-South. DISCUSSION...The latest GOES-E IR satellite imagery shows an expansive areas of heavy shower and thunderstorm activity impacting areas of eastern AR up across central and western TN and much of central and southern KY. Light to moderate stratiform rains are noted north of here closer to the OH River and also into the central Appalachians. The convection that is organizing is associated with strong warm air advection which is being aided by a powerful southwest low-level jet of 50 to 60+ kts overrunning a strong frontal zone. This is driving very strong moisture transport which is showing up in an impressive fashion with the experimental CIRA-LVT (Layered Vapor Transport) imagery as it is depicting SFC/850 layer LVT magnitudes of 300+ kg/m/s. Meanwhile, a nose of MUCAPE values on the order of 500 to 1000 J/kg is now oriented up across central to northeast AR through western TN and western KY and this is helping to facilitate the broader axis of elevated convection. Over the next several hours, very strong warm air advection and moisture transport will continue to support organizing bands of convection that will be aligned with the deeper layer mean flow and thus will be conducive for a substantial level of cell-training. Increasing CAPE values with time along with strengthening shear profiles will support stronger convective elements that will yield increasingly heavy rainfall rates. Rainfall rates with the stronger storms may reach as high as 1 to 1.5 inches/hour at least going through midday, but with significant cell-training concerns, this may result in some rainfall amounts by early afternoon alone of 2 to 4 inches. The latest CAM guidance suggests areas of western/northern TN through southern KY will have the heaviest totals going through the 18Z to 20Z time frame, with somewhat lesser amounts farther north. Given the extremely sensitive/saturated soil conditions and already elevated streamflows for many locations, these rainfall totals over the next several hours are likely to begin resulting in widespread flash flooding. Additional MPDs will be issued this afternoon to update what should evolve into a high-impact and life-threatening flash flood event in time. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...JKL...LMK...LZK...MEG...MRX...OHX...PAH...RLX... ATTN...RFC...LMRFC...OHRFC...NWC... LAT...LON 38438386 37938214 36958191 36258289 35938480 35578763 34359122 34619187 35219176 36318988 37208813 38008597 ####018000789#### PENA01 KWNH 151200 @UHPISF000CN MPDSUM@V2.0@0101700060@12150225@@0NMCGPHMPDp@!' `' ` @ & B7)p&PNAM02@@[n'}}}}|}}}~~}~}}}}|}}||{||{||}}}~}~|{{{|{{{{@@n'@@n'@@GS0038 @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 02/15/2025 1332Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @