Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Apr 05 2025 19:16:35 AWUS01 KWNH 051916 FFGMPD TNZ000-KYZ000-INZ000-ALZ000-ILZ000-MSZ000-LAZ000-MOZ000-ARZ000-TXZ000-06011= 5- Mesoscale Precipitation Discussion 0129 NWS Weather Prediction Center College Park MD 315 PM EDT Sat Apr 05 2025 Areas affected...Lower MS Valley...Mid-South...Lower OH Valley Concerning...Heavy rainfall...Flash flooding likely Valid 051915Z - 060115Z SUMMARY...Widespread flash flooding with continued areas of training showers and thunderstorms will continue over the Lower MS Valley, Mid-South and Lower OH Valley going into the evening hours. High-end flash flooding with life-threatening and locally catastrophic impacts will continue to be a likelihood. DISCUSSION...Areas of extremely heavy rainfall will continue to unfold over the next several hours as an elongated axis of slow-moving and training showers and thunderstorms with high rainfall rates impact large areas of the Lower MS Valley, Mid-South and portions of the Lower OH Valley. The latest GOES-E IR satellite imagery shows a very large and impressively cold-topped convective canopy over the region, with dual-pol radar showing some of the strongest convection and heaviest rainfall rates associated with a QLCS stretching from southeast AR up across western TN. Rainfall rates with this feature are well into the 2 to 3 inch/hour range, and there has been at least some southwest/northeast oriented training of this band of severe convection. No major changes to the large scale pattern are noted as the convection continues to be driven by the gradual ejection of mid-level troughing/shortwave energy across the southern Plains with downstream interaction with a very moist and unstable 40 to 50+ kt southerly low-level jet focused along and out ahead of a strong frontal zone. Multiple waves of low pressure continue to transit the front which is yielding locally focused areas of low-level convergence and forcing within an area that is broadly divergent aloft. MLCAPE along and south of this front and also a nearby outflow boundary off to the east are on the order of 2000 to 3000 J/kg. Enhanced shear profiles remain in place with robust 0-3km bulk shear values of 50 to 60 kts which is favoring highly organized and severe-mode convection including supercell development. This very unstable/sheared environment coupled with very strong moisture transport will continue to favor extremely heavy rainfall rates in the 2 to 3 inch/hour range going through this evening as the overall convective axis gradually settles down to the south and east. The experimental WoFS and HRRR guidance support additional rainfall totals of as much as 3 to 6+ inches. Some of these additional rains will locally overlap with areas of the Mid-South and Lower OH Valley that are extremely sensitive and experiencing ongoing flooding. This includes parts of eastern AR, western TN and much of western KY. However, farther down to the south into northern LA, far southeast AR and northern MS, the antecedent conditions are notably drier with much higher FFG values. Therefore, the high-end threat for significant flash flooding and locally catastrophic impacts will continue to be over areas a bit farther north, inclusive of multiple major metropolitan areas that will see extreme rainfall potential. Areas farther south will be a bit more conditional with the threat, but will also still likely see flash flooding concerns with potential for significant impacts given the extreme rainfall rate potential. Additional localized Flash Flood Emergency level impacts overall remain a threat heading into the evening hours, and this situation will continue to be closely monitored. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_Fnn6fJQ5whc6VQMHy1b3neaQVWPSoDMkQCUmixC0VGJUJ3YCzw0D_ewIeYIVPJ6sOct= 7OspbwYmv0reS7mTHgr2mBM$ for graphic product... ATTN...WFO...HUN...ILN...IND...JAN...LMK...LSX...LZK...MEG... OHX...PAH...SGF...SHV... ATTN...RFC...ABRFC...LMRFC...NCRFC...OHRFC...SERFC...WGRFC... NWC... LAT...LON 38838648 38688465 37738437 36768538 35568736=20 34398894 33149048 32299154 31699282 31479380=20 31699485 32199497 33259453 34599348 36059201=20 37209047 38198882=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) .