Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Apr 04 2025 11:04:32 AWUS01 KWNH 041104 FFGMPD VAZ000-WVZ000-OHZ000-TNZ000-KYZ000-INZ000-ILZ000-MOZ000-041530- Mesoscale Precipitation Discussion 0117 NWS Weather Prediction Center College Park MD 703 AM EDT Fri Apr 04 2025 Areas affected...Portions of the Ohio Valley and Central Appalachians Concerning...Heavy rainfall...Flash flooding likely Valid 041103Z - 041530Z SUMMARY...Widespread areas of areal flooding and flash flooding will continue through the early to mid-morning hours with locally considerable impacts as additional rounds of heavy showers and thunderstorms arrive. Some improvement expected by late morning. DISCUSSION...The early-morning GOES-E IR satellite imagery along with dual-pol radar shows an extensive axis of cold-topped convection associated with heavy showers and thunderstorms impacting large areas of Kentucky with an eastward extension of this down into areas of western and southern West Virginia. The convection continues to be supported by a south-southwest low-level jet of 30 to 40+ kts with a nose of modest instability characterized by MUCAPE values of as much as 500 to 1000 J/kg. A somewhat complicated frontal structure is in place as well with a surface frontal boundary situated across middle Tennessee and into the central Appalachians with an inverted trough back to the northwest of this over Kentucky that is more reflective of a rather strong 850/925 mb front. The convergence along this feature coupled with strong warm air advection and moisture transport over the surface boundary is contributing to the extensive axis of convection that still currently remains in place. PWs across the region are generally on the order of 1.5 to 1.7 inches which is running about 2 standard deviations above normal for this time of the year, and this continues to favor heavy rainfall rates with aid from the low-level jet. Some rainfall rates with the current activity continue to be upwards of 1 to 2 inches/hour, with some of the heaviest rates seen over central and southern Kentucky and coinciding with the colder convective tops. A series of very low-amplitude vort impulses embedded within the stronger deeper layer west-southwest mid-level flow will tend to support some sustenance of the convection at least for the next 2 to 3 hours, but the 06Z HREF guidance generally suggests an overall weakening trend of the convection by later this morning as this energy advances downstream and away from the region. Additional rainfall amounts of 1 to 3 inches can be expected prior to this. Regardless, extremely sensitive soil conditions along with high streamflows will support generally any additional rainfall going right into runoff, with areal flooding and flash flooding likely to continue this morning which will include locally considerable impacts on the ground. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5Fznc_x1McqQxNPWHnplxKufBF9opAbQWow7JJhAz7Q7psbzXESMyqNSHDL4uqVKT0Gy= FhujT9pj9qC5If6c5iWgQWo$ for graphic product... ATTN...WFO...ILN...JKL...LMK...MEG...MRX...OHX...PAH...RLX... RNK... ATTN...RFC...LMRFC...OHRFC...NWC... LAT...LON 39148251 38998040 38028020 37068290 36598543=20 36118826 36268923 36888916 37498816 38018666=20 38658487=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) .