Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Dec 14 2022 18:55:20 AWUS01 KWNH 141855 FFGMPD FLZ000-ALZ000-MSZ000-LAZ000-150053- Mesoscale Precipitation Discussion 1163 NWS Weather Prediction Center College Park MD 154 PM EST Wed Dec 14 2022 Areas affected...southeastern Louisiana, southern Mississippi, southwestern Alabama Concerning...Heavy rainfall...Flash flooding likely Valid 141853Z - 150053Z Summary...Deep convection across Louisiana/Mississippi has become substantially more progressive over the past hour or so. Flash flooding will remain possible - especially where convective training can materialize and as storms move across areas that have already received heavy rainfall this morning. Discussion...Convection has trended much more progressive in the past hour or so in response to 1) approaching mid-level forcing from a shortwave trough over north Texas and 2) a deepening low along an advancing front in southeastern Louisiana, which has enhanced low-level convergence over the open warm sector and led to a marked increase in convective coverage. The advancing front and upscale growth of storms has led to faster forward propagation in southwestern Mississippi compared to earlier this morning, with 1-1.5 inch/hr rainfall rates occurring over areas that have already received 3-5 inch rainfall totals from Wilkinson to Copiah Counties. The short term flash flood threat in this area should persist for another 1-2 hours, and locally significant flooding remains possible. Ahead of the aforementioned convective band in Mississippi, numerous cellular storms have evolved in a very unstable, moist warm sector. The cellular and progressive nature of the activity has resulted in more of an isolated flash flood threat so far, although any cell mergers and/or training could enhance rainfall rates enough to exceed the ~2 inch/hr FFG thresholds currently in place across eastern Mississippi north of U.S. 98. Additionally, a few of these areas (from Brookhaven to Meridian) have experienced 1-4 inch rainfall totals over the past 6 hours.=20 Ground conditions also become more sensitive (lower FFGs) with northern extent (especially north of I-20). The flash flood threat should steadily increase in these areas and western Alabama - especially where training of storms can materialize and enhance local rainfall rates above 1 inch/hr. The flash flood risk should remain fairly isolated along and south of the I-10/I-12 corridor in Louisiana/southern Mississippi as cells mature over ground conditions that can handle more rain. The risk here will be moreso tied to rainfall occurring atop urbanized/low-lying areas (where a quick 1-1.5 inches of rainfall could cause issues.) Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_bhPUqUQA5gao2qOAlzGuYugmxmdA2Vi-N019dn1tT7u83Wx8NXouDyvmIFkE0-CjpbZ= FOR2-cjedtQ08FtaS0sPsUI$ for graphic product... ATTN...WFO...BMX...JAN...LCH...LIX...MOB... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 33838687 33588638 33148632 32308630 31168656=20 30488750 29878860 29098925 28889031 29099197=20 29499241 30259200 31329116 32499036 33098961=20 33728801=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) .