Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Nov 30 2022 01:28:57 AWUS01 KWNH 300128 FFGMPD TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-300724- Mesoscale Precipitation Discussion 1137 NWS Weather Prediction Center College Park MD 826 PM EST Tue Nov 29 2022 Areas affected...northern Louisiana, northern/central Mississippi, southeastern Arkansas, southwestern Tennessee Concerning...Heavy rainfall...Flash flooding likely Valid 300124Z - 300724Z Summary...Continued re-initiation of convection and training of convective bands will cause issues with flash flooding through 07Z. Discussion...Scattered convection continues to gradually evolve in bands particularly across the Mid-South from near Shreveport/El Dorado east-northeastward to Memphis). A separate band of more cellular-oriented activity exists from near Vicksburg through the Jackson, MS Metro and on to near Columbus. These storms were on the northern edge of a very moist, deep boundary layer, with upper 60s to 70s F dewpoints supporting PW values around 1.6-1.8 inch.=20 Mean flow aloft was west-southwesterly at around 60 knots, which was enabling fast storm motions in individual convective cells.=20 The lack of strong low-level focus for storms was allowing for movement generally parallel to flow aloft, with training resulting in areas of 1-2 inch/hr rainfall rates especially near the Jackson Metro and in south-central Arkansas.=20 Objective analyses indicate the following factors supporting continued, upstream development of storms across Louisiana/Arkansas that will generally repeat across portions of the discussion area through the evening: 1) A plume of steep lapse rates aloft (nearing 8C/km) that will support robust updrafts amid moderate instability (2000 J/kg MLCAPE), 2) advancing mid-level shortwaves near the Ark-La-Tex and across central Kansas/Oklahoma that will provide lift to instigate strong updrafts within the lapse-rate plume, 3) convergent low-level flow (45+ knots at 850mb) that will help maintain low-level moisture, and eventually 4) a surface front over northwestern Arkansas that should focus convective development over the warm sector after 04Z or so initially across the Mississippi Delta and areas downstream. As these factors continue to evolve, scattered bands of convection will likely materialize - with the greatest concern over the MPD period existing across eastern Mississippi. This area will have the greatest chance of multiple rounds of heavier rainfall (hourly rates exceeding 1 inch/hr) on top of local areas that have already experienced 2-4 inches of rain. Additional areas of 2-4 inch rainfall totals (where training can become most pronounced) will lead to localized instances of flash flooding through 07Z. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8X_4RB1Smh9Pt2oJG3l3HfKRM0okJ47W4jlFDYL22E5lg6RRszu-KuYzEa_OM-WeDd9Y= _ELWMDlOvk0PZZLzV75WSB4$ for graphic product... ATTN...WFO...BMX...HUN...JAN...LZK...MEG...SHV... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 35468915 35028819 34208817 33488826 32808854=20 32269057 31929253 32179356 33089341 33939241=20 35059053=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) .