Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 26 2024 04:03:17 AWUS01 KWNH 260403 FFGMPD ALZ000-MSZ000-LAZ000-261000- Mesoscale Precipitation Discussion 0114 NWS Weather Prediction Center College Park MD 1201 AM EDT Tue Mar 26 2024 Areas affected...Portions of Central/Eastern LA through Central/Southern MS and Western AL Concerning...Heavy rainfall...Flash flooding possible Valid 260400Z - 261000Z SUMMARY...Additional isolated to widely scattered instances of flash flooding will be possible heading through the overnight hours from a well-organized line of showers and thunderstorms with very heavy rainfall rates. DISCUSSION...The latest radar imagery shows a broken QLCS oriented in a southwest to northeast fashion from portions of central LA through central MS. The northern portion of this convective line, generally near and northeast of Jackson, MS, has been tending to bow a bit more progressively off to the east which has tended to mitigate the rainfall totals somewhat despite the very organized structure of the convection. However, the portion of the line that involves areas of central LA into at least southwest MS has been slower moving and over the last 1 to 2 hours has begun to exhibit some short-term training character. This is occurring as the convection becomes aligned more parallel to the deeper layer southwest flow out ahead of an upper-level trough moving into the MS Valley. There is a fair amount of instability lurking out ahead of the southwest portion of the QLCS across eastern LA and southwest MS where MLCAPE values are still on the order of 1000 to 1500+ J/kg. This coupled with a strong and convergent low-level jet of 50 to 60 kts and 50+ kts of effective bulk shear is likely to support QLCS sustenance over the next several hours that will be capable of producing very heavy rainfall rates. The PWs have risen to locally 1.5 to 1.75 inches, and this coupled with the favorable thermodynamic environment and strong shear-enhanced updrafts should help support rainfall rates that occasionally reach or exceed 2"/hour. The latest 00Z HREF guidance appears to be under doing the convective organization of the strong cluster of cells south of Natchez, MS and north of New Roads, LA. This activity in particular is rather slow-moving, but is exhibiting some very cold overshooting top activity within the last hour, and is likely producing rainfall rates of 2.0 to 2.5"/hour. The larger scale convective threat should overall continue to advance downstream across central and southern MS and will eventually get into areas of western AL. The southwest flank of the line that still impacts portions of central/eastern LA and southwest MS will generally have the greater cell-training potential. Some rainfall totals of 2 to 4 inches with isolated heavier amounts will be possible where this occurs. Additional isolated to widely scattered instances of flash flooding will be possible as a result, and this will include the more sensitive urban locations where runoff will be more pronounced. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5CAFZXioAMaeM8kc6iS0WlupezhKzb5OI2ajb6KLceiQAOJQ9Vgs-vV7I_ZM2suYbfN3= LIv_FQeu4xls7-vkSJAnz6A$ for graphic product... ATTN...WFO...BMX...JAN...LIX...MEG...MOB... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 33798801 33508751 32608764 31368871 30588956=20 30379000 30249075 30409141 30739167 31049168=20 31549131 33168966 33678888=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) .