Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 28 2023 13:51:54 AWUS01 KWNH 281351 FFGMPD FLZ000-GAZ000-ALZ000-MSZ000-LAZ000-281950- Mesoscale Precipitation Discussion 0144 NWS Weather Prediction Center College Park MD 950 AM EDT Tue Mar 28 2023 Areas affected...Central Gulf Coast Concerning...Heavy rainfall...Flash flooding possible Valid 281350Z - 281950Z SUMMARY...Heavy showers and thunderstorms, with some possible cell-training, may result in a localized threat of flash flooding over the next 3 to 6 hours. DISCUSSION...The latest satellite imagery shows organizing and cooling convective tops down across areas of eastern LA and especially southern MS as a low-amplitude shortwave trough and surface wave of low pressure advances east-northeast across the central Gulf Coast region. This energy is interacting with a quasi-stationary front draped across the region and the latest RAP analysis shows a formidable instability gradient along the front, with the greatest instability noted over southern MS where MLCAPE values are locally over 2000 J/kg. Relatively strong moisture convergence is noted along the front and the radar imagery shows multiple clusters of convection developing along the front a bit farther north and independent of activity that is also seen closer to coastal areas of southern MS. Some additional uptick in convective organization is expected over the next few hours, and especially for downstream areas of the central Gulf Coast including southern AL and gradually portions of the FL Panhandle. The rainfall rates are likely to reach as high as 2 inches/hour with the stronger and more organized convective cores. The early morning HRRR guidance definitely appears underdone with the short-term QPF amounts given the current convective trends, and the overnight HREF guidance similarly has struggled with the timing, placement, and organization of the ongoing activity. Portions of southern MS and southern AL have seen heavy rainfall over the last 1 to 2 days, and the additional rainfall over the next several hours may impact these areas to the extent of fostering more efficient runoff concerns. Generally, the current thinking is that some additional 2 to 4 inch rainfall amounts may materialize, with isolated heavier totals considering that the convection is tending to align itself with the deeper layer west-southwest flow, and thus suggestive of some cell-training. Given the setup, at least a localized threat of flash flooding will exist, and especially for the more prone urban corridors. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6_fnYijbzOSmzTUAo1Mw9dKioHhUqnfK6Ya4sQls433EtP5lgdLT-I-B5SWH9ei_iIt0= nVmV32IbinKoZCYsMjl11Pc$ for graphic product... ATTN...WFO...BMX...JAN...LIX...MOB...TAE... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 31978611 31748524 31308495 30818512 30478593=20 30348747 30318829 30338959 30779080 31249079=20 31718951 31938809=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) .