Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Apr 24 2025 09:16:22 AWUS01 KWNH 240914 FFGMPD LAZ000-241400- Mesoscale Precipitation Discussion 0167 NWS Weather Prediction Center College Park MD 514 AM EDT Thu Apr 24 2025 Areas affected...south-central LA Concerning...Heavy rainfall...Flash flooding possible Valid 240912Z - 241400Z Summary...Slow moving showers and thunderstorms will pose an isolated flash flood threat to portions of south-central LA over the next 3-5 hours. Slow cell movement with potential for 2 to 3+ in/hr rates will exist. Discussion...Local radar imagery from KPOE and neighboring sites showed a relatively small and largely warm-topped cluster of showers and thunderstorms over south-central LA at 09Z. Rainfall over the past few hours over LA has produced an outflow boundary which extended 20-30 miles south of and roughly parallel to I-10 from near Lake Charles to near Abbeville. Modest low level flow atop this boundary and low level speed convergence (seen via VAD wind plots at 925 mb and 850 mb) appeared to be contributing factors in the location of the cluster of heavy rain, factors not being modeled well by recent RAP runs. Enhanced divergence within the left-exit region of an upper level jet max over south-central TX into the western Gulf was also possibly aiding with lift across the region. While this cluster has been in place for several hours in some form, there are growing concerns for slowing of cell movement given recent radar trends. Continued overrunning of the rain-cooled boundary is expected to continue over the next 3-5 hours with components of slow moving/backbuilding/training allowing for localized heavy rainfall to continue across south-central LA. The environment is forecast to remain mostly unchanged over the next 2-3 hours and additional potential for 2 to 3+ in/hr rainfall rates will remain along with localized storm totals over 5 inches possible in a relatively short period of time. These high rainfall rates will be most concerning with any overlap of urban or other areas with poor drainage. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8xydkvqgJw6N_oHudG9lbPun5o1hx_Bigy_e9qfIKhxomhd60fAYnsXG48W7COMhWDuK= dEkuqQpXjdRhhYGoQzppQsA$ for graphic product... ATTN...WFO...JAN...LCH...LIX... ATTN...RFC...LMRFC...NWC... LAT...LON 30999214 30969128 30849089 30459061 29939068=20 29779159 29919251 30219280 30699269=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) .