Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Apr 07 2023 07:12:39 AWUS01 KWNH 070712 FFGMPD MSZ000-LAZ000-071310- Mesoscale Precipitation Discussion 0168 NWS Weather Prediction Center College Park MD 310 AM EDT Fri Apr 07 2023 Areas affected...Southwest to Central LA...Far Southwest MS Concerning...Heavy rainfall...Flash flooding likely Valid 070710Z - 071310Z SUMMARY...Slow-moving and locally repeating areas of showers and thunderstorms should continue to favor areas of flash flooding going into the early morning hours. DISCUSSION...The latest radar imagery shows a persistent axis of heavy showers and thunderstorms impacting areas of southwest to central LA and also into portions of far southwest MS. The convection continues to focus along and north of a quasi-stationary front draped from the northwest Gulf of Mexico through southern LA and southern MS. Warm and very moist deep layer southwest flow overrunning the front is driving isentropic ascent, and this coupled with a southwest/northeast axis of enhanced 925/700 mb frontogenetical forcing and elevated instability continues to favor an environment conducive for regenerating areas of heavy showers and thunderstorms. MUCAPE values are locally 1000 to 1500 J/kg across southwest to south-central LA and this coupled with PWs of 1.5 to 1.75 inches is helping to favor rainfall rates reaching as high as 2 inches/hour with the stronger convective cells. The rates have come down a bit compared to the mid to late-evening time frame when extremely high rates and convective organization was seen, but the rates remain rather high locally, and the cell motions are quite slow. As a result, there continues to be concerns for excessive rainfall totals promoting additional areas of flash flooding. The 00Z HREF guidance has largely struggled overnight with its handling of the placement of the more organized convection and more recently the persistence of it. Recent HRRR runs also appear to be locally underdone with its QPF given the radar and satellite trends. Expect the ongoing convective rains to tend to continue going through the early morning hours, with broken coverage of showers and thunderstorms that will continue to locally repeat over the same area and impact locations that have already reported several inches of rain, and especially southwest LA where some rainfall totals have approached and locally exceeded 10 inches since early evening. Locally an additional 2 to 4 inches of rain will be possible going through the early morning hours, and this will likely favor additional areas of flash flooding or enhanced runoff given the wet/saturated soil conditions. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!873KqjMJIWIlPM5ICPBDktIdJkuTvqjQefnrCIKlbV556EkzSTR0ffLS_jXghNaarg2L= Kb7T8Mgzy1sc0DKx8XfvAmU$ for graphic product... ATTN...WFO...JAN...LCH...LIX...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 31759118 31659078 31199068 30429109 29879167=20 29579240 29689335 30029366 30349357 30959262=20 31509189=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) .