Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 30 2024 15:14:16 AWUS01 KWNH 301514 FFGMPD LAZ000-302013- Mesoscale Precipitation Discussion 0950 NWS Weather Prediction Center College Park MD 1113 AM EDT Fri Aug 30 2024 Areas affected...Eastern LA Concerning...Heavy rainfall...Flash flooding possible Valid 301513Z - 302013Z SUMMARY...A short-term threat for training showers and thunderstorms will continue along with the potential urban flash flooding. This will include the New Orleans metropolitan area and adjacent suburbs. DISCUSSION...The latest radar imagery in conjunction with GOES-E IR satellite imagery shows a loosely organized band of training showers and thunderstorms impacting areas of eastern LA in a general south-southeast to north-northwest fashion. This includes portions of the New Orleans metropolitan area, along with areas adjacent to Lake Pontchartrain. The convection is embedded within a very moist, unstable and confluent low-level flow pattern across the northwest Gulf Coast region which is being influenced by an area of disturbed weather near the Upper TX coast. There is a rather well-defined instability gradient aligned with the convection over eastern LA with MLCAPE values locally as high as 1500+ J/kg. A corridor of relatively focused moisture convergence is noted here as well, and the combination of these ingredients along with rather divergent flow aloft is likely to maintain at least some loose organization of the ongoing convection going through the mid-afternoon hours. PWs are deeply tropical across the region with values of 2.25+ inches in place. This coupled with the level of instability, including the profile from the 12Z LIX RAOB sounding suggests extremely efficient rainfall with very high rainfall rate potential. The latest hires CAM guidance is not handling the ongoing activity well at all, with multiple HREF members mishandling the placement of the ongoing convective axis and the overall intensity of it. Based on the level of very cold convective tops, and radar trends which certainly suggests concerns for a persistence of training convective cells, there may be some additional rainfall totals going through mid-afternoon that reach 3 to 5 inches. This will be supported by some rainfall rates that reach 2 to 3 inches/hour with the stronger cells. Urban flash flooding, especially for the New Orleans metropolitan area and the adjacent suburbs, will continue to be the dominant concern over the next several hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8pbkQYLVIl1d1IMOq4Yha2FOb8ZRLAEZ__RQSfLG4OeOiVrCTi7LQSi14htieKW9n44y= QbtAyUpTe7N7S7-Hx9flAA0$ for graphic product... ATTN...WFO...LIX... ATTN...RFC...LMRFC...NWC... LAT...LON 30879030 30068948 29138932 29139002 29759032=20 30119061 30689099=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) .