Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Dec 11 2022 08:17:48 AWUS01 KWNH 110817 FFGMPD MSZ000-LAZ000-TXZ000-111330- Mesoscale Precipitation Discussion 1154 NWS Weather Prediction Center College Park MD 316 AM EST Sun Dec 11 2022 Areas affected...Coastal Plain of Central to Southeast TX...Southern LA...Southwest MS... Concerning...Heavy rainfall...Flash flooding possible Valid 110815Z - 111330Z SUMMARY...Long broad line of thunderstorms likely to break into multiple clusters still capable of producing 2"/hr through to early morning. Localized totals of 2-4" may result in localized flash flooding. DISCUSSION...08z Surface analysis depicts the synoptic cold front has merged with the edge of the deeper Gulf mT air mass from SSF to UTS, with a developing linear convective outflow boundary along and south of it over to a weak meso-low near ESF in central LA.=20 South of the boundaries, shallow but still quiet unstable airmass with limited capping supports 1500-2000 J/kg of SBCAPE across the Coastal Plain of Texas, reducing to about 1000 J/kg across the southern bayous along and south of I-10 to about BTR where Tds drop from low 70s/upper 60s to mid and lower 60s.=20 Shortwave continues to press eastward across TX into LA with continued favorable diffluent flow across much of the eastern portion of the convective line, so better forcing eastward counteracts better thermodynamics west. Broad southerly Sfc to boundary layer flow will continue to intersect the outflow boundary orthogonally to maintain solid moisture flux convergence supporting stronger updrafts and efficient rainfall production.=20 Total Pwats remain about 1.75" and so will continue to support 2-2.5" rates, throughout the line.=20 The potential of flash flooding will be keyed on duration of the heavy rainfall. To the west, propagation southward will dominate as steering flow lessens as the wave exits eastward, this should allow for a few scattered cells/clusters to support 1-2 hours of heavy rainfall with isolated 3-4" totals. Further east into LA, the stronger steering flow remains fairly flat to the orientation of the boundary so training profiles are more probable with best potential south and west of the Gulf of Mexico boundary that aligns just west of the Mississippi River proper. Again, stripes of 2-4" are possible. Given the soil conditions have been dry over the past few weeks to month, flash flooding is considered possible and should be scattered to those locations of longest duration and aforementioned training conditions within the MPD area of concern through early morning Sunday. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6vtTxqrasmB6AVecRvaN7A7SUpSJJXp7G6HcgSk9LqvE_buXZ9JTjHV_y6E_TioJVJtZ= Z04UxqrL25Mr1oXp8Ypo5co$ for graphic product... ATTN...WFO...CRP...EWX...HGX...JAN...LCH...LIX... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 31899108 31889042 31488990 30838996 30319030=20 29999112 29989179 29949359 29459527 28499785=20 29279847 30089735 30799509 30959362 31109210=20 31679150=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) .