Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Sep 10 2024 13:37:02 AWUS01 KWNH 101336 FFGMPD LAZ000-TXZ000-101835- Mesoscale Precipitation Discussion 0987 NWS Weather Prediction Center College Park MD 936 AM EDT Tue Sep 10 2024 Areas affected...TX and southwestern LA coast Concerning...Heavy rainfall...Flash flooding possible Valid 101335Z - 101835Z Summary...Isolated flash flooding will be possible along TX coastal locations into far southwestern LA through 18Z. Rainfall rates of 1 to 2+ inches may allow for spotty 2-4" totals. Discussion...13Z radar imagery from KBRO showed the northwestern edge of higher reflectivity associated with the inner core of T.S. Francine located 80 miles southeast of South Padre Island, TX. There was a gap in rainfall northwest of Francine, between the inner core and a fairly persistent rain band impacting southern Kenedy into Willacy counties with MRMS-derived rainfall rates of 1 to 2+ in/hr. MRMS rainfall estimates are believed to be reliable given matching values of MRMS to local gauge data in/near Brownsville earlier between 09-12Z. A combination of 12Z soundings, GPS and SPC mesoanalysis data showed precipitable water values along the LA and TX coasts to be between 2.1 and 2.8 inches, and MLCAPE of up to 250 J/kg, except along the far southern TX coast where MLCAPE is estimated to be between 500-1000 J/kg. However, available instability was limited to coastal locations, falling off rapidly with inland extent. While Francine is currently moving slowly toward the north, an expected turn toward the northeast along with an increase in forward speed through 18Z is forecast by the 09Z NHC advisory. This motion will likely allow outer rainbands to move ashore the middle and upper TX coasts into far southwestern LA by early afternoon but instability should remain limited for coastal locations through 18Z, except for the upper TX coast where values of 500-1000 J/kg are forecast by recent RAP guidance. Low level convergence will allow for brief training potential along the entire TX coastline with rainfall rates of 1 to locally 2+ inches per hour and localized 2-4 inch totals. Flash flooding will be possible but should remain very isolated with some locations not seeing much if any rainfall through 18Z. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7Y5-kZLYwP3v9dMX9SHzUhpNllSG6OXHW3gIRAeoorBVYsTgqSsRQ47TWPn7NF9XNxYk= Md2lkReCmz3WN0B_8VziOXw$ for graphic product... ATTN...WFO...BRO...CRP...HGX...LCH... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 30119324 29879313 29599320 29459356 29199410=20 28619510 28209607 27689669 27179687 25889691=20 25899765 27069780 28219736 28879653 29709494=20 29979397=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) .