Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun May 14 2023 08:27:02 AWUS01 KWNH 140826 FFGMPD TXZ000-141425- Mesoscale Precipitation Discussion 0292 NWS Weather Prediction Center College Park MD 426 AM EDT Sun May 14 2023 Areas affected...Southeast TX Concerning...Heavy rainfall...Flash flooding likely Valid 140825Z - 141425Z SUMMARY...An increase in the coverage of showers and thunderstorms is expected this morning. Very heavy rainfall rates and localized cell-training coupled with relatively moist soil conditions will favor a likelihood of seeing areas of flash flooding. DISCUSSION...Surface observations over the western Gulf of Mexico coupled with GOES-16 proxy visible satellite imagery and the KCRP/KHGX dual-pol radars suggest that an area of low pressure has formed offshore of the middle TX coast. There has been an uptick in shower and thunderstorm activity over the last couple of hours around this low center, and there are also a few broken small-scale clusters of convection over the southeast TX coastal plain to the west of the Houston metropolitan area. The activity that is inland is generally focusing along an instability gradient that is co-located with a weak inverted surface trough and corresponding axis of somewhat stronger low-level convergence. Over the next several hours heading through mid-morning, an additional increase in shower and thunderstorm activity is expected as this energy offshore with the low center lifts northwestward. Increasingly stronger moisture convergence near the middle TX coast in particular may favor convection becoming locally concentrated and focused. PWs of 1.8 to 2.0 are in place which coupled with as much as 1000 to 1500 J/kg of MLCAPE and some modest low to mid-level shear should favor some organized convective cells with very heavy rainfall rates. These rates are expected to approach or locally exceed 2.5 inches/hour. The latest CIRA-ALPW data plots show a very moist vertical column and thus the environment is likely conducive for some very efficient warm rain processes to drive these high rainfall rates. Expect locally as much as 3 to 5 inches of rain to be possible, with isolated heavier amounts where any cell-training occurs. Given the rather wet soil conditions from yesterday's rainfall, including USGS data showing high streamflows, these additional rains this morning are likely to cause some areas of flash flooding. Any urban corridor as well would be sensitive to seeing more enhanced runoff concerns. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6btXim6_YH4LdKVyV1-UBvm00zG0wQ5zoaSCISVFi3h1O2cUtZN3WAU5Tdnw7SMAmLUg= ir8f-ECYqKahJzL6qJ4pu9Y$ for graphic product... ATTN...WFO...CRP...EWX...FWD...HGX... ATTN...RFC...WGRFC...NWC... LAT...LON 30769661 30719575 30149498 29309493 28869547=20 28749571 28399639 28479693 28719727 29229760=20 29819758 30389728=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) .