Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Apr 06 2023 16:19:01 AWUS01 KWNH 061618 FFGMPD LAZ000-TXZ000-062130- Mesoscale Precipitation Discussion 0163 NWS Weather Prediction Center College Park MD 1218 PM EDT Thu Apr 06 2023 Areas affected...south-central, central, eastern TX into far northwestern LA Concerning...Heavy rainfall...Flash flooding possible Valid 061617Z - 062130Z SUMMARY...Repeating rounds of heavy rain are expected to impact portions of central to eastern TX over the next few hours while renewed development is possible over south-central TX. Rainfall rates of 1-2 in/hr are likely where cell training occurs, but locally higher rates will also be possible. DISCUSSION...Local radar imagery across central TX helped identify two MCVs 50-75 miles east of San Antonio and just south of I-10 at 1530Z. The mesoscale circulations were associated with areas of enhanced convergence and higher rainfall rates of 1-2 in/hr, locally higher per MRMS data, with a broader stratiform region of rain to the immediate north of the MCVs, extending from the Hill Country into eastern TX and northern LA. Aloft, the right entrance region and an area of strong upper level divergence tied to a powerful upper level jet was located over central TX, but with the jet core over the Plains/Midwest translating northeastward. Flow was also diffluent around the core of the coldest cloud tops which have shown some warming over the past 60-90 minutes. Showers and thunderstorms were located along the 925-850 mb reflection of a quasi-stationary surface front in the western Gulf of Mexico, with steering flow generally parallel to the elevated front. The MCVs are likely to hold together for at least another couple of hours as they advance off toward the northeast into a region of weakening MUCAPE, initially near 1000 J/kg but reducing to 500 J/kg or less through 21Z as forecast by the RAP. The potential for locally heavy rain with rainfall rates of 1 to 2+ in/hr will remain just ahead of the advancing MCVs as they track toward eastern TX, possibly resulting in areas of flash flooding. To the southwest of the main area of rainfall, over south-central TX, MUCAPE of 500-1000 J/kg was estimated at 15Z (SPC mesoanalysis) and forecast to remain into the short term via RAP/HRRR forecasts given steep 700-500 mb lapse rates of 7.0-7.5 C/km. Continued low level overrunning of the surface boundary is expected to converge along the elevated front, resulting in additional convective development by 21Z. There is uncertainty with the coverage and intensity of the anticipated convection but portions of south-central TX into eastern TX have picked up 3-6 inches of rain over the past 24 hours. Localized flash flooding will be possible over the next 3-6 hours, especially if cells overlap with locations that have already received heavy rain over the past 24 hours. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7zPYT5Buq9RZ2LDdIJ4LtF6jtUocAAe_t70v_NI12gyBF_BOjtQWEpTEcBCWJvVWzF0u= Huho1N9wduFYQKaesiF4Mhs$ for graphic product... ATTN...WFO...CRP...EWX...FWD...HGX...LCH...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 32649392 32219336 31519362 30589500 29499651=20 28609784 28119855 28169895 28499917 29309901=20 29989861 31089740 32489509=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) .