Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun May 12 2024 11:55:42 AWUS01 KWNH 121155 FFGMPD TXZ000-121752- Mesoscale Precipitation Discussion 0257 NWS Weather Prediction Center College Park MD 754 AM EDT Sun May 12 2024 Areas affected...Central Texas east to the Piney Woods Concerning...Heavy rainfall...Flash flooding likely Valid 121152Z - 121752Z SUMMARY...Localized Flash flooding likely this morning from central Texas through the Heart of Texas into the Piney Woods as scattered heavy thunderstorms shift east along a low level boundary. DISCUSSION...Radar imagery at 1145Z showed a cluster of elevated heavy thunderstorms over the Central Texas Hill Country west of Waco with recent activity developing near/southeast of Waco. This activity has been moving ENE as 35kt SWly deep layer mean flow is counteracted by Wly upwind propagation vectors. Hourly rainfall of 2" has been estimated from KSJT and KGRK. This elevated activity is rooted in the 850-700mb layer above an inversion north of a warm front over south Texas with about 15000 J/kg of MUCAPE available. Upper level SWly flow is from a positively-tilted trough over CO/NM that is advecting Pacific moisture in across Mexico while low level flow over the warm front is bringing moist flow from the western Gulf of Mexico with PWs around 1.7" which is 2 sigma above normal. Guidance is generally too slow/behind on this activity with recent HRRRs depicting its typical morning cold/dry bias an unable to maintain this elevated convection from its warm start. However, the 00Z ARW2 seems to have a general handle on the situation and maintains and eastward expansion of of this ongoing activity into the Piney Woods through the rest of this morning. 1hr FFG is generally 2 to 2.5", but the area downstream of current activity is right in the axis of extreme rainfall over the past couple weeks that has caused major to in some places record river flooding, so this FFG is likely too high. The main limitation is shear with Wly 0-6km bulk shear values of 50kt which should maintain a somewhat scattered nature. However, given the sensitivity of this area, localized flash flooding should be expected. This boundary persists today as the warm front approaches from the south, so further heavy rain and flash flooding threats are forecast this afternoon across this area. Jackson ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8Vu_n6QPYvPKtyY6mAXLSbe5c9iFot7JqJ6L7LebUxvIwlmIuPHn9--mT74DnMcNA09N= -H5LZXwU7-ZvMtyxhe-w4k4$ for graphic product... ATTN...WFO...EWX...FWD...HGX...SHV...SJT... ATTN...RFC...WGRFC...NWC... LAT...LON 32249727 32129443 31129430 30879588 30979867=20 31229947 31899944 32139864=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) .