Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 05 2025 18:03:54 AWUS01 KWNH 051803 FFGMPD TXZ000-060000- Mesoscale Precipitation Discussion 0225 NWS Weather Prediction Center College Park MD 203 PM EDT Mon May 05 2025 Areas affected...central TX to middle/upper TX coast Concerning...Heavy rainfall...Flash flooding possible Valid 051802Z - 060000Z SUMMARY...Repeating and short term training of cells across central TX to the middle/upper TX coast may result in localized flash flooding through 00Z. Peak rainfall rates could be as high as 2-3 in/hr with isolated totals in excess of 4 inches. DISCUSSION...1730Z radar imagery showed a cluster of thunderstorms near Austin on either side of I-35, with an average cell movement off toward the northeast at 30-40 kt. Some new cell development has been observed south of ongoing cells, allowing for brief training with MRMS-derived rainfall of 1.0-1.5 in/hr over eastern Travis into Bastrop County. This area of storms was elevated, being forced by low level warm advection to the north of a wavy warm front at the surface, extending west to east across south-central TX. Layered PW imagery showed these storms were positioned along the northern edge of a surface to 700 mb moisture axis, drifting northward through central TX. SPC mesoanalysis and RAP guidance showed MUCAPE of 1000-1500 in the vicinity of Austin. 925-850 mb winds were from the south-southeast to southeast across the surface warm front at 20-30 kt (VAD wind plots) from central to southern TX and are forecast by the RAP to translate eastward toward Houston through 00Z. Steering flow should take ongoing thunderstorms toward the northeast with more organized cells right of the mean wind. Meanwhile, additional development is likely to fill in between the ongoing activity and the surface warm front which is expected to lift north during the afternoon. Overrunning of the front and low level convergence on the nose of stronger low level flow (which may align with steering flow at times) will favor repeating cells with short term training and potential for rainfall rates of 2-3 in/hr. Flash flooding will be possible with storm totals over 4 inches on a localized basis which will pose a risk of flash flooding, with the greatest threat over urban locations due to relatively high 3-hr flash flood guidance values of 3 to 5 inches. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_P0YKSKTL1gBtls5rF98gmbdey2EVPC3rWrgH2gGbCZnOs0wj-JR92VvuRDltHfx9usZ= H9YRdgB0Dr9f3m-5LimiX_c$ for graphic product... ATTN...WFO...CRP...EWX...FWD...HGX...LCH... ATTN...RFC...WGRFC...NWC... LAT...LON 31119726 31079636 30629535 30219460 29649428=20 29089435 28779486 28549571 28469634 28469740=20 28909836 29479873 30169871 30869804=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) .