Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 28 2025 18:12:48 AWUS01 KWNH 281812 FFGMPD LAZ000-ARZ000-TXZ000-290010- Mesoscale Precipitation Discussion 0093 NWS Weather Prediction Center College Park MD 211 PM EDT Fri Mar 28 2025 Areas affected...Eastern TX...Far Western LA Concerning...Heavy rainfall...Flash flooding possible Valid 281810Z - 290010Z SUMMARY...A localized threat for some flash flooding will exist going through the early evening hours from heavy showers and thunderstorms that may train over the same location. DISCUSSION...The early afternoon GOES-E visible satellite imagery shows an increasingly expansive CU/TCU field over eastern TX as vigorous mid-level shortwave/vort energy lifting northeastward interacts with a surface trough and the pooling of modest boundary layer instability. MLCAPE values are on the order of 500 to 1000 J/kg with a seasonably moist environment characterized by PWs of 1.5 to 1.75 inches. Radar does show a band of showers and thunderstorms organizing in a general south to north fashion over far eastern TX, and as additional diurnal heating/solar insolation contributions to further boundary layer destabilization this afternoon, there should be some additional expansion of convection which should tend to become locally well-organized given the presence of 30 to 40+ kts of effective bulk shear. This will include a convective threat to the middle and upper TX coast and the greater Houston/Galveston metropolitan area. The 12Z HREF guidance shows 50 to 70 percent probabilities of 1 to 2 inch/hour rainfall rates with the storms this afternoon, and some localized exceedance of 2 inch/hour rates will be possible especially for areas of far eastern TX just west of the LA border where the axis of stronger instability and relatively stronger surface moisture convergence is expected to be focused. Given concerns for some localized cell-training, some storm total amounts by 00Z (7PM CDT) may reach as high as 3 to 5 inches. FFG values across the region are rather high, but the HREF guidance does suggest some low end probabilities of exceedance which suggests a localized concern for flash flooding with an emphasis generally on the more urbanized locations. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4DhSf5ZuFUL6CbDwtUmz1GNmJBEXHXQ-9JjNoS51qiaJZGo1hr3MPnBVPVysW1AFUPks= qgc95sChMxDL4DpcXmOg54I$ for graphic product... ATTN...WFO...CRP...HGX...LCH...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 33089412 32769304 31189288 29729373 28859497=20 28499554 28399633 28699661 29309630 30539529=20 32419473=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) .