####018003124#### AWUS01 KWNH 020815 FFGMPD LAZ000-TXZ000-021413- Mesoscale Precipitation Discussion 0208 NWS Weather Prediction Center College Park MD 414 AM EDT Thu May 02 2024 Areas affected...central into southeast Texas, portions of southwestern/central Louisiana Concerning...Heavy rainfall...Flash flooding likely Valid 020813Z - 021413Z Summary...Complicated convective scenario will continue to pose a potentially significant flash flood risk through 14Z this morning. Discussion...The ongoing convective scenario is described by a couple of prominent linear segments - one about 50 miles NNE of Houston Metro and a second between Austin and Temple. Weaker convection persists between these two dominant linear segments, although the Austin/Temple complex has shown a weakening trend over the past hour - likely due to low-level trajectories from rain-cooled air over east-central Texas. The pre-convective environment (away from any outflow or ongoing convection) remains very moist (2 inch PW values) and unstable (~2000 J/kg MLCAPE), with strong southerly 850mb flow perpendicular to subtle outflows in vicinity of the convection to support occasional backbuilding/training. The complex has exhibited periods of both slow/nearly stationary and fast forward movement at times, enabling periods of 2-4 inch/hr rain rates and 5-9 inch storm totals across portions of the discussion area. Significant impacts have also been noted at times. The ongoing, complicated forecast scenario poses substantial uncertainty over the next 6 hours. Current thinking is that the ongoing linear complex northeast of Houston will maintain its intensity while moving east-northeastward toward southwestern Louisiana parishes through the morning. Continued backbuilding will occur between this MCS and an upstream MCV (centered near ACT/Waco) and continue to spread heavy rain and at least 1 inch/hr rain rates across water-logged areas that experienced 2-7 inches of rainfall earlier. These cells appear to be slightly elevated, which may be hindering intensity/rain rates in the short term. One key uncertainty regarding the ongoing scenario is whether convection can deepen near/south of US 290 between Austin and Houston, where better surface-based instability resides. Surface-based development in this region could result in upscale growth of another linear complex with training characteristics that promote both 1) 2-4 inch/hr rain rates at times while 2) potentially affecting more populated areas closer to Houston Metro. Although uncertain, a significant flash flood episode would be likely - especially if the the scenario depicted by the 06Z HRRR run were to materialize. Cook ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...EWX...FWD...HGX...LCH...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 32059373 31789276 31299209 30429200 29829265 29609512 29389661 30059761 30809806 31599753 31729677 31719584 31819500 32039443 ####018000937#### PENA01 KWNH 021200 @UHPISF000CN MPDSUM@V2.0@0101700060@12020524@@0NMCGPHMPD b@!' `' ` @ & B7)p&PNAM02@@CPJ~~}}{zzz{{|{~~~~~~~}~}~@@PJ@@PJ@@D*~||{{z{z{{{z{{z{z{z{{|}}~}~@@*@@*@@S0207 @@{0208 @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 05/02/2024 0814Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @####018000937#### PENA01 KWNH 021200 @UHPISF000CN MPDSUM@V2.0@0101700060@12020524@@0NMCGPHMPD b@!' `' ` @ & B7)p&PNAM02@@CPJ~~}}{zzz{{|{~~~~~~~}~}~@@PJ@@PJ@@D*~||{{z{z{{{z{{z{z{z{{|}}~}~@@*@@*@@S0207 @@{0208 @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 05/02/2024 0815Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @