Flash Flood Guidance
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Issued by NWS
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247 AWUS01 KWNH 051157 FFGMPD MOZ000-ARZ000-OKZ000-KSZ000-051800- Mesoscale Precipitation Discussion 0227 NWS Weather Prediction Center College Park MD 756 AM EDT Sun May 05 2024 Areas affected...Northeast Oklahoma through Central Arkansas Concerning...Heavy rainfall...Flash flooding likely Valid 051156Z - 051800Z Summary...An extensive MCS is spreading heavy rainfall southeastward across the discussion area, with 1-2.5 inch/hr rates noted (some spreading into very sensitive areas near/north of Houston Metro). Flash flooding is likely, and significant impacts are possible. Discussion...Intense convection across west-central and central Texas has evolved into an expansive linear segment extending from near Waco west-southwestward to Del Rio. Additionally, scattered convection has deepened in earnest across southeast Texas between College Station and Lufkin. Each of the storms are in a pre-convective environment characterized by moderate instability (1500 J/kg MLCAPE), abundant moisture (1.5-1.9 inch PW), and weak inhibition. Furthermore, enhanced low-level flow associated with a 40-kt southerly low-level jet was enhancing convergence along both the leading edge of the MCS in central Texas, while enabling strong updrafts along a remnant surface boundary in southeast Texas from convection 1-2 days ago. The net result of this pattern is an elongated, generally west-to-east oriented MCS with efficient rainfall rates (generally over 2 inches/hr in many areas) along with very slow southward movement, with localized training/repeating storms and cell mergers supporting very heavy rainfall. Unfortunately, some of these storms (especially over southeast Texas) were producing 2+ inch/hr rain rates over areas that experienced abundant (4-13 inch) rainfall totals over the past 72 hours, with sensitive ground conditions continuing to readily promote flash flooding. The ongoing scenario will continue to support areas of heavy rainfall with 2-4 inch/hr rain rates and totals exceeding 6 inches where training is most pronounced and rain rates can be prolonged. Again, sensitive and urbanized areas cannot handle this degree of rainfall given prior, significant flash flood impacts over the past several days. Another widespread flash flood episode is expected (especially across southeast Texas), and significant impacts are also likely. Cook ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ICT...LZK...SGF...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...NWC... LAT...LON 37169592 37049493 36819374 36549306 36399223 35939152 34919135 34319178 33839227 33229275 33229322 33639393 34949495 36109606 36559633