Flash Flood Guidance
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Issued by NWS
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797 AWUS01 KWNH 272328 FFGMPD ILZ000-MOZ000-IAZ000-280526- Mesoscale Precipitation Discussion 0187 NWS Weather Prediction Center College Park MD 727 PM EDT Sat Apr 27 2024 Areas affected...central/northern Missouri, southeastern Iowa, western Illinois Concerning...Heavy rainfall...Flash flooding possible Valid 272326Z - 280526Z Summary...Scattered convection continues to produce spots of 1-2 inch/hr rain rates from east-central Kansas into north-central Missouri. At least an isolated flash flood risk will exist in this regime as storms move eastward toward the Mississippi River Valley through the early evening. Discussion...A complicated convective scenario continues to unfold across the discussion area. A convective cluster over north-central Missouri had produced areas of 1-2 inch/hr rain rates at times over the last few hours, and continues to do so across north-central Missouri west of Kirksville at this time. Upstream, a separate area of convection continues to deepen near/east of the Kansas City area that is likely tied to 1) strong low-level warm advection from 25-40 kt 850 flow across Missouri and 2) an approaching convective complex across southeastern Kansas. The airmass downstream of these storms was quite unstable/moist (2000+ J/kg MLCAPE and 1.3+ inch PW values) and weakly inhibited, which should continue to support thunderstorm development downstream toward the Mississippi River Valley through 03-05Z. Although the overall scenario supports deep convection and heavy rainfall, mechanisms for training/repeating are unclear except for on a very localized basis (for instance - west of Kirksville). This appears to be a limiting factor for a larger flash flood threat in the short term, although trends will need to be monitored for cell mergers, or perhaps isolated cells that can develop out ahead of ongoing convection and merge, prolonging rain rates in a few local areas. FFG thresholds are in the 1.5-2 inch/hr range, and should be approached on at least a localized basis as storms migrate east-northeastward across the discussion area. Flash flooding is possible with this scenario through 05Z. Cook ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...DMX...DVN...EAX...ILX...LSX...SGF... ATTN...RFC...MBRFC...NCRFC...NWC... LAT...LON 41519075 41228980 40278958 39179036 38549205 38489394 39149456 40309428 41089318 41359228