Flash Flood Guidance
Issued by NWS
Issued by NWS
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184 AWUS01 KWNH 082101 FFGMPD MOZ000-ARZ000-OKZ000-KSZ000-090300- Mesoscale Precipitation Discussion 0242 NWS Weather Prediction Center College Park MD 501 PM EDT Wed May 08 2024 Areas affected...Northeast OK...Southern MO...Northern AR... Concerning...Heavy rainfall...Flash flooding possible Valid 082100Z - 090300Z SUMMARY...Very strong moisture convergence into an pocket of enhanced moisture along/northeast of low level wave to allow for initially slow moving cells capable of 1.5-2"/hr rates. Spots of 2-3" in 2-3hrs pose possible flash flooding. As the line evolves incidents of repeating may occur as line flattens to the mean steering flow. DISCUSSION...20z surface analysis denotes a surface low along/just northeast of the dryline intersection across NE OK with a warm sector bounded to the north by warm front re-enforced by outflow in wake of late morning`s convective cluster, with a surface wave/effective TROWAL extending northward across west-central MO. GOES-WV and CIRA LPW suggest broad EML has begun to wash over the area, steepening lapse rates and increasing unstable environment with 3000+ J/kg of MLCAPE; yet RAP analysis and LPW also denote an enhanced pocket of moisture through greater depth down-shear of the wave and with low 70s Tds and total PWATs nearing 1.5", ample moisture flux should allow for increasingly efficient rainfall production. Currently, very strong moisture convergence is analyzed cross SW MO with surface winds gusting to 15-20kts, though direction is limited until reaching outflow boundary/frontal zone to the north. As such, expect increasing convective coverage over the next few hours. Rates initially have been should continue to be in the 1.5"/hr range; and given effective bulk shear is allowing for solid cell rotation, forward progression is initially going to be slow allow for some duration to allow for stripes of 2"+. Additionally, there is solid trends in WV imagery for flattening west to east cell motions while propagation vectors remain northeast to suggest cell mergers/repeating may become more consistent across S MO and perhaps far northern AR. Combined with rates increasing to 1.75-2"/hr should allow for 2-3" totals in 2-3 hour increments before line starts to propagate east-southeast into late evening. This places the area of concern within reach of exceeding broad 1.5"/hr and 2-2.5"/3hr FFG values. As such, scattered incidents of flash flooding are considered possible Gallina ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...LSX...LZK...MEG...PAH...SGF...TSA... ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC... LAT...LON 38179086 37788981 36918933 36358972 36079076 35909217 35679391 35609494 35909570 36489552 36969480 37919300