Flash Flood Guidance
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Issued by NWS
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445 AWUS01 KWNH 190037 FFGMPD OKZ000-KSZ000-190606- Mesoscale Precipitation Discussion 0462 NWS Weather Prediction Center College Park MD 837 PM EDT Tue Jun 18 2024 Areas affected...Southwest Kansas...Oklahoma Panhandle Concerning...Heavy rainfall...Flash flooding likely Valid 190036Z - 190606Z Summary...A semi-discrete line of supercell thunderstorms continues to evolve along the triple-point in Southwest Kansas. Training combined with slow storm motions of 5-15 kts may lead to locally very heavy rainfall upwards of 5-6" through 6z. Discussion...Radar across Southwest Kansas shows a broken line of semi-discrete supercells which emerged from an initially linear slab of convection along a slow moving cold front. Recently, the orientation of these supercells has started to align along a more west-east axis, and are exhibiting a training and backbuilding signal along the KS-OK border near the Liberal, KS area as new deep convection forms along a now retreating dryline and stalled cold front. Recent mesoanalysis estimates depict a very unstable environment upstream of the convection, including 3000-4000 J/kg MUCAPE and 1.4-1.6" PWATS. Effective shear values are a bit on the weak side (20-25 kts), although storm-relative anvil layer flow to the northeast may alleviate the lack of overall shear as storms move eastward along the Bunkers RM vector. Combined with strong low-level theta-e advection and increasing 1000-850 mb moisture convergence, the concern is for backbuilding and training on the southwest flank of the ongoing activity to continue going into tonight. The HREF continues to be quite aggressive going into tonight with this current activity, and shows very high (60-70%) probabilities of 6 HR QPF exceeding 3" through 6Z over Southwest Kansas, with an appreciable (30-35%) chance of 100 year ARI exceedence noted there. While antecedent conditions are generally dry across the region (according to NASA SPORT soil moisture percentiles), this focused corridor of very heavy rainfall will likely drive a risk of flash flooding through 6Z, some of which may be locally considerable. Asherman ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...AMA...DDC...OUN... ATTN...RFC...ABRFC...NWC... LAT...LON 37620029 37529966 37219959 36999976 36800022 36680073 36620119 36690167 36970183 37330175 37510115