Flash Flood Guidance
Issued by NWS
Issued by NWS
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579 AWUS01 KWNH 081753 FFGMPD KYZ000-ILZ000-MOZ000-082335- Mesoscale Precipitation Discussion 0240...Corrected NWS Weather Prediction Center College Park MD 152 PM EDT Wed May 08 2024 Corrected for GRAPHIC AND ATTN LINE FIX Areas affected...much of central and southern MO...southern IL Concerning...Heavy rainfall...Flash flooding likely Valid 081735Z - 082335Z Summary...Scattered to numerous instances of flash flooding are likely through late afternoon with additional localized totals of 2-4" expected. Discussion...A pair of intense supercells continue to track gradually eastward across central MO early this afternoon, producing 1-2"/hr rainfall rates along their path. These cells began as a single elevated intense supercell earlier this morning south of Kansas City, but the resulting cells have since become surface-rooted with daytime heating (and a slight southward drift in track). The mesoscale environment in the vicinity of these storms is characterized by an ML CAPE gradient of 1000-2500 J/kg, PWATs of 1.2-1.4 inches (already near the 90th percentile, per SPC sounding climatology), and effective bulk shear of 50-70 kts. Given that the original prolific supercell from this morning has already had a history flash flooding, the expectation is that flash flooding will remain likely into the late afternoon with an expansion in overall areal coverage (becoming scattered to numerous) as storm coverage increases (both downstream and upstream of current storms along the remnant outflow). Localized additional totals where cores train most efficiently is expected to be 2-4", generally exceeding short-term (3-6 hour) regional FFGs of ~1.5-2.5". This QPF corresponds with 12z HREF 40-km neighborhood probabilities for 3" exceedance of 20-40%. Churchill ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...LSX...PAH...SGF... ATTN...RFC...LMRFC...MBRFC...NCRFC...OHRFC...NWC... LAT...LON 39199010 39148894 38578873 38128845 37488825 37278873 37098929 37439034 37259164 37229334 37859394 38309325 38929133