Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 15 2025 20:32:36 AWUS01 KWNH 152032 FFGMPD MOZ000-ARZ000-160100- Mesoscale Precipitation Discussion 1089 NWS Weather Prediction Center College Park MD 431 PM EDT Mon Sep 15 2025 Areas affected...North to South Central Missouri...Far north-central Arkansas... Concerning...Heavy rainfall...Flash flooding possible Valid 152030Z - 160100Z SUMMARY...Band of slow moving pulse-like convection with 1.5-1.75"/hr and widely scattered localized totals to 2"+ in 1-3 hours. Localized flash flooding and low-water crossing issues are possible through evening. DISCUSSION...A narrow ribbon of enhanced moisture and low-level theta-E is being squeezed by oblique passing of very broad/strong upper-level trough over much of the Northwest CONUS and return flow under the closed ridge over the Great Lakes. This ribbon of 1.5-1.75" extends along the Upper Mississippi River through MO into central Arkansas. Solid surface heating with temperatures into the low 90s over mid 60s Tds supported fairly unstable environment with 2000-2500 J/kg of MLCAPE along the eastern/upwind edge of the deeper moisture plume.=20 The deeper layer confluence, along with weakened cap resulted in initial thunderstorms, though recent uptick has been noted over a much longer length of the instability/moisture axis. Strong updrafts with numerous overshooting tops dotting the length of the convective line, from Shelby to Osage to Texas and to Howell county in MO, becoming more scattered further south where mid-level convergence is slightly reduced (nose of return flow across south-central MO). Very oblique right entrance divergence and subtle 20kt effective bulk shear may allow for some vertical disconnect to the up/downdraft couplets to support a few updraft cycles, though overall organization is fairly weak and cell longevity is likely to be limited to 1-2 hours. However, vertical loading to the downdraft and very slow cell motions may allow for rates of 1.5-1.75"/hr and may result in widely scattered 2"+ totals in less than 2hrs. Overall, the grounds are quite dry with 0-40cm relative soil moisture at or below 30%, so while FFG values are very high, they may be discounting the initial harder/impermeable nature before eventual infiltration occurs, and given the sheer rate, the initial runoff may be higher than expected, resulting in widely scattered flash flooding conditions, especially near low-water crossings that dot the area and therefore is considered possible over the next 3-4 hours. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5sLA42kk-nHBN0tFeRaAJbC4enJwgUEj0QCsqbVwwwsomzGDpA_wJQwe1ASN8uoMj4hn= BZpxv0YGVUH7RBYlY2rnthM$ for graphic product... ATTN...WFO...EAX...LSX...LZK...SGF... ATTN...RFC...KRF...MSR...ORN...NWC... LAT...LON 40379249 39809183 39149162 37979136 37299133=20 36429134 36109214 36389272 36909316 38189353=20 39829328 40369283=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .