Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Aug 13 2023 23:23:59 AWUS01 KWNH 132323 FFGMPD MOZ000-ARZ000-OKZ000-KSZ000-140530- Mesoscale Precipitation Discussion 0920 NWS Weather Prediction Center College Park MD 721 PM EDT Sun Aug 13 2023 Areas affected...portions of west-central and southwestern MO...southeast KS...far northeast OK and northwest AR Concerning...Heavy rainfall...Flash flooding likely Valid 132330Z - 140530Z Summary...Localized repeating of 1-2"/hr rainfall rates to result short-term (3-hr) totals of 2-4", and longer-term (6-hr) totals of up to 6". Scattered to numerous instances of flash flooding are likely (with some significant flash flooding possible). Discussion...Strong to severe thunderstorms are primed to proliferate across a broad, increasingly unstable warm sector this evening, stretching from portions of the Southern Plains into the Mid-Mississippi Valley. The mesoscale environment is characterized by a strong instability gradient (ranging from 2000-5000 J/kg of SB CAPE), highly anomalous tropospheric moisture (PWATs of 2.1-2.3 inches, or near the max moving average per SGF/TOP sounding climatology), and deep layer (0-6 km) shear of 30-45 kts. A complex evolution of convection is expected over the next 6 hours, with storms firing near the main front (over northeast KS and west-central MO), while a seperate wave of low pressure approaches from the west farther south (near the OK/KS border). This will likely result in renewed heavy rainfall for the sensitive Kansas City metro area, with areas farther south (mainly in southwest MO and surroundings) could be hit with multiple rounds of heavy rainfall. Peak rainfall rates of 1-2"/hr are generally expected, but localized training could result in isolated totals of up to 3" in an hour. Recent CAM guidance (including the 18z HREF and subsequent HRRR runs) have been in fairly good agreement with the evolution of rainfall through 05-06z. The aforementioned rainfall rates will likely lead to localized short-term (3-hr) totals of 2-4 inches, with 6-hr localized totals of 3-6 inches (per HREF PMM and 40-km exceedance probabilities). The highest confidence for these totals (especially the 6-hr totals) exist across southeastern MO and adjacent portions of KS/OK, with HREF 40-km neighborhood probabilities for 3" and 5" exceedance of 30-60% and 10-20%, respectively. In addition, HREF ensemble agreement scale (EAS) probabilities for 1" exceedance are as high as 30-60% as well (indicating good spatial agreement among the ensemble members). Antecedent conditions across this region are fairly wet (especcially across southeast MO, as indicated by NASA SPoRT-LIS 0-40 cm soil moisture anomalies in the 70-90th percentile), and associated Flash Flood Guidance (FFG) are as low as 1.5" and 2.0" (for 3-hr and 6-hr intervals, respectively). Given the expected rainfall totals and wet antecedent conditions, scattered to numerous instances of flash flooding are considered likely (with some significant, life-threatening instances of flash flooding possible). Churchill ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9PW7-uq9aS7rT5rWZ_MLiEXlJeCueQ2dzcgyIhqDkN_WrSxdOOua6pDTEftEqp8THqY3= o_bDi7kzlx5_7IWWGfsaQag$ for graphic product... ATTN...WFO...EAX...ICT...LSX...LZK...SGF...TOP...TSA... ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC... LAT...LON 39539488 39349370 38789269 38019118 36939131=20 36259212 36039317 36119459 36609584 37109633=20 37699661 38399682 39229671=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .