Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue May 23 2023 18:14:58 AWUS01 KWNH 231814 FFGMPD FLZ000-GAZ000-ALZ000-240000- Mesoscale Precipitation Discussion 0326 NWS Weather Prediction Center College Park MD 213 PM EDT Tue May 23 2023 Areas affected...FL Panhandle...Southeast AL..Southwest GA Concerning...Heavy rainfall...Flash flooding possible Valid 231800Z - 240000Z Summary...Clusters of slow moving showers and thunderstorms continue to evolve this afternoon across portions of the FL Panhandle northward. Periods of 2-3"/hour rainfall rates atop saturated soils from earlier storms could support flash flooding going into this afternoon.=20 Discussion...17Z subjective surface analysis placed a modified stationary front and wave along the western fringe of the Florida Panhandle, extending southwestward into Louisiana. Meanwhile, a secondary push of cooler air was noted to the north and west behind a backdoor cold front. The stationary front was favorably interacting with a weak shortwave over central Alabama to yield increasing coverage of slow moving clusters this afternoon across the Panhandle with added insolation. Single source and multi-sensor hourly rainfall estimates suggest this slow moving cluster activity is rather efficient, with estimated rates of 2-2.8"/hour noted. Recent mesoanalysis estimates of 2000-3000 J/kg SBCAPE and GPS PWAT estimates of 1.4-1.6" (above the 90th percentile moving average for this time of year) across the highlighted area imply very efficient rainfall rates upwards of 3"/hour should continue with additional convection this afternoon. Although weak vertical shear (20 kts according to KEVX VAD) will limit more robust individual updraft organization and longevity, easterly storm motions of 10-15 kts are oriented parallel to the low-level forcing (stationary front). Accordingly, the concern is for periods of backbuilding and training of efficient multi-cells along the front through the afternoon. The 12Z HREF corroborates this idea, and depicts an east-west oriented area of elevated (20-25%) chances of 5 year QPF ARI exceedance through 0z along the Panhandle, with an embedded 5-10% chance of 10 year QPF ARI exceedance also noted. While FFGs within the affected area are rather high (around 2-4"), rainfall totals of 3-4" are possible through 0z within the main axis of training. This suggests flash flooding is possible through tonight, especially given the 4-5" of prior rainfall over the last 24 hours. Asherman ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8xWI4urSUZCJv2WCtTAR6DbvdpeArXexpV-ozrGACI8G-YiqYMTRr6QEyF4sGx60YpRW= l0-CDI4pDMfdMQ7fu-vqwMY$ for graphic product... ATTN...WFO...MOB...TAE... ATTN...RFC...SERFC...NWC... LAT...LON 31428608 31298502 30838385 30048363 29528479=20 29688540 30088588 30268657 30138731 30288775=20 30678771 31198702=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) .