Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 26 2023 15:50:36 AWUS01 KWNH 261550 FFGMPD FLZ000-262145- Mesoscale Precipitation Discussion 0588 NWS Weather Prediction Center College Park MD 1149 AM EDT Mon Jun 26 2023 Areas affected...South Florida Concerning...Heavy rainfall...Flash flooding possible Valid 261550Z - 262145Z SUMMARY...Robust thunderstorms forming along the sea breeze front this afternoon are likely to contain excessive rainfall rates as high as 3"/hr. Flash flooding is possible with the more heavily urbanized locations most at-risk. DISCUSSION...GOES-16 visible satellite imagery shows a burgeoning field of towering cumulus over South Florida this morning. The 15Z surface observations show dew points are generally in the mid 70s and surface temperatures already above the 12Z MFL sounding's convective temp. Speaking of the 12Z MFL sounding, PWATs were up to 1.87" and the observed dew point of 76.4F was above the 90th climatological percentile according to SPC's sounding climatology. Warm cloud layers were approaching 12,000' in depth and mean cloud layer wind speeds were <10 knots. Thanks to strong surface based heating, MLCAPE will rise to >2,000 J/kg this afternoon while at the same time, PWATs increase to 2". The sea breeze front will act as the primary surface based trigger that will cause intense thunderstorms this afternoon. The lack of vertical wind shear will keep these storms relatively short lived. However, additional thunderstorm formation driven by air parcels punching above the LFC via surface based heating or from outflow boundaries being produced from the earliest forming thunderstorms are expected. The combination of adequate moisture aloft and plenty of instability may support max hourly rainfall rates as high as 3"/hr in the most intense cells. The Miami metro area has been no stranger to heavy rainfall in recent weeks with the more heavily urbanized locations feature 1-hr FFGs as low as 2.5". Some portions of the highly populated metroplex from West Palm Beach on south to Homestead have received as much as 2-5" above normal rainfall over the past 2 weeks. These hardest hit areas are most susceptible to possible flash flooding this afternoon, in addition to the more urbanized locations that contain a greater concentration of hydrophobic surfaces. Mullinax ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4iuUvy-91Vgj0kWk5iAfYhQjgrajVDwo3TJUxi1aLoqlK_BoDKpgJqOgQ1vK4_-WdMM7= JsCQMROjOrfCjWUWri1-UpA$ for graphic product... ATTN...WFO...MFL... ATTN...RFC...SERFC...NWC... LAT...LON 26918037 26827998 26248001 25778010 25568026=20 25288043 25258072 25498084 26118073 26638062=20 =20=20=20=20=20=20=20=20=20=20=20=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) .