Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 22 2024 23:13:46 AWUS01 KWNH 222313 FFGMPD FLZ000-230500- Mesoscale Precipitation Discussion 0108 NWS Weather Prediction Center College Park MD 713 PM EDT Fri Mar 22 2024 Areas affected...southern FL Peninsula and the Keys Concerning...Heavy rainfall...Flash flooding possible Valid 222312Z - 230500Z Summary...Flash flooding will be possible across portions of southern FL, including the FL Keys, through 05Z. Rainfall rates with an approaching MCS may exceed 2 in/hr along with localized totals of 3-5 inches (perhaps locally higher). Discussion...GOES East infrared and regional radar imagery at 2230Z showed an MCS to the southwest of the southern FL Peninsula. The coldest cloud tops and bulk of lightning strikes have been advancing toward the southeast, missing Key West by 50-100 miles to the west. However, ship observations showed a 1006 mb low was located ~110 miles west of Key West and moderate to heavy rain with embedded thunderstorms were occurring north of the low within a low level warm advection regime...north of an estimated warm front extending across the Keys (though ongoing convection was making the exact frontal placement difficult). Farther east, a supercell was observed over Biscayne Bay, tracking north near the barrier island marking the eastern edge of the bay. Warm rain processes were dominating this cell given the lack of recent lightning data and relative warm tops on infrared imagery. Short term trends indicate this cell may impact Key Biscayne and portions of Miami/Miami Beach in the short term with rain rates of 1-2 in/hr if it is able to survive. According to the SPC mesoanalysis, MLCAPE has not changed much since 18Z across southern FL, with the northern extent of the 500 J/kg contour reaching North Key Largo, coinciding with precipitable water values of 1.7 to 2.0 inches. As a mid-level closed low/trough over the Lower Mississippi Valley continues to track east into the early overnight hours, large scale lift will overspread FL, including increasing divergence/diffluence aloft. 925-850 mb layer southerly flow will likely increase at least another 10 kt from their present 25-30 kt values across southern FL, ahead of the approaching surface low west of Key West through 03-06Z. Widespread heavy rain will translate into southern FL from the west but additional convective development will be possible in advance as increasing moisture transport and CAPE overspread southern FL over the next few hours. Rainfall rates over 2 in/hr will be possible on a localized basis, especially with organized cells given favorable shear profiles, with storm totals of 3 to 5+ inches, perhaps focused near the Keys or the southern Everglades. There will be localized potential for higher rates along the urban southeastern corridor as well. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6P7cbMmN0G0uvK9FqJJ_EElCBaQMvqdyPjb5EX0_WVNyF5OHOThYvVXNeNHTzUNNfm2Q= x1OMxSaiVQ_xRT-A50hbR3E$ for graphic product... ATTN...WFO...KEY...MFL... ATTN...RFC...SERFC...NWC... LAT...LON 26758023 26547979 26107953 25007990 24308110=20 24178187 24438223 24848210 25428157 25918090=20 26628050=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .