Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Nov 15 2023 17:16:24 AWUS01 KWNH 151716 FFGMPD FLZ000-152200- Mesoscale Precipitation Discussion 1172 NWS Weather Prediction Center College Park MD 1215 PM EST Wed Nov 15 2023 Areas affected...Florida Keys Concerning...Heavy rainfall...Flash flooding possible Valid 151715Z - 152200Z SUMMARY...Multiple bands of heavy rain will merge over the Keys through the early afternoon, resulting in increasing rainfall rates as high as 3 inches per hour. Heavy rain and high tides could combine to result in localized flooding in sensitive areas. DISCUSSION...A developing mesolow over the Gulf has caused a northeast-to-southwest-oriented line of thunderstorms to develop west of Dry Tortugas in advance of the low center, moving eastward towards the Lower Keys. Meanwhile a nearly stationary southeast-to-northwest-oriented band of rain has embedded northwestward-moving convection capable of 3 inches per hour rainfall rates over the Middle to Upper Keys. Through the early afternoon hours, much of the high-resolution guidance suggests these two bands will merge and increase convective organization over the Keys, resulting in more widespread convective rainfall. PWATs through the morning have been increasing over the Keys as high as 2.25 inches. Southeasterly surface winds have increased with gusts as high as 40 mph at Sombrero Key. This persistent flow over the Florida Straits will limit drainage of the heavy rains off the Keys, and keep the tides elevated for longer than normal. Slow-moving and/or training convective cells moving over the Keys in concert with higher than normal tides could result in localized ponding and drainage flooding, particularly should those heavier cells set up over urbanized Key West or Key Largo. Any flooding would be the result of a combined tidal and heavy rains, preventing adequate drainage off the Keys. The flooding threat should gradually shift north and east up the Keys and into the southern Mainland through mid-afternoon as the aforementioned surface low tracks near or over the Keys. The low will end the heavy rainfall threat from west to east, while enhancing rainfall rates north and east of the center, which will be the main driver for heavier rainfall into the urban corridor of South Florida late this afternoon through the evening. Wegman ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-IQtgPO9SiOYQR3ZGoj-gFRWKPnMcFE_xJEXtzo_UmKOz7Dxid5NGD4Ou8_78BWSWKmR= z81IdB6BOBid1fMBtPQSxm4$ for graphic product... ATTN...WFO...KEY...MFL... ATTN...RFC...SERFC...NWC... LAT...LON 25548014 24878006 24328094 24188237 24758250=20 24878183 25058077 25448049=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) .