Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 12 2025 07:00:13 AWUS01 KWNH 120700 FFGMPD FLZ000-121100- Mesoscale Precipitation Discussion 1073 NWS Weather Prediction Center College Park MD 259 AM EDT Fri Sep 12 2025 Areas affected...east coast of FL Concerning...Heavy rainfall...Flash flooding possible Valid 120658Z - 121100Z Summary...Localized flash flooding will be possible along the east coast of FL from nearly stationary cores of heavy rain through 11Z. Hourly rainfall totals of 2 to 3+ inches and localized total rainfall of over 4 inches may occur. Discussion...Reflectivity from KMLB and KAMX showed an axis of heavy rain aligned along and just offshore of the FL Peninsula, from Saint Lucie to Palm Beach counties. A lack of lightning within this axis inferred warm rain processes ongoing with estimated PWs of 2.0 to 2.3 inches and 1000-2000 J/kg MLCAPE via 06Z SPC mesoanalysis data. MRMS-derived hourly rainfall has been in the 1.0 to 2.5 inch range over the past 2 hours. The rainfall appears to have formed along the land breeze boundary and water vapor imagery helped identify a subtle vorticity max between Grand Bahama and Palm Beach County, helping with lift across the region. There may also be right-entrance region divergence aiding lift, tied to a jet max positioned just off of the Carolina coast. VAD wind plots showed that onshore flow in the 925-850 mb layer was from the northeast, with advection of unstable air from the warm offshore waters pushing slightly inland. Weak steering flow was supporting slow net movement of cells. In addition, a weak surface low may be forming along a stationary front draped east to west across the southern Peninsula with return flow focused into the coast, to the north of the low. West to southwest flow aloft implies the vorticity max should advance farther away from the coast over the next few hours but some degree of onshore flow will remain in the short term, supporting the potential for continued slow moving/nearly stationary cores of heavy rain along the coast from roughly Palm Beach County to southern Brevard County. The environment favors the continued potential for hourly rainfall from 2 to 3+ inches and storm totals possibly over 4 inches. However, this flash flood threat looks to be rather localized and short term, focusing the greatest impacts with overlap of the urban corridor. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!61ZNJoEs-0noFmVEDkY0TkfuRlJDFZHrDAuTCoLazWNx_98B_rJgQgggtvP-5HOxIQdi= Qb7ZAb-KCOaDzoXB2kmjI6E$ for graphic product... ATTN...WFO...MFL...MLB... ATTN...RFC...ALR...NWC... LAT...LON 28348050 28158019 27687992 27137982 26727975=20 26177984 26258022 27068038 28178072=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .