Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 09 2024 07:13:23 AWUS01 KWNH 090713 FFGMPD FLZ000-091230- Mesoscale Precipitation Discussion 1096...Corrected NWS Weather Prediction Center College Park MD 311 AM EDT Wed Oct 09 2024 Corrected for Summary statement Areas affected...Southwest Florida.... Concerning...Heavy rainfall...Flash flooding possible Valid 090700Z - 091230Z SUMMARY...Potential for coastal training rotating thunderstorms capable of 2.5"/hr rates and spots of 2-5" possible through morning. DISCUSSION...06z surface analysis along with BYX VWP and RADAR animation shows winds have veered to more southerly and starting to increase WAA, lifting the stalled boundary across southeast Gulf/Florida Bay northward. Upper 70s to lower 80s temp/dewpoints along the Florida Straits and the strengthening speed convergence with this warm air advection is allowing for increased instability advection northward expanding 2500+ J/kg SBCAPE values northward along the coastal boundary. SPC MCD and bulk shear values suggest main mode of shallow rotating thunderstorms along this band. While mean steering flow and approaching isallobaric influence would press cell motions further west, rotation and right movement is generally counteracting this influence and supporting a generally north or north-northeast cell motion for these thunderstorms allowing for a solid potential for training development given upstream moisture convergence in proximity of the lifting boundary and coastal frictional convergence may allow for this. While updrafts are narrow, the rotational flow increases speed and directional moisture flux into the updrafts allowing for intense low level moisture loading and therefore intense rainfall production. Overall moisture of 2.25-2.5", though clearly loaded in the sfc to 700mb layer will support efficient production with hourly rates of 2-3"/hr though inner cores will likely drive the majority of that rain in sub-hourly time frames (15-30 minutes) further increasing the potential for rapid inundation flooding across the flat/urban ground conditions. This is further compounding potential issues given recent moderate to heavy rainfall. NASA SPoRT 0-40cm soil moisture is well above normal at 70-80% capacity and generally above 95th percentile for the time period.=20 Much of the Hi-Res guidance suite does not place this warm advective training band ashore, but most have assimilated this band much further west than current trends would suggestion, with recent HRRR solutions slowly adjusting to RADAR with the 05z run getting closest, so far. So, while the band still may align along/just offshore with the most intense cores/training axis, the risk for this training band crossing the urban coastal zones has increased enough to suggest spots of 2-5", resulting in possible localized inundation flooding through early morning. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!616dJne68gZ0FK_N9zgLgg56Pwl21KkvT_oB9F_yiRk3kKVe4nDWG2nubPu104knwJLI= a-9Y3lAxgViYxvDHe-_P0fk$ for graphic product... ATTN...WFO...MFL...TBW... ATTN...RFC...SERFC...NWC... LAT...LON 27488254 27148203 26648165 26078099 25338037=20 25178105 25848176 26328196 26478225 27108255=20 27348270=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) .