Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 16 2023 23:58:57 AWUS01 KWNH 162358 FFGMPD FLZ000-170500- Mesoscale Precipitation Discussion 0194 NWS Weather Prediction Center College Park MD 758 PM EDT Sun Apr 16 2023 Areas affected...southern FL Concerning...Heavy rainfall...Flash flooding likely Valid 162357Z - 170500Z Summary...Thunderstorms with very heavy rain are expected to impact portions of southeastern FL late this evening/early tonight. Rainfall rates of 2-4 in/hr and totals of 3-6 inches will be possible which would likely lead to urban/flash flooding. Discussion...Fading visible satellite imagery, local radars and surface observations helped identify a couple of boundaries helping to focus convection as of 23Z across the southern FL Peninsula. Surface to 900 mb winds were convergent from Monroe into eastern Collier and western Broward counties with active thunderstorms along the northern portion of the convergent axis across Broward County. Widespread convection farther north has produced a U-shaped outflow boundary that extended from Palm Beach into northwestern Miami-Dade County, and then northwestward to the west of Lake Okeechobee. Slow moving convection has had a history of producing very high rainfall intensities with observed 1 to 1.5 inch totals in a 15 minute period and 3-4 inches per hour rates over eastern St. Lucie County within the past 1-2 hours. Moderately large MLCAPE of 2000-3000 J/kg and precipitable water values over 1.5 inches (SPC mesoanalysis data) along with divergent and diffluent flow aloft were aiding in the production of heavy rain. Over the next few hours, thunderstorms are expected to build southward, just behind the advancing outflow boundary and along the eastward advancing low level convergence axis to its south. Southwesterly LFC-EL layer winds and forecast southwesterly 850 mb winds will support areas of training heavy rain which will likely contain rainfall rates of 2-3 in/hr and locally in excess of 3 in/hr given the environment in place. Additional storm totals of 3-6 inches cannot be ruled out for some locations across the urban southeastern corridor. While the precise locations of heaviest rain remain a bit uncertain, potentially falling just west of the I-95 corridor, portions of Miami-Dade into eastern Broward counties have received an astonishing 10-25 inches of rain over the past week, increasing sensitivity to flash flooding on a local scale. Urban and flash flooding are considered likely. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-PLnROO6ZYwRKCwdosV-swx_cxwHgIBIDzTC6Lu7reHKrEjgjZJVb4-MoJS0ecdFRkdn= vfwmkAffCFJvP8xynVUyaDM$ for graphic product... ATTN...WFO...MFL...MLB... ATTN...RFC...SERFC...NWC... LAT...LON 27568041 27558016 27277996 26507985 25608010=20 25318042 25228078 25288105 25618106 26358079=20 26878065 27198055=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) .