Flash Flood Guidance
Issued by NWS
Issued by NWS
828 AWUS01 KWNH 112041 FFGMPD FLZ000-120240- Mesoscale Precipitation Discussion 0424 NWS Weather Prediction Center College Park MD 440 PM EDT Tue Jun 11 2024 Areas affected...South Florida Concerning...Heavy rainfall...Flash flooding likely Valid 112040Z - 120240Z SUMMARY...Slow-moving and locally training showers and thunderstorms with extreme rainfall rates will continue going into the evening hours. Flash flooding is ongoing across parts of south FL and this threat will continue into the evening hours with some expansion of the threat along the I-95 corridor from Miami to Fort Lauderdale expected. DISCUSSION...The late-day GOES-E IR satellite imagery in conjunction with dual-pol radar imagery shows numerous clusters of cold-topped convection with extreme rainfall rates impacting south FL, and especially the I-95 corridor of southeast FL around the Miami metropolitan area. The convection is focusing along a southwest/northeast orientation trough axis with a deep tropical airmass characterized by 2.5+ inch PWs and a tally skinny CAPE environment with MLCAPE values of 1500 J/kg. Rainfall rates with the ongoing activity have been extremely high and as high as 2 to 4 inches/hour with an extremely efficient environment favored by very high WBZ heights (over 15,000 feet) and persistent deep layer ascent that is also being supported by a 30 kt southwest low-level jet coming in off the southeast Gulf of Mexico. Given the latest satellite and radar trends, and output from the HRRR guidance, additional rainfall totals across south FL going through the mid-evening hours may reach 4 to 8 inches, with isolated storm totals potentially approaching or exceeding 10 inches. The urban corridor along I-95 from Miami to Fort Lauderdale will be at risk for locally significant and potentially life-threatening urban flash flooding given the extremely high rainfall rates and persistence of these training clusters/bands of showers and thunderstorms. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...KEY...MFL...MLB... ATTN...RFC...SERFC...NWC... LAT...LON 27088005 26367985 25717999 25178042 25118067 25198118 25528136 25748166 25948174 26298109 26648069 26968045