Flash Flood Guidance
Issued by NWS
Issued by NWS
291 AWUS01 KWNH 112226 FFGMPD FLZ000-120224- Mesoscale Precipitation Discussion 0425 NWS Weather Prediction Center College Park MD 625 PM EDT Tue Jun 11 2024 Areas affected...West-Central FL Concerning...Heavy rainfall...Flash flooding likely Valid 112224Z - 120224Z SUMMARY...Extremely heavy rainfall associated a nearly stationary low center just southwest of Tampa Bay is expected to pose a short-term urban flash flood threat from Bradenton down to Sarasota. DISCUSSION...Late-day GOES-E visible satellite imagery along with dual-pol radar shows a nearly stationary low center southwest of Tampa Bay over the far eastern Gulf of Mexico. Rather strong moisture convergence focused in around the southeast flank of the low center along with a moderately unstable airmass with MLCAPE values of 1500 to 2000 J/kg has been resulting in a persistent and concentrated band of very strong convection with extremely heavy rainfall rates. The cloud top temperatures with the convection have been as cold as -70 to -75C, and with a highly tropical environment with PWs pushing 2.25+ inches, some of the rainfall rates have been reaching 3 to 4 inches/hour over the last hour. Part of the convective band is offshore, but part of it over the last hour has edged onshore and is impacting the urban corridor from near Bradenton southward down through Sarasota. Recent radar trends suggest some northward advance of the convective band with the low center also showing some evidence of deepening somewhat which suggests the ongoing convective organization, albeit it sheared, over the southeast part of the low center may maintain itself in response to stronger low-level convergence/forcing. This suggests at least in the near-term that extremely heavy rainfall rates within this convective band may continue to edge farther inland and persist, with impacts in particular along the Bradenton to Sarosota urban corridor. Given extremely high rainfall rates of 3 to 4 inches/hour, some storm totals over the next 2 to 3 hours may locally approach or exceed 6 to 8 inches. Urban flash flooding is considered likely given the set-up, and this situation will need to be closely monitored going into the evening hours. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...TBW... ATTN...RFC...SERFC...NWC... LAT...LON 27928261 27718218 27388201 27078202 26988235 27258266 27718280