Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
996 FXUS62 KKEY 201541 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1141 AM EDT Mon May 20 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1118 AM EDT Mon May 20 2024 The main stories this morning are the training thunderstorms and heavy rainfall. Before dawn the Lower Matecumbe area was the first focus, then Vaca Key near and after dawn, and now the Lower Keys. The profile sampled by the 12Z was juiced (PW ~2"), contained moderate ML instability and minimal inhibition, and EFF deep layer shear roughly oriented (WSW-ENE) parallel to a weak convergence zone, hence the heavy rainfall. Training cells have steadily back built and new updrafts have been favored on both the up and down shear vectors. The highest radar derived totals so far are 5 to 10", with some believable gauges approaching 7". Until we can get the northwest steering flow in here later this afternoon, likely more of the same for those areas that can recharge. When it rains, it pours. && .MARINE... Issued at 1118 AM EDT Mon May 20 2024 Scattered thunderstorms accompanied by heavy rainfall, frequent lightning, and small hail will persist across the coastal waters of the Florida Keys into the afternoon. By later this afternoon or this evening, thunderstorms will decrease in coverage as breezes veer to the northwest and increase. Tuesday through Wednesday, breezes will gradually shift to the east as high pressure in the western North Atlantic builds back in across the region. && .AVIATION... (15Z TAFS) Issued at 1118 AM EDT Mon May 20 2024 KBYX radar shows convection ongoing across the Middle and Lower Keys. This activity is being driven by an outflow boundary propagating slowly to the west. This activity will continue to lower CIGs to MVFR conditions with IFR possible. LIFR and IFR conditions are possible for VIS as thunderstorms continue to impact the area, especially MTH. For now, EYW remains quiet but we are watching thunderstorms off to the east that may backbuild towards the terminal over the next couple hours. Winds will be influenced by the convective environment with the strongest gusts occurring in and around thunderstorms. && .CLIMATE... So far today, Marathon has recorded 5.95 inches as of the 953 am observation. The previous record for the date was 1.68 inches set back in 1991. Rainfall records for MTH date back to 1950. && .PRELIMINARY POINT TEMPS/POPS... Key West 90 79 89 79 / 60 30 30 30 Marathon 89 80 89 80 / 60 30 30 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...CLR Aviation/Nowcasts....MJV Data Acquisition.....MJV Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest