Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
675 FXUS62 KKEY 240355 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1155 PM EDT Mon Sep 23 2024 ...New DISCUSSION, MARINE, AVIATION, TROPICAL SYSTEMS... .DISCUSSION... Issued at 1155 PM EDT Mon Sep 23 2024 Earlier this afternoon and continuing into this evening we have been seeing several quick rounds of showers and a few thunderstorms pulse across our waters at times. The latest round that entered the outer Gulf waters is on the downward trend and looks to be dissipating within the hour. Meanwhile, the outer Straits of Florida near Cay Sal Bank and points west are seeing showers pop up once again. These showers have been the result of the pressure gradient tightening up between a ridge located across the southeast U.S. and Potential Tropical Cyclone Nine. This is leading to an increase in winds which is acting upon the moisture rich boundary layer. Where speed convergence is greatest is where showers and thunderstorms have been seen. This is in addition to any previous outflow boundaries from convection across the southern mainland. That being said, outside of the aforementioned speed convergence, there is no large scale subsidence to lead to a more widespread coverage. With that said, will keep only a modest increase in PoPs overnight as we expect winds to gradually continue to increase leading to further convergence opportunities. Otherwise, as alluded to winds have begun increasing and are currently seeing 10 to 15 knots across the eastern waters with 15 to 20 knots starting to move into the western waters. Sadly, the easterly wind is keeping temperatures this hour in the mid 80s with dew points in the mid 70s. This is maintaining quite muggy conditions. && .MARINE... Issued at 1155 PM EDT Mon Sep 23 2024 Small Craft Exercise Caution headlines are in effect for most of the Florida Keys coastal waters. Moderate to occasionally fresh easterly breeze has developed this evening and will continue through the overnight and into Tuesday. This is in response to a high pressure building along the Eastern Seaboard, and PTC 9 in the northwestern Caribbean Sea. Heading through the middle and later part of the week, the forecast will depend on the development and movement of PTC 9. At this time, we expect fresh to strong east to southeast breezes to develop late Tuesday, with strong southeast winds peaking Wednesday night into Thursday as the tropical system moves northward across the eastern Gulf of Mexico. The strongest winds and highest seas are expected over western sections of the Keys waters. Mariners should continue to closely monitor the latest forecast updates during the next few days. && .AVIATION... (00Z TAFS) Issued at 1155 PM EDT Mon Sep 23 2024 VFR conditions will prevail through the overnight and into Tuesday morning. Shower coverage should gradually pick up but the timing for initiation remains uncertain at this time. The most likely time for the first showers to begin moving into the area should be around or after dawn. As PTC Nine moves northward through the day on Tuesday we should see winds increase especially for the EYW terminal and expecting southeast gusts near 25 knots towards Tuesday evening. Conditions will gradually deteriorate overnight Tuesday into Wednesday and Tropical Storm Force winds will most likely arrive by late Wednesday afternoon or evening for EYW. && .TROPICAL SYSTEMS... Issued at 1155 PM EDT Mon Sep 23 2024 At 1100 PM EDT, Potential Tropical Cyclone Nine (PTC 9) was centered about 430 miles south of Key West FL. The system is moving toward the north-northwest near 6 mph. A northwestward motion is expected on Tuesday and Tuesday night, followed by a faster northward to north- northeastward motion on Wednesday and Thursday. On the forecast track, the center of the system is forecast to move across the northwestern Caribbean Sea through Tuesday night, and then over the eastern Gulf of Mexico on Wednesday and Thursday. PTC 9 is still forecast at this time to pass west of Key West. Strengthening is expected during the next few days, and PTC 9 is forecast to become a hurricane on Wednesday and continue strengthening on Thursday as it moves across the eastern Gulf of Mexico. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Tropical Storm Watch for FLZ078. GM...Tropical Storm Watch for GMZ033>035-044-054-055-074-075. && $$ Public/Marine/Fire...LIW Aviation/Nowcasts....LIW Data Acquisition.....DR Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest