Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
771 FXUS62 KKEY 301831 AFDKEY Area Forecast Discussion National Weather Service Key West FL 231 PM EDT Tue Sep 30 2025 ...New AVIATION... .AVIATION... (18Z TAFS) Issued at 231 PM EDT Tue Sep 30 2025 VFR conditions will prevail at both EYW and MTH for the rest of today and into tonight. While a stray shower cannot be ruled out, low coverage and high uncertainty of timing will keep mention out of either TAF. Near surface winds will be out of the west to northwest at near 10 knots with occasional to frequent gusts up to 15 to 20 knots, before veering and slackening overnight. && .PREVIOUS DISCUSSION... Issued at 1125 AM EDT Tue Sep 30 2025 Mostly clear skies prevail across the Florida Keys on this final morning of September. GOES-19 visible imagery notes fair weather cumulus dotted along broken lines stretched across the island chain. A small meso low circulation can also be spotted in our deep Gulf waters drifting southeast. Meanwhile, KBYX radar detects a few shallow showers pulsing along these boundaries. These showers have generally remained offshore resulting in a fairly dry start to the day. Moderate west to northwest breezes are observed along the Reef and after a brief uptick from this morning seem to be fairly stable for now. While the drier conditions and northerly influenced wind direction may make it seem like a fall day outside, temperatures in the mid to upper 80s remind us that it is still September, especially with dewpoints in the mid 70s. This morning`s KKEY 12z sounding was another dry one with a PW value below the 25th percentile for today. CIMSS MIMIC PW confirms this with a clear streak of low values situated over most of the island chain. The current low level wind direction will continue to advect dry, modified continental air over the Keys today resulting in slight chance PoPs for the rest of the day. As Tropical Storm Imelda is progged to drift east into the North Atlantic, breezes will gradually slacken and veer starting tonight. Moderate west to northwest breezes will become gentle to moderate and more northerly overnight into tomorrow. Residual moisture from Imelda as well as a more moist wind direction will slide PoPs up to more seasonable values later tonight and into tomorrow. High pressure building along the Eastern Seaboard will gradually shift conditions back to near normal by the end of the week. && .FORECAST... Issued at 407 AM EDT Tue Sep 30 2025 As Imelda continues to move north and then makes it sharp turn to the east, high pressure will gradually fill in behind. This will allow the pressure gradient to eventually lessen and winds will slacken. At the same time, winds will periodically fluctuate between northwest to northeast as the building ridge battles with daytime heating across the Florida Peninsula at times. Moisture wrapping around the broad cyclonic envelop associated with Imelda will occasionally pivot across the region. That being said, rain chances will still be near normal. The only exception may be the Upper Keys where convection will tend to drift off the mainland, given a northerly steering flow. As we go through the first several days of October, the high will build as it pushes east and press against the Keys. This will allow for easterly winds to return, however, the exact strength will depend on how far south the high builds. The ECMWF at this point as a weaker high and thus lighter winds with a southeast tendency. The GFS is much stronger with the potential of moderate to fresh breezes returning. Another feature we will have to eventually keep an eye on will be a quasi-stationary frontal boundary that will develop as the high builds. This feature should stay well to our north but it could have impacts to our rain chances later in the period. && .MARINE... Issued at 1125 AM EDT Tue Sep 30 2025 A Small Craft Advisory remains in effect for the eastern Straits of Florida. From synopsis, Tropical Storm Imelda, located east of the northeast coast of Florida, will continue to move slowly northward, then make a sharp eastward turn today into the west- central North Atlantic. Moderate to fresh northwesterly breezes will slacken by tonight. High pressure over the Eastern Seaboard will slowly slide eastward into the western North Atlantic, with mainly gentle northwesterly breezes eventually veering to the northeast to east for the middle to latter part of the work week. Winds will then clock around towards the southeast towards the end of the week and into the upcoming weekend. && .PRELIMINARY POINT TEMPS/POPS... Key West 79 88 79 89 / 20 20 30 30 Marathon 79 88 79 87 / 30 30 30 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory until 9 PM EDT this evening for GMZ052-072. && $$ Public/Marine/Fire...JAM Aviation/Nowcasts....JAM Data Acquisition.....JAM Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest