Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
308 FXUS62 KKEY 291858 AFDKEY Area Forecast Discussion National Weather Service Key West FL 258 PM EDT Sun Jun 29 2025 ...New AVIATION AND MARINE... .AVIATION... (18Z TAFS) Issued at 243 PM EDT Sun Jun 29 2025 Despite bouts of BKN180 ceilings, VFR conditions will prevail at both island terminals through 18z Monday afternoon. Scattered showers and isolated thunderstorms will be possible, mainly after 12z Monday, although confidence in initiation time and evolution bars inclusion in the TAFs at this time. Near- surface winds will remain out of the east to southeast at 9 to 11 knots && .MARINE... Issued at 243 PM EDT Sun Jun 29 2025 No watches, warnings, or advisories are currently in effect for the coastal waters of the Florida Keys. From synopsis, broad low- level ridging will continue to rebuild over the North Atlantic and support gentle to moderate east to southeasterly breezes across Florida Keys coastal waters, veering to the southeast to south and modestly slackening throughout the week. An upper- level low east of the Bahamas will slide slowly northwestward towards the Florida east coast early this week, supporting slightly enhanced rain and thunder chances. A return to near- normal rain and thunder chances is expected for Wednesday through the end of the work week. && .PREV DISCUSSION... Issued at 1136 AM EDT Sun Jun 29 2025 Composite regional satellite analysis highlights pockets of low cumulus clouds streaming towards the Florida Keys in the mean boundary layer east to southeasterlies. Meanwhile, further aloft, a pretty thick deck of cirrus clouds are diving southwestward associated with a tropical upper tropospheric trough (TUTT) cell centered east of the Bahamas. The 12z morning sounding at KEY continued to sample a well-defined Saharan Air Layer (SAL) signature, with very dry air embedded in the 500-900 mb isobaric layer. The cirrus deck is doing little to hold temperatures in check, with surface observations along the Island Chain reporting temperatures in the upper 80s on this late June morning. KBYX radar is void of any meteorological echo returns. Given the immense SAL-induced dry air, as well as the dense cirrus deck satellite trends and upstream, elected to lower PoPs and nudge sky cover upward for the first period. Other than that, no changes proposed for this late morning update iteration. && 200 .FORECAST... Issued at 440 AM EDT Sun Jun 29 2025 A quiet start to the weekend is underway for the Florida Keys this morning. KBYX radar is clear of any precipitable echoes as showers from yesterday evening have long since dispersed. GOES-19 Nighttime Microphysics RGB imagery depicts lines of shallow cumulus drifting towards the Keys with some high cirrus bubbling in from the south. Sensible weather conditions are quite similar to 24 hours ago with temperatures along the island chain in the lower to mid 80s and dewpoints in the upper 70s. Moderate east to southeast breezes prevail on the Reef tract reinforced by high pressure nosed over mainland Florida. A few more shallow lines of low clouds appear upstream but looks notably drier than this time yesterday. The big weather story today for the Keys is the Saharan Air Layer (SAL) currently advecting into our area. With the mid to upper level trough from last week losing its influence to ridging building back into the area, the SAL riding along the periphery of the previously mentioned ridge finally makes its pass across the Keys this weekend. While our 00z balloon sounding from yesterday evening was too early to capture the dry air filtering in aloft, CIMSS MIMIC TPW shows drier values present over the Florida Keys this morning. This is also supported by a lack of precipitation in our CWA. While this forecast is about as dry as it can get for this time of year, wet season likes to be somewhat unruly when it comes to convective development so have opted to go with dime PoPs with a slight chance of thunder over the next 24 hours or so to cover possible isolated incidents of showers popping up briefly. Rain chances will return to near normal Sunday as the SAL pushes west past the Keys. PoPs will further increase at the start of the week as yet another upper level trough cycles its way towards the Keys. Guidance looks to place this feature on our doorstep sometime Monday along with both a surface reflection and a fresh undulation of tropical moisture. Of course, there is still uncertainty in both the exact placement of synoptic players here along with moisture available for convection, so PoPs have been merely nudged up for Monday and Monday night to note the period most likely to see rain according to recent model runs. This timing will continue to be refined as we approach the start of the week. As for the rest of the forecast period, seasonal temperatures and PoPs are currently on tap. && .PRELIMINARY POINT TEMPS/POPS... Key West 88 81 89 81 / 10 20 30 40 Marathon 89 81 90 81 / 10 20 40 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT Aviation/Nowcasts....BT Data Acquisition.....BT Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest