Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
836 FXUS62 KKEY 301756 AFDKEY Area Forecast Discussion National Weather Service Key West FL 156 PM EDT Mon Jun 30 2025 ...New DISCUSSION, MARINE, AVIATION, PREV DISCUSSION... .AVIATION... (18Z TAFS) Issued at 149 PM EDT Mon Jun 30 2025 VFR conditions will prevail at both island terminals through 18z Tuesday afternoon, with east to southeast winds generally 8 to 10 knots. Additional scattered showers with isolated thunderstorms may form this evening and overnight, although confidence in timing and evolution bars from inclusion in the TAFs for now. && .DISCUSSION... Issued at 1130 AM EDT Mon Jun 30 2025 Satellite-derived products continue to detect the beginning of the end for the latest Saharan Air Layer (SAL) event. The vast majority of the detected aerosols have advected west of the Island Chain, with the 12z morning sounding at KEY also supportive of this evolution. CIMSS mid- and upper-level vorticity products highlight cyclonic flow associated with a well-defined Tropical Upper Tropospheric Trough (TUTT) cell now centered north of the Bahamas continue to gradually slide westward towards the Florida Space Coast. Meanwhile, a second area of cyclonic flow associated with a weak troughing feature is located near the Big Bend region of Florida. The Florida Keys are sandwiched between these two features. Early morning showers and thunderstorms along a weak boundary slid through the coastal waters south of the Island Chain around sunrise, reached portions of the Middle and Upper Keys, then eventually dissipated before being able to affect most of the Lower Keys. KBYX radar is currently detecting little in the way of showers delivering measurable rainfall now at this late morning hour. For the rest of today, while there is likely some subsidence across the Keys CWA (owed to being on the periphery of these two cyclonic features), somewhat suppressed upper-level heights, along with a largely uninhibited environment should support additional scattered shower and isolated thunderstorm development, including any activity developing over South Florida possibly nudging southwestward. Mid-level chance rain and slight thunder chances still seems appropriate. Outside of the earlier increases to PoPs for the first period due to early morning radar trends, no changes proposed to the inherited current once-per-day overnight full forecast package. && .MARINE... Issued at 1130 AM EDT Mon Jun 30 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. Rain chances briefly taper back mid-week before increasing again late this week due to a new weather disturbance sliding into the Southeast US. && .FORECAST... Issued at 351 AM EDT Mon Jun 30 2025 The two features mentioned above will be quite the headache for our forecast through the end of the week. Despite a healthy and large TUTT, there is not really a surface reflection to speak of. This in combination with some residual low level dry air is likely contributing to a lack of rainfall. In addition, we will be going southerly just off the surface through the day, which tends to have a drying effect. That being said, if boundaries were to collide with enough force, the upper level support would aid in at least sustaining brief outbursts of convection. As a result, dropped rain chances as coverage looks to be limited and not all island communities will be affected today. Tonight as the low level steering flow remains southerly, we could see residual showers and thunderstorms come off Cuba and move northward over the island chain. Meanwhile, the TUTT will slowly move northwest, then north along the east coast of Florida Tuesday through Wednesday. As it pulls further away from the Keys, it will pull the moisture with it. This will lead to a gradual decline in rain chances through mid- week. However, this is where the headache continues. If you recall the aforementioned weak trough, this feature will gradually strengthen and push southward along the Florida Peninsula as a small upper level low. As it does, moisture will once again surge in across the area. At the same time, ridging across the Atlantic, will force this low to retrograde and briefly slide southwest into the Gulf late Friday into Saturday. Then it will slowly lift back northward over the weekend. This will keep the feature close enough that active weather looks more likely this weekend. Have begun the upward trend in PoPs for the upcoming holiday weekend. It remains too early to tell what may come about this weather disturbance if at all. Regardless of future development, this will remain relatively well to our north. For now, impacts to the Florida Keys will be limited to higher rain chances. && .PRELIMINARY POINT TEMPS/POPS... Key West 88 81 89 81 / 40 30 20 20 Marathon 90 82 91 82 / 40 30 20 20 && .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