Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
381 FXUS62 KKEY 260823 AFDKEY Area Forecast Discussion National Weather Service Key West FL 423 AM EDT Wed Jun 26 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 423 AM EDT Wed Jun 26 2024 Scattered showers have developed during the late night hours around the Upper Keys and over the offshore Gulf waters, apparently along leftover island streamer boundaries that have likely lurked since Tuesday afternoon. Temperatures along the Keys island chain are mostly in the lower 80s, with dewpoints in the mid to upper 70s, and winds on land from the southwest to west around 5 mph. Surface analysis depicts weak high pressure over the western Atlantic, with a ridge extending westward through the Straits of Florida. Aloft, a weak trough remains in place over the SW Atlantic, with a ridge extending eastward from Texas into the central Gulf of Mexico. The 00Z Key West sounding sampled a very moist and conditionally unstable airmass, with PW of 2.19 inches which is above the 90th percentile for the date. Recent MIMIC-TPW satellite imagery shows 2+ inch PWs remaining in place around the Keys, while somewhat drier air intrudes into the northern and eastern Gulf. Weak WSW low level flow, ample moisture in place, and the lack of a dominant ridge aloft all should favor island cloud line development again today, with above average potential for waterspouts. Accordingly, have maintained somewhat above climo 40 percent PoPs. However, have maintained just slight thunder chances, as the rather warm temps aloft have resulted in little lightning activity across our area during the past few days. Otherwise, expect high temps to reach near 90, with sticky dewpoints in the mid to upper 70s and light breezes making for a typically oppressive late June day. The ridge axis will begin to shift back northward across the Keys on Thursday, shifting our steering flow to the SSW. This should reduce the island cloud line potential, with best rain chances probably occurring in downwind streamers over the Bay and Gulf side waters. The lower to mid level ridge will also build westward from the Atlantic across our area beginning on Thursday, likely resulting in a somewhat suppressed convective pattern. Have kept the existing 20-30 percent PoPs from Thursday through Friday night, as the ridge should maintain more of an influence during this period. For the weekend and into early next week, the ridge aloft is forecast to weaken, with moderate easterly low level flow across our area to the south of the Atlantic ridge. With ample moisture available, convection will be possible anytime but perhaps favoring the night and morning hours. Have maintained 40 percent PoPs from Saturday through Tuesday. && .MARINE... Issued at 423 AM EDT Wed Jun 26 2024 Overnight observations show SW/W breezes of 5 to 10 knots along the reef and at Long Key C-MAN, with seas at Satan Shoal running below 1 foot. Conditions will be favorable for cloud lines and waterspouts across the nearshore waters around the Keys island chain once again today. From the synopsis, a weak ridge axis will extend westward from the western Atlantic across the Straits of Florida today through Thursday morning, with light to gentle southwest to west breezes prevailing over the Keys waters. Breezes may become variable at times during this period. The ridge will shift back northward Thursday afternoon through Friday, allowing light southeast breezes to resume. Building high pressure over the western Atlantic during the weekend will bring gentle to moderate easterly breezes across the Keys waters. && .AVIATION... (06Z TAFS) Issued at 423 AM EDT Wed Jun 26 2024 VFR conditions persist at EYW and MTH today. Light near surface winds will remain westerly to southwesterly, indicating potential cloud lines across the Middle and Lower Keys. TEMPOs will be issued if showers develop near the island terminals. && .CLIMATE... On this day in 2020, a daily record warm low temperature of 86F was measured in Key West. This measurement tied for the warmest low temperature ever recorded in June. Temperature records for Key West date back to 1873. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...Jacobson Aviation/Nowcasts....AJP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest