Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
479 FXUS62 KKEY 191928 AFDKEY Area Forecast Discussion National Weather Service Key West FL 328 PM EDT Sun Jul 19 2026 ...New DISCUSSION, MARINE, AVIATION, PREV DISCUSSION... .KEY MESSAGES... - Gentle to moderate southeast to south breezes are expected across Florida Keys coastal waters for the next few days peaking overnight and lulling during the day. - Heat indices may approach 108 to 110 degrees each afternoon for some Florida Keys island communities. - Saharan Air Layer plumes will transit the area over the next several days, limiting rain and thunder chances. && .DISCUSSION... Issued at 1148 AM EDT Sun Jul 19 2026 An upper-level composite analysis this morning reveals newly formed Tropical Depression Two over the northeastern Gulf of America, with deep-layer mean anticyclones positioned to its east and west. The Florida Keys lie within the deep southerly flow between the deep-layer mean cyclonic circulation containing the new depression and the anticyclone centered over the subtropical Atlantic east of the Bahamas. Data from the Key West morning radiosonde balloon indicated a very moist and unstable thermodynamic stratification with near nil convective inhibition. However, at the moment, Key West Doppler radar scans are nearly void of precipitation echoes over the service area. The balloon- derived data likely is more representative of the atmosphere over the Gulf waters just north of the lower Keys as satellite-derived total precipitable water measurements suggest much drier air upstream over the Straits of Florida and Cuba. This factor combined with a lack of mechanisms to initiate deep convection would explain the dearth of cumulus convection observed this morning. Current air temperatures in most Keys island communities are in the upper 80s, with dewpoint temperatures in the upper 70s yielding heat indices of 100-105F. Steady southerly breezes prevail in most areas. && .MARINE... Issued at 1148 AM EDT Sun Jul 19 2026 No watches, warnings, or advisories are in effect across Florida Keys coastal waters. At 11:00 a.m. EDT, newly formed Tropical Depression Two was centered over the northeastern Gulf of America, about 280 nautical miles northwest of Key West Harbor, moving north- northwestward at 2 knots. Tropical Depression Two is expected to move slowly northwestward or north-northwestward during the next day or two, followed by a turn toward the west. On the forecast track, the depression will move near or along the northern Gulf coast during the next several days. An Atlantic ridge of high pressure will extend to the Florida Peninsula for the next several days. Gentle to moderate south to southeasterly breezes are expected to prevail across Florida Keys coastal waters from this afternoon through Thursday. && .AVIATION... (18Z TAFS) Issued at 328 PM EDT Sun Jul 19 2026 Through 20/18Z, prevailing VFR conditions are expected at both EYW and MTH. A north-south line of broken showers has developed 10-15 miles west of MTH, and will possibly transition into the vicinity; hence, VCSH at MTH through 19/21Z. Otherwise, the potential for any transient showers or storms and associated sub- VFR conditions remains at the terminals remains too slim for mention in the TAFs. Surface winds did shift out of the SSW (220 degrees) at EYW within the last few hours. However, winds should shift back slower to 170-180 degrees by 20/00Z. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...Kasper Aviation/Nowcasts....Kasper Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest