Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
542 FXUS62 KKEY 170749 AFDKEY Area Forecast Discussion National Weather Service Key West FL 349 AM EDT Sat Aug 17 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 349 AM EDT Sat Aug 17 2024 Southward movement of a weak moisture gradient over Florida and weak boundaries within the easterly steering flow will provide sources of lift across the Florida Keys today. CIMSS TPW and GOES- derived imagery measured PWAT values in excess of 2 inches over the island chain, supporting the 1.22 inches measured at KKEY and 1.82 inches at KMTH. Surface breezes and low level steering winds will remain gentle to light, so any small shower could generate surprising amounts of rainfall. Despite the above normal chances for showers, a Heat Advisory was issued due to dew points in the upper 70s to near 80, and sparse debris cloud cover as measured by GOES-East. While the subtropical ridge began to rebuild over the central United States and Mexico, both Hurricane Ernesto and a southward moving trough over the Eastern CONUS continue to keep the pressure gradient weak across Florida Keys waters. Showers and thunderstorms will be developing along mesoscale features, making the prediction of where and when showers will form extremely difficult despite the favorable environment. Expect heavy downpours and erratic winds near thunderstorms today and tonight. The aforementioned ridge will build through the weekend and allow development of a southwesterly steering flow, thus cloudline days, during the week. In the Atlantic, continued eastward movement of Hurricane Ernesto will allow the subtropical ridge to rebuild by midweek and hint at a shift towards southeasterly breezes by next Friday. A considerable amount remains unknown; a couple of questions are how deep will the trough over the East Coast become, at what point will the central CONUS ridge stop building, and where the subtropical ridge will rebuild across the western Atlantic. Regardless, weather over the week is likely going to be less active than this weekend. && .MARINE... Issued at 349 AM EDT Sat Aug 17 2024 There are no watches, warnings, or advisories in effect for the Florida Keys coastal waters. From synopsis, north to northeast light breezes persist across Florida Keys waters. Breezes will slacken from moderate to gentle to light to moderate during the day as a trough deepens over the eastern United States. Periods of variable breezes will veer southwesterly as large scale ridging rebuilds over the central United States. && .AVIATION... (06Z TAFS) Issued at 349 AM EDT Sat Aug 17 2024 VFR conditions will mostly prevail at both EYW and MTH through the TAF period. Higher rain chances are possible today and VCSH is included at both sites estimated to start around 13z. Thereafter, any direct impacts expected to either terminal will be included in a TEMPO if neccesary. Near surface winds will be easterly at 5 to 10 knots, outside of convection. && .CLIMATE... On this day in 1886, a Tropical Storm intensified into a Hurricane as it moved west northwest through the Straits about 50 miles south of Key West, where a minimum pressure of 29.68" was recorded, along with a peak wind of 48 and numerous gusts to 60 mph. A man was killed when a building collapsed on Duval st. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory from 10 AM this morning to 7 PM EDT this evening for FLZ076>078. GM...None. && $$ Public/Marine/Fire...AJP Aviation/Nowcasts....AP Data Acquisition.....AP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest