Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
464 FXUS62 KKEY 201430 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1030 AM EDT Sat Jul 20 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1030 AM EDT Sat Jul 20 2024 KBYX radar shows some isolated showers this morning moving to the west to northwest near 10 knots across the Keys. At times, a few sprinkles or a quick passing shower may move across the Chain but most of this activity was over the marine areas. GOES 16 Visible satellite imagery shows mainly cumulus and stratocumulus across the Keys moving from the southeast to northwest. Temperatures along the Island Chain are in the upper 80s to near 90 degrees with dew points in the upper 70s to near 80 degrees. The humidity combined with the actual air temperatures is making the heat indices (what it feels like out there) soar to between 105 to 110 degrees. Therefore, a Heat Advisory is in effect yet again today through 7 PM EDT this evening for heat index values up to 111 degrees. Deep mean layer ridging remain in place across much of the North Atlantic Ocean with the western periphery of this ridge extending westward through the Florida peninsula and into the central Gulf of Mexico. Therefore, marine platforms around the Keys are observing east to southeast breezes 10 to 15 knots with Island Chain communities observing 10 to 15 mph. .SHORT TERM FORECAST... The 12z morning sounding shows mainly a dry profile again, similar to yesterday. However, there is still a shallow moist layer present in the low levels between 975 mb and 950 mb. CAPE is very high with the sounding measuring 3625 J/kg indicating very high instability out there. PWAT measured is less than yesterday at this time coming in at 1.77 inches which is slightly below the median for the date of 1.83 inches. Wind profile is fairly consistent from the surface up to 800 mb with east to southeast flow. Suffice it to say, if we had any synoptic scale feature nearby that can really help to raise the air, we would be off to the races today in terms of thunderstorms. Taking a look north of Hispaniola this morning, the activity there is much more robust which is moving this way for later in the day Sunday continuing into Monday as the tropical wave passes through. For now, no changes needed to the ongoing forecast. && .MARINE... Issued at 1030 AM EDT Sat Jul 20 2024 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, atlantic ridging will remain across the Florida Peninsula through the weekend, with gentle to moderate east to southeast breezes continuing across the Keys coastal waters. A tropical wave is forecast to move through the area Sunday night and Monday, bringing an increase in rain and thunder chances. Gentle to moderate east to southeast breezes will resume behind the wave through the middle of next week, as the Atlantic ridge remains in place. && .AVIATION... (15Z TAFS) Issued at 1030 AM EDT Sat Jul 20 2024 Showers are quickly developing across the Straits of Florida and moving towards the island terminals. The heaviest activity looks to stay to the west of EYW though a stray shower cannot be ruled out. Therefore, have included a VCSH for both MTH and EYW through the next couple of hours. Thereafter, dry air should make quick work of any additional showers. Otherwise, VFR conditions will prevail with an east to southeast wind of 10 to 15 knots. && .CLIMATE... On this date in 1887, the daily low temperature of 70F was recorded in Key West. Temperature records for Key West date back to 1872. && .PRELIMINARY POINT TEMPS/POPS... Key West 92 84 91 81 / 30 20 50 60 Marathon 91 85 90 81 / 30 20 50 60 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory until 7 PM EDT this evening for FLZ076>078. GM...None. && $$ Public/Marine/Fire...MJV Aviation/Nowcasts....LIW Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest