104  
FXUS62 KKEY 091523  
AFDKEY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE KEY WEST FL  
1123 AM EDT WED JUL 9 2025  
   
..NEW DISCUSSION, MARINE, AVIATION  
 
   
DISCUSSION  
 
ISSUED AT 1100 AM EDT WED JUL 9 2025  
SURFACE ANALYSIS DEPICTS AN EXPANSIVE AREA OF SURFACE HIGH  
PRESSURE ACROSS THE NORTH ATLANTIC. LOW- AND MID-LEVEL VORTICITY  
ANALYSIS PLACES A POSITIVELY TILTED INVERTED TROUGH EXTENDING FROM  
THE WESTERN BAHAMAS SOUTHWESTWARD TOWARDS THE WESTERN CARIBBEAN  
SOUTH OF CUBA. THE 12Z MORNING SOUNDING AT KEY SUPPORTS THIS  
FEATURE, WITH MODESTLY FALLING GEOPOTENTIAL HEIGHTS BETWEEN  
900-500 MB. THE SOUNDING ALSO DEPICTED SIGNIFICANT DRY AIR BETWEEN  
800-500 MB, ALTHOUGH RECENT SATELLITE-DERIVED MOISTURE  
OBSERVATIONS SUGGEST A WELL-DEFINED SLEW OF MOISTURE IS QUICKLY  
APPROACHING THE KEYS. ASSOCIATED WITH THE MOISTURE SURGE, KBYX  
DOPPLER RADAR HAS BEEN DETECTING SCATTERED SHOWERS WITH ISOLATED,  
BRIEFLY STRONGER EMBEDDED THUNDERSTORMS ACROSS THE COASTAL WATERS  
MAINLY SOUTH OF THE ISLAND CHAIN. OUTSIDE OF THE UPPER KEYS, MOST  
ISLAND COMMUNITIES HAVE REMAINED DRY SO FAR TODAY.  
 
FOR THE BALANCE OF THIS AFTERNOON, SHOWER AND THUNDERSTORM  
ACTIVITY SHOULD GRADUALLY WANE OVER THE NEXT COUPLE HOURS ACROSS  
THE STRAITS AND THE MIDDLE AND UPPER KEYS. AVAILABLE CONVECTIVE  
ALLOWING MODEL (CAM) GUIDANCE, INCLUDING OUR OFTEN REFERENCED HRRR  
MODEL, SUPPORTS THIS EVOLUTION. VISIBLE SATELLITE OBSERVATIONS  
DEPICT A WELL- DEFINED CIRRUS DECK STREAMING NORTHEASTWARD TOWARDS  
THE LOWER KEYS AWAY FROM THE CONVECTION IN THE STRAITS. THIS MAY  
LIMIT (OR AT LEAST DELAY) WHAT WOULD NORMALLY BE A FAVORABLE  
ENVIRONMENT FOR A LOWER KEYS ISLAND CLOUD LINE EVENT. THE IN-HOUSE  
WATERSPOUT INDEX BASED ON THE MORNING KEY SOUNDING WAS WELL ABOVE  
CLIMATOLOGY, SUPPORTIVE OF THE POSSIBLE ISLAND CLOUD LINE  
FORMATION AND ASSOCIATED WATERSPOUT OUTBREAKS. WEIGHING IN ALL OF  
THIS, ELECTED TO PUNT ANY CHANGES TO THE INHERITED ONCE-PER-DAY  
FULL FORECAST PACKAGE.  
 
 
   
MARINE  
 
ISSUED AT 1100 AM EDT WED JUL 9 2025  
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT IN THE  
FLORIDA KEYS WATERS. FROM SYNOPSIS, A NORTH ATLANTIC AREA OF  
SURFACE HIGH PRESSURE WILL MAINTAIN GENTLE TO MODERATE BREEZES  
EASTERLY ACROSS THE FLORIDA KEYS THROUGH THIS AFTERNOON. AN  
EASTERLY TROPICAL WAVE WILL CONTINUE TO APPROACH THE KEYS THIS  
AFTERNOON AND TONIGHT. IN CONJUNCTION WITH VEERING WINDS, SHOWER  
AND THUNDER COVERAGE WILL BECOME ELEVATED TONIGHT, LASTING THROUGH  
THE END OF THE WORK WEEK. A RETURN TO NEAR-NORMAL RAIN AND  
THUNDER CHANCES IS EXPECTED FOR NEXT WEEKEND.  
 
 
   
AVIATION  
 
(15Z TAFS)  
ISSUED AT 1100 AM EDT WED JUL 9 2025  
WHILE VFR CONDITIONS WILL PREVAIL AT BOTH ISLAND TERMINALS THROUGH  
12Z THURSDAY MORNING, A SURGE OF MOISTURE WILL SUPPORT VICINITY  
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS LATE THIS MORNING  
THROUGH THE EARLY AFTERNOON AT MTH. THEREAFTER, AN ISLAND CLOUD  
LINE MAY FORM IN THE VICINITY OF EYW LATER THIS AFTERNOON,  
SUPPORTING ANOTHER ROUND OF NEARBY SHOWERS AND POSSIBLE  
THUNDERSTORMS. HAVE INCLUDED WINDOWS OF VCSH IN THE TAFS FOR NOW,  
GIVEN THE UNCERTAINTY IN COVERAGE AND EVOLUTION, WITH POSSIBLE  
SUB-VFR IMPACTS AT THE TERMINALS TO BE LEFT FOR POSSIBLE LATER TAF  
AMENDMENTS THIS AFTERNOON.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
KEY WEST 91 82 91 82 / 30 30 50 40  
MARATHON 89 81 89 82 / 40 30 50 50  
 
 
   
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  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab FL Page
Main Text Page