813  
FXUS62 KKEY 081917  
AFDKEY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE KEY WEST FL  
317 PM EDT TUE JUL 8 2025  
   
..NEW AVIATION
 
 
   
AVIATION
 
 
(18Z TAFS)  
ISSUED AT 306 PM EDT TUE JUL 8 2025  
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH EYW AND MTH FOR THE  
REST OF TODAY AND INTO TONIGHT. WHILE A FEW CLOUDLINES HAVE  
ATTEMPTED TO FORM IN THE VICINITY OF THE ISLAND CHAIN, NONE HAVE  
DEVELOPED IN SUCH A WAY THAT IMPACTS EITHER TERMINAL YET.  
MEANWHILE, A CLUSTER OF THUNDERSTORMS MOVING SOUTHWEST OFF OF  
SOUTH FLORIDA POSES SOMEWHAT OF A THREAT TO THE LOWER KEYS IF IT  
HOLDS TOGETHER OVER THE NEXT FEW HOURS, BUT LOW CONFIDENCE IN IT  
SURVIVING THE TRIP WILL KEEP MENTION OUT OF THE TAFS FOR NOW.  
SHORT TERM AMENDMENTS WILL COVER ANY UNEXPECTED DEVELOPMENTS  
RELATING TO REIGNITING CLOUD LINES AND THE PREVIOUSLY MENTIONED  
THUNDERSTORM CLUSTER. NEAR SURFACE WINDS WILL BE OUT OF THE  
NORTHEAST AT 5 TO 10 KNOTS, WITH OCCASIONAL HIGHER GUSTS NEAR 15  
KNOTS AT EYW EARLY.  
 

 
   
PREVIOUS DISCUSSION
 
 
ISSUED AT 1120 AM EDT TUE JUL 8 2025  
ANOTHER SUMMER DAY IS UNDERWAY ACROSS THE FLORIDA KEYS. KBYX RADAR  
DETECTS A FEW SHOWERS WITH A THUNDERSTORM HERE AND THERE BUBBLING  
ALONG OLD OUTFLOW BOUNDARIES IN THE STRAITS OF FLORIDA AND IN THE  
GULF WATERS WEST OF THE LOWER KEYS. MEANWHILE, GOES-19 VISIBLE  
IMAGERY NOTES CUMULUS CLOUD STREAMERS PROPAGATING SOUTHWEST OFF OF  
THE MIDDLE KEYS WITH NOT MUCH ELSE OVER THE ISLAND CHAIN. THIS HAS  
ALLOWED FOR A WARM START TO TODAY WITH TEMPERATURES ON LAND ALREADY  
READING IN THE MID TO UPPER 80S. MODERATE NORTHEAST TO EAST WINDS  
PREVAIL ALONG THE REEF AND UP INTO SOUTH FLORIDA WITH A MAINLAND  
SHADOW KEEPING SKIES CLEAR IN OUR GULF WATERS JUST OFF OF  
FLORIDA'S WEST COAST. OVERALL, BREEZES ARE SLIGHTLY HIGHER THAN  
YESTERDAY WHILE SHOWER COVERAGE HAS SHIFTED MORE TO OUR SOUTHERN  
WATERS.  
 
THE SHORT TERM FORECAST FINDS US IN A BIT OF A LULL REGARDING RAIN  
CHANCES. NORMALLY, A TYPICAL SUMMER DAY WITH GENTLE TO MODERATE  
NORTHEAST BREEZES AND AVERAGE MOISTURE CONTENT WOULD POINT US  
TOWARDS CLOUDLINES FORMING ALONG THE ISLAND CHAIN. WHILE THIS  
ISN'T ENTIRELY OUT OF THE QUESTION, THERE ARE A FEW FACTORS  
WORKING AGAINST IT TODAY. WHILE THIS MORNING'S KKEY SOUNDING DID  
OBSERVE A NEAR NORMAL PW VALUE (~1.8 INCHES), CIMSS MIMIC TPW  
DEPICTS A SWATH OF RELATIVELY DRY AIR (PW OF ~1.6 INCHES) OVER  
THE KEYS BETWEEN A SLUG OF TROPICAL MOISTURE IN THE GULF AND  
MOISTURE ASSOCIATED WITH THE INCOMING INVERTED TROUGH CHURNING  
THROUGH THE EAST END OF THE BAHAMAS. FURTHERMORE, DRY AIR OBSERVED  
JUST ABOVE THE INVERSION AT 900 MB MAY ALSO BE ENTRAINING INTO  
POCKETS OF DEVELOPING CONVECTION MAKING ANY DEEP DEVELOPMENT SHORT  
LIVED AT BEST. FINALLY, BREEZES ARE A TOUCH HIGHER THAN THE USUAL  
NEARLY STATIONARY CLOUDLINE LIKES TO LIVE IN. DESPITE ALL OF THESE  
FACTORS WORKING AGAINST RAINFALL, WE STILL ARE OPTING TO SIT ON  
THE HIGHER SIDE OF GUIDANCE WITH SLIGHT RAIN CHANCES JUST BELOW  
NORMAL FOR THIS TIME OF YEAR. AS THE PREVIOUSLY MENTIONED INVERTED  
TROUGH CONTINUES TO SHIFT WEST, RAIN CHANCES WILL GRADUALLY  
INCREASE THROUGH TONIGHT AND INTO TOMORROW.  
 

 
   
FORECAST
 
 
ISSUED AT 452 AM EDT TUE JUL 8 2025  
CIMSS ANALYSIS PRODUCTS HAVE BEEN VERY HELPFUL WHEN IT HAS COME TO  
TRYING TO SORT THIS PATTERN OUT. MIMIC LAYER PWAT SHOWS THAT  
COMPARATIVELY DRIER AIR WILL PREVAIL FOR AT LEAST TODAY, BUT AN  
AREA OF ENHANCED MOISTURE EXISTS OVER THE BAHAMAS AND EASTERN  
CUBA. VORTICITY ANALYSIS SHOWS AN ELONGATED AREA OF RELATIVE  
VORTICITY AT THE 200 MB LEVEL OVERHEAD, BUT THIS FEATURE IS LOST  
AS WE PROGRESS DOWNWARD THROUGH THE ATMOSPHERE, AND IS LIKELY  
PLAYING A ROLE IN OUR QUIETER RADAR. HOWEVER, AT THE 500MB AND  
700MB LEVELS, WE CAN SEE TWO AREAS OF INTEREST OVER THE BAHAMAS,  
AND TO THE SOUTH OF CUBA. WITH THE DEEP LAYER STEERING FLOW  
LOOKING A LITTLE KINKY, IT IS HARD TO SAY WHICH ONCE OF THESE  
AREAS IS GOING TO POSSIBLY RESULT IN SOME ACTIVE WEATHER. GLOBAL  
DETERMINISTIC AND ENSEMBLE GUIDANCE ARE STILL INDICATING THAT ONE  
OF THESE AREAS OF CYCLONIC FLOW WILL PUSH ACROSS THE AREA  
WEDNESDAY NIGHT AND THURSDAY, BRINGING AN UPTICK IN MOISTURE AND  
AN INCREASE IN POPS. FOR NOW, WE WILL CONTINUE TO ADVERTISE POPS  
BETWEEN 30 AND 40 PERCENT FROM WEDNESDAY ONWARD, WITH A PEAK OF 50  
PERCENT POPS ON THURSDAY. THE UNCERTAINTY MAINLY STEMS FROM  
GUIDANCE STRUGGLING TO REFLECT THIS WAVE AT THE SURFACE, BUT THERE  
ARE SOME HINTS OF AN INVERTED TROUGH IN THE LOWER LEVELS OF THE  
ATMOSPHERE.  
 

 
 
   
MARINE
 
 
ISSUED AT 1120 AM EDT TUE JUL 8 2025  
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR  
THE COASTAL WATERS OF THE FLORIDA KEY. FROM SYNOPSIS, A BUILDING  
ATLANTIC HIGH WILL SUSTAIN GENTLE TO MODERATE BREEZES FOR THE NEXT  
FEW DAYS. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CLOSE TO  
NORMAL THROUGH WEDNESDAY, BUT AN EASTERLY WAVE AND VEERING WINDS  
MAY GENERATE ELEVATED SHOWER COVERAGE FROM WEDNESDAY EVENING  
THROUGH THE END OF THE WEEK.  
 

 
   
CLIMATE
 
 
ON THIS DAY IN 2023, THE DAILY RECORD HIGH TEMPERATURE OF 97F WAS  
RECORDED AT MARATHON. TEMPERATURE RECORDS FOR MARATHON DATE BACK TO  
1950.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
KEY WEST 81 91 81 91 / 20 30 40 50  
MARATHON 81 89 81 89 / 20 30 40 50  
 

 
   
KEY WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
GM...NONE.  

 
 

 
 
PUBLIC/MARINE/FIRE...JAM  
AVIATION/NOWCASTS....JAM  
DATA ACQUISITION.....JAM  
 
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