000  
FXUS62 KKEY 051800  
AFDKEY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE KEY WEST FL  
200 PM EDT SAT SEP 5 2026  
   
..NEW DISCUSSION, AVIATION  
 
   
KEY MESSAGES  
 
- A MOISTURE SURGE WILL SUPPORT BOUTS OF ELEVATED RAIN AND  
THUNDER CHANCES THROUGH THE LABOR DAY HOLIDAY WEEKEND.  
 
- THE PRIMARY THREAT FOR ANY STRONGER THUNDERSTORMS WILL BE  
DANGEROUS LIGHTNING STRIKES. WHEN THUNDER ROARS, GO INDOORS. IF  
ON A BOAT, STAY LOW, OR GO BELOW.  
 
- HEAT INDICES WILL APPROACH THE MID 100S DAILY, WITH LITTLE  
RELIEF IN THE MUGGY CONDITIONS OVERNIGHT. KNOW THE SIGNS OF  
HEAT STRESS, TAKE FREQUENT BREAKS, AND STAY HYDRATED.  
 
 
   
AVIATION  
 
(18Z TAFS)  
ISSUED AT 155 PM EDT SAT SEP 5 2026  
VFR CONDITIONS WILL PREVAIL THROUGH MOST OF THE EVENING HOURS. A  
WAVE OF MODESTLY DRIER AIR SHOULD SUPPRESS MOST VICINITY SHOWERS  
THROUGH AT LEAST 06Z THIS EVENING. THEREAFTER, ADDITIONAL ACTIVITY  
MAY DEVELOP. CONFIDENCE IS TOO LOW TO INCLUDE EXPLICIT MENTION OF  
POTENTIAL IMPACTS TO THE TERMINALS AT THIS TIME, ALTHOUGH THIS  
WILL BE REEVALUATED FOR THE 00Z TAF ISSUANCE. NEAR-SURFACE WINDS  
WILL GO VARIABLE THIS EVENING, GRADUALLY RESUMING A SOUTHEASTERLY  
DIRECT OVERNIGHT THROUGH 18Z SUNDAY.  
 
 
   
PREV DISCUSSION  
 
ISSUED AT 1105 AM EDT SAT SEP 5 2026  
LOW-LEVEL GEOPOTENTIAL HEIGHT AND WIND ANALYSIS DEPICTS A  
DEPARTING INVERTED TROUGH APPROACHING THE CENTRAL GULF, A SECOND  
INVERTED TROUGH APPROACHING THE EASTERN BAHAMAS, AND A SURFACE  
HIGH PRESSURE SYSTEM EXTENDING ACROSS MUCH OF THE NORTH ATLANTIC.  
THE SUM OF THESE FEATURES SUPPORTS GENERALLY LIGHT SOUTHEAST TO  
SOUTH SURFACE WINDS. THE 12Z MORNING SOUNDING SAMPLED AT KEY  
HIGHLIGHTED DEEP TROPICAL MOISTURE, ALONG WITH UNIDIRECTIONAL  
SOUTHEASTERLY MEAN STEERING FLOW AT AROUND 10 KNOTS. KBYX RADAR  
HAS BEEN FAIRLY ACTIVE ALL MORNING, DEPICTING SCATTERED SHOWERS  
WITH A FEW SPECKLED EMBEDDED THUNDERSTORMS, MAINLY ACROSS THE  
LOWER KEYS AND TO THE NORTHWEST. THIS IS WHERE CIMSS TOTAL  
PRECIPITABLE WATER PRODUCT HIGHLIGHTS THE BEST TROPOSPHERIC-  
INTEGRATED MOISTURE, LARGELY ASSOCIATED WITH THE EASTERN FLANK OF  
THE AFOREMENTIONED DEPARTING EASTERLY WAVE.  
 
FOR THE BALANCE OF TODAY, EXPECTING THE HEAVIEST CONVECTIVE  
ACTIVITY TO BE WITHIN THE NEXT SEVERAL HOURS, BEFORE AN UNDULATION  
OF DRIER AIR WORKS TOWARDS THE CWA. THE WAVE OF DRIER AIR WILL BE  
SHORT-LIVED, WITH A BATCH OF MOIST AIR TRAILING THIS FEATURE  
ACROSS THE BAHAMAS, MAKING ITS WAY TO THE KEYS LATE TONIGHT  
THROUGH SUNDAY. THE INHERITED FORECAST CALLS FOR MID- LEVEL RAIN  
AND THUNDER CHANCES TODAY, AND GIVEN RADAR TRENDS, THIS SEEMS  
QUITE PLAUSIBLE, MAINLY ACROSS THE LOWER AND MIDDLE KEYS. NO  
CHANGES PROPOSED.  
 
 
   
MARINE  
 
ISSUED AT 1105 AM EDT SAT SEP 5 2026  
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR  
THE FLORIDA KEYS. FROM SYNOPSIS, LIGHT TO GENTLE SOUTHEAST BREEZES  
WILL PREVAIL THROUGH MID WEEK AS WEAK STEERING FLOW PERSISTS  
ACROSS THE REGION, THEREAFTER BREEZES WILL FRESHEN TO GENTLE TO  
MODERATE AS HIGH PRESSURE BUILDS IN. WAVES OF LOW- LEVEL MOISTURE  
PUSHING ACROSS THE KEYS WILL SUPPORT ELEVATED RAIN AND THUNDER  
CHANCES THROUGH SUNDAY, POSSIBLY RETURNING TO NEAR NORMAL BY MID  
WEEK.  
 
 
   
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  
 
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WWW.FACEBOOK.COM/NWSKEYWEST  
WWW.X.COM/NWSKEYWEST  
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