859
FXUS62 KKEY 051520
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1120 AM EDT SAT SEP 5 2026
..NEW DISCUSSION, MARINE, 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.
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.
AVIATION
(15Z TAFS)
ISSUED AT 1105 AM EDT SAT SEP 5 2026
WHILE VFR CONDITIONS WILL PREVAIL AT BOTH EYW AND MTH THROUGH 12
SUNDAY MORNING, DEEP TROPICAL MOISTURE WILL SUPPORT SCATTERED
SHOWERS AND THUNDERSTORMS THAT COULD PASS OVER BOTH TERMINALS AT
TIMES, PARTICULARLY EARLY IN THE TAF PERIOD, RESULTING IN LOW
CEILINGS AND VISIBILITIES. A GENERAL MENTION OF VCSH IS INCLUDED
IN THE TAFS FOR NOW, ALTHOUGH THIS WILL BE REEVALUATED FOR THE 18Z
STANDARD TAF ISSUANCE.
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...BT
AVIATION/NOWCASTS....BT
DATA ACQUISITION.....BT
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