230
FXUS62 KKEY 141434
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1034 AM EDT FRI AUG 14 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- A COASTAL FLOOD STATEMENT REMAINS IN EFFECT FOR THE LOWER AND
MIDDLE KEYS, WITH MINOR SALTWATER FLOODING POSSIBLE, ESPECIALLY
AROUND THE TIME OF HIGH TIDE.
- EXPECT ELEVATED RAIN AND THUNDER CHANCES FOR THIS AFTERNOON
THROUGH SATURDAY EVENING.
- A SWATH OF SAHARAN DRY AIR WILL PUSH ACROSS THE KEYS FOR THE
SECOND HALF OF THE WEEKEND, LASTING THROUGH EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 1033 AM EDT FRI AUG 14 2026
CIMSS MIMIC TOTAL PRECIPITABLE WATER (TPW) SHOWS A RATHER LARGE
PLUME OF INCREASED MOISTURE SURGING NORTHWEST TOWARDS THE FLORIDA
KEYS THIS MORNING. THE DEEPEST MOISTURE WITH THIS SURGE IS STILL
TO THE SOUTH OF ANDROS ISLAND, BUT IT IS RAPIDLY PRESSING
NORTHWESTWARD. BEHIND THIS SURGE OF MOISTURE, WE CAN ALSO SEE
QUITE DRY AIR PRESSING WESTWARD. THIS DRY AIR WAS CURRENTLY OVER
AND TO THE NORTH OF HISPANIOLA AND PUERTO RICO. KBYX RADAR IS
ACTIVE THIS MORNING WITH SHOWERS AND THUNDERSTORMS BEING DETECTED
MAINLY ACROSS THE STRAITS OF FLORIDA AND THE SE GULF WATERS TO THE
SOUTHEAST TO T TOWER. TEMPERATURES ALONG THE ISLAND CHAIN ARE IN
THE UPPER 80S TO NEAR 90 DEGREES AND DEW POINTS ARE IN THE MID TO
UPPER 70S. CIMSS PRODUCTS ALSO CONTINUE TO SHOW A MEAN LAYER RIDGE
ACROSS THE CENTRAL NORTH ATLANTIC. THE WESTERN PERIPHERY OF THIS
RIDGE EXTENDS WESTWARD INTO THE KEYS THIS MORNING. MARINE
OBSERVATION PLATFORMS SURROUNDING THE ISLAND CHAIN ARE OBSERVING
EAST TO SOUTHEAST BREEZES NEAR 10 KNOTS AS A RESULT.
SHORT TERM FORECAST
THE 12Z MORNING SOUNDING SHOWS A FAIRLY MOIST PROFILE THROUGH THE
LOWEST SEVERAL THOUSAND FEET ALONG WITH ANOTHER LAYER FROM
APPROXIMATELY 600-400 MB. THERE WAS ALSO A DECENT AMOUNT OF DRY
AIR BETWEEN 850 TO 600 MB. INSTABILITY ISN'T CRAZY BUT IT IS STILL
QUITE HIGH WITH CAPE VALUES BETWEEN 2200-2600 J/KG. THE PWAT VALUE
MEASURED IS A LITTLE BIT LOWER THAN YESTERDAY AT 1.71 INCHES.
THIS IS CLOSE TO THE 25TH PERCENTILE FOR THE DATE. THE WIND
PROFILE IS PROBABLY THE BIGGEST CHANGE FROM YESTERDAY WITH MAINLY
EAST TO SOUTHEAST BREEZES BUT WITH SPEEDS NEAR 15 KNOTS. OVERALL,
NO CHANGES EXPECTED TO THE ONGOING FORECAST OF 30% FOR TODAY AS
THE DRY AIR LAYER IS A LITTLE CONCERNING FOR SOME OF THE SHOWER
ACTIVITY AS IT APPROACHES THE ISLAND CHAIN. SOME OF THE SHOWERS
MAY ENTRAIN THIS DRY AIR THUS WEAKENING THEM OR EVEN CHOKING THEM
OFF COMPLETELY. THE BETTER CHANCE FOR SHOWER ACTIVITY APPEARS TO
BE OVERNIGHT AND INTO SATURDAY MORNING WHEN THE DEEPEST MOISTURE
NEAR ANDROS ISLAND WILL BASICALLY BE OVERHEAD.
PREV DISCUSSION
ISSUED AT 400 AM EDT FRI AUG 14 2026
SURFACE WIND AND PRESSURE ANALYSIS PLACES AN EXPANSIVE HIGH
PRESSURE SYSTEM CENTERED IN THE VICINITY OF THE AZORES IN THE
NORTH ATLANTIC, WHICH CONTINUES TO STRENGTHEN AND BUILD WESTWARD.
THE AXIS OF THE RIDGE IS BISECTING THE FLORIDA SPACE COAST.
MEANWHILE, LOWER TROPOSPHERIC VORTICITY ANALYSIS PLACES AN
INVERTED TROUGH IN THE VICINITY OF EASTERN CUBA AND THE ISLAND OF
HISPANIOLA. FINALLY, SATELLITE-DERIVED LAYER- AND ATMOSPHERIC-
INTEGRATED PRECIPITABLE WATER PRODUCTS ARE HIGHLIGHTING A
POSTIVELY-TILTED, DISCERNIBLE MOISTURE SURGE EXTENDING FROM ANDROS
ISLAND NORTHEASTWARD TO THE CENTRAL BAHAMAS. LOCALLY, EARLIER
CONVECTION ASSOCIATED WITH A BROKEN CLOUD LINE OVER PORTIONS OF
THE LOWER KEYS HAS SINCE WANED, WITH LOCAL KBYX DOPPLER RADAR NOW
ONLY DETECTING ISOLATED SHOWERS ACROSS THE KEYS MARINE ZONES.
LAND- BASED SURFACE OBSERVATIONS ARE SAMPLING TEMPERATURES IN THE
BALMY MID 80S AT THIS EARLY FRIDAY MORNING HOUR.
OVERALL, WITH A NOTICEABLE INCREASE IN FORCING AND STEERING FLOW,
THE FLORIDA KEYS WILL QUICKLY MOVE FROM A MESOSCALE REGIME TO A
SYNOPTIC-SCALE FORCED REGIME LATER TODAY THROUGH THE WEEKEND. THE
AFOREMENTIONED MOISTURE SURGE, COINCIDENT WITH THE INVERTED
TROUGH TO ITS SOUTHWEST, WILL PROGRESS WESTWARD TODAY. MEANWHILE,
AT THE SURFACE, THE HIGH PRESSURE SYSTEM WILL CONTINUE TO BUILD
WESTWARD TOWARDS THE FLORIDA PENINSULA, SUPPORTING FRESHENING EAST
TO SOUTHEAST BREEZES. COMPOSTING THESE FEATURES WILL RESULT IN A
WETTER AND MORE THUNDERY PATTERN BEGINNING LATER THIS AFTERNOON,
CONTINUING THROUGH AT LEAST SATURDAY MORNING. FORECAST SOUNDINGS
DO INDICATE A BIT OF INHIBITION TO OVERCOME, WHICH WILL CONTINUED
TO BE MONITORED, AS IT MAY LIMIT MORE WIDESPREAD AND STRONGER
THUNDERSTORMS ACROSS THE KEYS FOR THESE PERIODS.
THEREAFTER, THERE IS HIGH CONFIDENCE THAT A STRONG SAHARAN DUST
LAYER (A BIT UNUSUAL FOR THIS LATE IN AUGUST) WILL PROPAGATE
WESTWARD TOWARDS THE KEYS BY SOMETIME LATE SATURDAY AFTERNOON OR
EARLY SUNDAY EVENING. WHILE THIS WILL TEND TO SHUT DOWN ANY SHOWER
AND THUNDERSTORM ACTIVITY THEREAFTER FOR SEVERAL DAYS, WE WILL
NEED TO MONITOR THE LEADING EDGE OF THIS DUST PLUME. THE LEADING
EDGE IS ANALOGOUS TO A CLASSIC MID-WEST DRY LINE, WITH A
DISCERNIBLE LINE OF DEEP CONVECTIVE THUNDERSTORMS OFTEN OCCURRING
AS THE PLUME PUSHES THROUGH THE KEYS.
IN TERMS OF THE TROPICS, ALTHOUGH THE NATIONAL HURRICANE CENTER IS
MONITORING TWO POSSIBLE AREAS IN THE MAIN DEVELOPMENT REGION OF
THE TROPICAL ATLANTIC, CHANCES FOR DEVELOPMENT OF BOTH SYSTEMS
CONTINUES TO WANE. REGARDLESS OF DEVELOPMENT, NEITHER SYSTEM IS
EXPECTED TO PROVIDE IMPACTS TO THE KEYS AT THIS TIME.
MARINE
ISSUED AT 1033 AM EDT FRI AUG 14 2026
A COASTAL FLOOD STATEMENT REMAINS IN EFFECT FOR THE LOWER AND
MIDDLE KEYS THROUGH LATE AFTERNOON. FROM SYNOPSIS, HIGH PRESSURE
IN THE CENTRAL NORTH ATLANTIC WILL STRENGTHEN AND BUILD WESTWARD
FOR THE NEXT SEVERAL DAYS. WITH THE ASSOCIATED RIDGE AXIS LOCATED
NORTH OF THE FLORIDA KEYS, THIS WILL SUPPORT GENTLE TO MODERATE
EAST TO SOUTHEAST BREEZES FOR THE MARINE ZONES THROUGH SUNDAY
NIGHT. A WEAK FRONTAL BOUNDARY WILL STALL OVER THE FLORIDA
PENINSULA FOR EARLY NEXT WEEK. THIS WILL DISRUPT THE RIDGE'S
INFLUENCE ON THE KEYS COASTAL WATERS. BREEZES WILL RESPOND,
BECOMING LIGHT TO GENTLE.
AVIATION
(15Z TAFS)
ISSUED AT 1033 AM EDT FRI AUG 14 2026
VFR CONDITIONS ARE MAINLY EXPECTED TO PERSIST THROUGH THE TAF
PERIOD AT BOTH EYW AND MTH TERMINALS. HOWEVER, A SURGE OF TROPICAL
MOISTURE IS ANTICIPATED TO MOVE ITS WAY THROUGH THE FLORIDA KEYS
THIS AFTERNOON CONTINUING THROUGH SATURDAY EVENING. BASICALLY,
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THIS
PERIOD WITH THE BEST CHANCE SEEMING TO BE OVERNIGHT THROUGH
SATURDAY MORNING. THOUGH, WE CANNOT RULE OUT ACTIVITY OUTSIDE OF
THAT TIME FRAME AS WELL. THEREFORE, VCSH WAS INCLUDED IN THE TAF
WITH 14/21Z FOR MTH AND 15/00Z FOR EYW. ANY SHOWERS AND STORMS
WILL BE CAPABLE OF REDUCING CIGS WITH THE POTENTIAL FOR VIS TO
MVFR AS WELL. THERE IS ALSO THE LOW RISK/PROBABILITY FOR IFR. IN
ADDITION, GUSTY WINDS ARE POSSIBLE ALONG WITH CLOUD TO GROUND
LIGHTNING STRIKES. OTHERWISE, NEAR SURFACE WINDS WILL REMAIN
MOSTLY EAST TO SOUTHEAST THROUGH THE PERIOD WITH ANOTHER PERIOD OF
NORTHEAST TO EAST LATE THIS AFTERNOON INTO THIS EVENING.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 91 81 91 82 / 20 50 40 10
MARATHON 89 82 89 83 / 30 50 40 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...MJV
AVIATION/NOWCASTS....MJV
DATA ACQUISITION.....MJV
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