733
FXUS62 KKEY 150804
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
404 AM EDT TUE SEP 15 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- NEAR TO SLIGHTLY-ABOVE NORMAL RAIN CHANCES IN THE SHORT TERM IS
EXPECTED TO GIVE WAY TO CONSIDERABLY HIGHER RAIN CHANCES LATER
IN THE WORK WEEK.
- WINDS ARE EXPECTED TO TREND UPWARDS OVER THE NEXT SEVERAL DAYS,
LIKELY PEAKING IN THE MODERATE TO FRESH RANGE AROUND MID WEEK.
- HEAT INDEX VALUES WILL RANGE FROM 100-108 DEGREES DAILY, WITH
LITTLE RELIEF FROM THE MUGGY CONDITIONS OVERNIGHT. KNOW THE
SIGNS OF HEAT STRESS, TAKE FREQUENT BREAKS, AND STAY HYDRATED.
DISCUSSION
ISSUED AT 400 AM EDT TUE SEP 15 2026
A WEAK SPLIT SURFACE RIDGE LINGERS ACROSS FLORIDA THIS MORNING.
AS A RESULT, SURFACE WINDS ARE LIGHT OUT OF THE EAST TO SOUTHEAST.
LAST EVENINGS SOUNDING INDICATED DEEP LAYERED MOISTURE REMAINS
QUITE HIGH WITH 2.19 INCHES OF PRECIPITABLE WATER. THIS WAS
SLIGHTLY ABOVE THE 90TH PERCENTILE FOR THE DATE. WHILE THERE WAS
AMPLE CAPE, WEAK INHIBITION AND WEAK FORCING HAS KEPT ACTIVITY
ISOLATED ACROSS THE AREA THROUGH MUCH OF THE NIGHT. MORE RECENTLY,
SCATTERED SHOWERS HAVE BEGUN PERCOLATING ACROSS OUR ZONES. ON THE
LARGER SCALE, A STRONG MID AND UPPER LEVEL RIDGE IS CURRENTLY
BUILDING ACROSS THE EASTERN UNITED STATES WHILE SHARP TROUGHING
IS DIGGING SOUTHWARD OFF THE ATLANTIC COAST.
OVER THE NEXT COUPLE OF DAYS, A ROBUST CONTINENTAL HIGH WILL
SPREAD SOUTH AND SOUTHWESTWARD THROUGH THE SOUTHEASTERN UNITED
STATES AND GRADUALLY BOLSTER THE LOCAL PRESSURE GRADIENT. EXPECT
LIGHT EAST TO SOUTHEASTERLY BREEZES TO FRESHEN MODESTLY LATER
THIS AFTERNOON AND EVENING OUT OF THE NORTHEAST TO EAST. DEEP
LAYERED MOISTURE IS EXPECTED TO SLIP SLIGHTLY THROUGH THE DAY WITH
WEAK LOWER LEVEL INHIBITION HOLDING ON. AS A RESULT, EXPECT NEAR
NORMAL SHOWER AND THUNDER CHANCES TODAY. ISLAND CLOUD LINES WILL
ONCE AGAIN BE POSSIBLE. TEMPERATURES WILL REMAIN TREND LESS WITH
HIGHS NEAR 90 AND LOWS IN THE LOWER 80S. DEW POINTS WILL HOLD IN
THE MID 70S.
THE TAIL END OF THE SHARP TROUGH DIGGING OFF THE ATLANTIC COAST
IS EXPECTED TO PINCH OFF AND INTERACT AND ABSORB A TUTT CELL
MOVING IN ACROSS HISPANIOLA AND THE CENTRAL BAHAMAS THROUGH THE
MIDDLE PORTION OF THE WEEK. AS A RESULT, DEEP LAYERED MOISTURE IS
EXPECTED TO INCREASE ACROSS AND EAST OF OUR AREA AS BROAD LOWER
LEVEL TROUGHING TAKES SHAPE. THE MID AND UPPER LEVEL LOW AND
LOWER LEVEL TROUGH IS EXPECTED TO SWEEP WESTWARD INTO OUR AREA
THROUGH THE BACK HALF OF THE WEEK. IN ADDITION, THE MID AND UPPER
LOW COMPLEX WILL RESULT IN FALLING HEIGHTS ALOFT. EXPECT SHOWER
AND THUNDER CHANCES TO TREND SHARPLY UPWARDS THROUGH THE MIDDLE OF
THE WEEK, LIKELY PEAKING IN THE THURSDAY TIME FRAME. BREEZES WILL
GRADUALLY RELAX AND VEER EAST TO SOUTHEAST AS THE TROUGH PUSHES
THROUGH.
IT MAY TAKE SOME TIME FOR THE COPIOUS ATMOSPHERIC MOISTURE TO
CLEAR OUT OF OUR AREA. THE TROUGH/LOW COMPLEX SHOULD SLOWLY
LUMBER WESTWARD INTO THE GULF WHILE BROAD RIDGING SETS UP OFF THE
ATLANTIC COAST. THIS WILL KEEP A BROAD MOIST CONFLUENT ZONE
ACROSS OUR AREA FOR QUITE SOME TIME. CONSEQUENTLY, A PROLONGED
PERIOD OF ABOVE NORMAL RAIN CHANCES ARE POSSIBLE THROUGH LATE WEEK
AND WEEKEND. WITH ALL THAT SAID, THE EVOLUTION OF THESE FEATURES
ARE HIGHLY UNCERTAIN AS IS OFTEN THE CASE WITH COMPLEX UPPER LEVEL
INTERACTIONS. THAT SAID, UNCERTAINTY IS HIGH AND MODEL TO MODEL
AND RUN TO RUN DISAGREEMENT IS HIGH.
MARINE
ISSUED AT 400 AM EDT TUE SEP 15 2026
WEAK AND SPLINTERED HIGH ACROSS FLORIDA WILL BE STEADILY
REINFORCED AND ULTIMATELY ABSORBED BY A STRONG CONTINENTAL HIGH
SPREADING SOUTHWARD THROUGH THE EASTERN UNITED STATES. LIGHT TO
GENTLE EASTERLY BREEZES WILL BEGIN FRESHENING LATER THIS AFTERNOON
AND EVENING OUT OF THE NORTHEAST TO EAST, BECOMING A MODERATE
BREEZE. WINDS ARE LIKELY TO PEAK THIS EVENING AND TOMORROW
EVENING. BROAD TROUGHING SET TO TAKE SHAPE OVER THE CENTRAL
BAHAMAS OVER THE NEXT SEVERAL DAYS WILL THEN MIGRATE WESTWARD
ACROSS THE KEYS REGION THROUGH THE BACK HALF OF THE WEEK. BREEZES
WILL SLACKEN AND STEADILY VEER EAST TO SOUTHEAST. ALONG WITH THIS
TROUGH, EXPECT INCREASING MOISTURE AND SHOWER AND THUNDER CHANCES
TO INCREASE SHARPLY AFTER MID WEEK AND FALL BACK TOWARDS NORMAL
HEADING INTO THE WEEKEND.
AVIATION
(00Z TAFS)
ISSUED AT 400 AM EDT TUE SEP 15 2026
VFR CONDITIONS WILL PREVAIL AT THE ISLAND TERMINALS TODAY. SHOWER
AND THUNDER CHANCES WILL BE NEAR NORMAL. SURFACE WINDS WILL BE
LIGHT TO GENTLE OUT OF THE EAST. WINDS ARE EXPECTED TO BEGIN
STRENGTHENING MODESTLY OUT OF THE NORTHEAST TO EAST THIS AFTERNOON
AND EVENING.
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...11
AVIATION/NOWCASTS....11
DATA ACQUISITION.....MJV
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