Area Forecast Discussion
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000
FXUS62 KKEY 020226
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1026 PM EDT TUE SEP 1 2015

.DISCUSSION...
THE SKIES ARE MOSTLY CLEAR OVER THE FLORIDA KEYS THIS EVENING...AND
LATEST KEY WEST DOPPLER RADAR SCANS ARE VOID OF PRECIPITATION ECHOES.
CURRENT AIR TEMPERATURES NEAR 86F AND DEWPOINT TEMPERATURES NEAR 77F
YIELD HEAT INDICES NEAR 97F IN THE FLORIDA KEYS...MAKING IT A
TYPICALLY SULTRY EARLY SEPTEMBER EVENING. A GRADUALLY LOWERING SUN
ANGLE AND INCREASED CLOUD COVER SHOULD TAKE THE EDGE OFF THE HEAT
AND HUMIDITY IN ANOTHER FEW WEEKS.

A REGIONAL SURFACE ANALYSIS THIS EVENING REVEALS AN AMORPHOUS HIGH
PRESSURE CELL CENTERED JUST EAST AND NORTH OF THE BAHAMAS...WITH AN
ILL-DEFINED RIDGE EXTENDING TO THE SOUTHERN FLORIDA PENINSULA.
GRADIENT FLOW SOUTH OF THE RIDGE IS FAIRLY WEAK...AS ARE LOCAL
BREEZES. MOST LAND STATIONS ARE REPORTING EAST WINDS 5-10 MPH...WHILE
WIND SPEEDS AT MARINE STATIONS ARE MORE VARIABLE...RANGING FROM
7-12KT. A SUPPORTING DEEP LAYER MEAN ANTICYCLONE PREVAILS ATOP THE
SURFACE HIGH JUST NORTH OF THE BAHAMAS...AND LARGE-SCALE SUBSIDENCE
CLEARLY HAS PREVAILED ACROSS THE KEYS DURING THE LAST 24
HOURS...EVIDENCED BY BOTH UPPER-AIR DATA AND OBSERVED WEATHER. DATA
FROM THE KEY WEST EVENING RADIOSONDE BALLOON INDICATED MODERATE
INSTABILITY WITH SIGNIFICANT LOW-LEVEL CONVECTIVE INHIBITION ENERGY.
IN ADDITION...DESPITE A HIGH TOTAL PRECIPITABLE WATER VALUE OF 1.9O
INCHES...SOME DRY POCKETS WERE PRESENT ALOFT...WITH SOME OF THAT DRY
AIR EXTENDING PRETTY FAR DOWN INTO THE LOWER TROPOSPHERE -- DEWPOINT
DEPRESSION AT 925MB WAS 7C.

THE FORECASTS PROVIDED BY THE AFTERNOON SHIFT REMAIN GENERALLY VALID
AT THIS STAGE...SHOWING MOSTLY CLEAR SKIES...ISOLATED SHOWER AND
THUNDERSTORM COVERAGE...LIGHT TO GENTLE MAINLY EAST BREEZES...AND LOW
TEMPERATURES ABOVE 80F. AS NOCTURNAL FLOW TURNS MORE CONFLUENT ACROSS
THE SERVICE AREA...A FEW SHOWERS AND STORMS SURELY WILL
INITIATE...ESPECIALLY AS OLD OUTFLOW BOUNDARIES FROM ANDROSIAN AND
CUBAN AFTERNOON SEA-BREEZE STORMS MIGRATE INTO THE AREA.
NEVERTHELESS...EXPECT THE BEST CHANCE OF RAIN LATE.
&&

.MARINE...
NO ADVISORIES AND NO HEADLINES. A WEAK HIGH PRESSURE CELL OVER THE
SUBTROPICAL ATLANTIC WILL MOVE WESTWARD...AND EXTEND ACROSS SOUTHERN
FLORIDA OVERNIGHT AND WEDNESDAY. THIS AREA OF HIGH PRESSURE WILL
REMAIN OVER OR NEAR THE FLORIDA PENINSULA THURSDAY THROUGH SUNDAY.
GENTLE EAST TO SOUTHEAST BREEZES WILL PERSIST ACROSS FLORIDA KEYS
COASTAL WATERS TONIGHT THROUGH FRIDAY. LIGHTER AND MORE VARIABLE
BREEZES ARE POSSIBLE ON SATURDAY AND SUNDAY.
&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH TONIGHT AND WEDNESDAY.
MVFR CEILINGS...BASED AT AROUND 2500 FEET...ARE CONCEIVABLE AT EYW
AND MTH WEDNESDAY AFTERNOON. THIS POSSIBILITY IS NOT GREAT ENOUGH TO
INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. SUSTAINED NORTHEAST
TO EAST WINDS NEAR 10 KNOTS EXPECTED FROM JUST OFF THE SURFACE TO
ABOUT 3000 FEET.
&&

.CLIMATE...
ON THIS DATE IN FLORIDA KEYS WEATHER HISTORY...IN 1956...THE HIGH
TEMPERATURE AT KEY WEST INTERNATIONAL AIRPORT WAS 95 DEGREES. THIS
SET THE DAILY RECORD FOR MAXIMUM TEMPERATURE MEASURED IN KEY WEST ON
SEPTEMBER 1ST...A RECORD WHICH STILL STANDS 59 YEARS LATER. IN
ADDITION...THIS HIGH TEMPERATURE OF 95 DEGREES IS TIED AS THE MAXIMUM
TEMPERATURE EVER RECORDED IN KEY WEST DURING THE MONTH OF SEPTEMBER.
TEMPERATURE RECORDS AT KEY WEST DATE BACK TO 1872.
&&

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

$$

PUBLIC/MARINE.........KASPER
AVIATION/NOWCASTS.....BS
DATA COLLECTION.......FLING

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