Area Forecast Discussion
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000
FXUS62 KKEY 041401
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1000 AM EDT TUE AUG 4 2015

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF
900 AM DEPICT THE CENTER OF AN EXPANSIVE MIDDLE AND UPPER
ANTICYCLONE POSITIONED OVER NORTH CENTRAL OLD MEXICO...SOUTH FLORIDA
AND THE FLORIDA KEYS ARE BENEATH THE EASTERN MOST PERIPHERY OF THE
ANTICYCLONE. THERE IS EVIDENCE OF A FAINT MID-LEVEL TROUGH FEATURE
EVIDENT IN THE 12Z SOUNDING...AROUND 500 MB.

AT THE SURFACE AND IN THE LOWER TO MID LEVELS...SURFACE TO 700
MB...LATEST IR IMAGERY OVERLAID WITH MARINE AND LAND SURFACE
OBSERVATIONS AND ANALYSIS AS OF 900 AM...DETAIL WEAK SURFACE RIDGING
FROM NEAR 30 NORTH 70 WEST EXTENDING WEST SOUTHWESTWARD TO ACROSS
CENTRAL FLORIDA. A WEAK SURFACE LOW IS JUST OFF OF THE SOUTH
CAROLINA COAST. THERE IS A WEAK INVERTED TROUGH POSITIONED
NORTHEAST OF LONG ISLAND BAHAMAS. THE 12Z MORNING SOUNDING IN KEY
WEST ILLUSTRATED GENTLE TO MODERATE SOUTHEAST TO SOUTH TYPICALLY
MOIST FLOW FROM JUST OFF OF THE SURFACE TO ABOUT 500 MB...WITH PWAT
AT 1.87 INCHES.

.FORECAST FOR THE REST OF THE DAY...LIKE YESTERDAY...WEAK LOW-MID LEVEL
RIDGING IS LIKELY TO BE OVERCOME BY STRONG HEATING...BACKING WINDS
THRU 500 MB THIS AFTERNOON NEAR THE ISLANDS. THE FORECAST OF 0-6 KM
SUPPORTS WELL DEVELOPED CLOUDLINES NEAR THE KEYS...FAVORING MORE
THE LOWER AND MIDDLE KEYS. IN ADDITION...PENINSULAR SEABREEZE
CONVECTION OVER MIAMI DADE WOULD SEEP DOWN INTO FLORIDA BAY AND PORTIONS
OF THE UPPER FLORIDA KEYS. MAY MAKE A LAST MINUTE UPDATE TO RAISE UP
RAIN CHANCES FROM LOW TO HI CHANCE...WITH POSSIBILITY OF LOCALLY HEAVY RAIN
AGAIN IN CLOUD LINE SHOWERS.

&&

.MARINE...
AN ATLANTIC RIDGE OF HIGH PRESSURE WILL REMAIN JUST NORTH OF
THE KEYS THROUGH THIS EVENING. THIS RIDGE THEN WILL REMAIN NORTH OF THE
FLORIDA KEYS TONIGHT THROUGH AT LEAST SATURDAY.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH TODAY AND TONIGHT. MVFR
OR LOWER CONDITIONS ARE CONCEIVABLE AT EYW AND MTH FROM ABOUT 18Z TO
AROUND 00Z. THIS POSSIBILITY IS NOT GREAT ENOUGH TO INCLUDE IN THE
TERMINAL FORECASTS AT THIS TIME. SUSTAINED EAST TO SOUTHEAST WINDS
NEAR 10 KNOTS EXPECTED FROM JUST OFF THE SURFACE TO ABOUT 3000 FEET.

&&

.CLIMATE...
ON THIS DATE IN FLORIDA KEYS WEATHER HISTORY...IN 1894...THE LOW
TEMPERATURE IN KEY WEST WAS 68 DEGREES. THIS SET THE DAILY RECORD
FOR MINIMUM TEMPERATURE MEASURED IN KEY WEST ON AUGUST 4TH...A
RECORD WHICH STILL STANDS 121 YEARS LATER. IN ADDITION...THIS LOW
TEMPERATURE OF 68 DEGREES IS TIED AS THE MINIMUM TEMPERATURE EVER
RECORDED IN KEY WEST DURING THE MONTH OF AUGUST. TEMPERATURE RECORDS
AT KEY WEST DATE BACK TO 1872.

&&

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

$$

PUBLIC/MARINE/GRIDS............FUTTERMAN
AVIATION/NOWCASTS/CLIMATE......BS
UPPER AIR/DATA ACQUISITION......CHESSER

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