Area Forecast Discussion
Issued by NWS

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FXUS62 KKEY 161346 CCA
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS...RESENT
NATIONAL WEATHER SERVICE KEY WEST FL
930 AM EDT WED APR 16 2014

CORRECTED DATE

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST IR
IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF 900 AM DISPLAY
BROADLY CYCLONIC FLOW ACROSS THE ENTIRE CONUS AND THE GULF OF
MEXICO...WITH SEVERAL SMALL IMPULSES UPSTREAM OF SOUTH FLORIDA AND
THE KEYS ATTM...OR WITHIN THE MIDDLE AND UPPER FLOW ACROSS NORTHERN
OLD MEXICO AND THE GULF OF MEXICO.

AT THE SURFACE AND IN THE LOWER TO MIDDLE LEVELS...SURFACE TO 700
MB...LATEST MARINE AND LAND SURFACE OBSERVATIONS AND ANALYSIS
OVERLAID ON SATELLITE IMAGERY AS OF 900 AM...DETAIL THE CENTER OF A
LATE CHILLY NEAR 1030 MB HIGH PRESSURE CENTER OVER THE MIDDLE OHIO
VALLEY. A SURFACE TO 950 MB COOL FRONTAL BOUNDARY IS ANALYZED DOWN
TO NEAR THE FLORIDA KEYS ATTM...WHICH IS THE TERMINUS OF THE
ATTENDANT COLD FRONTAL BOUNDARY FROM A COLD LOW PRESSURE SYSTEM OVER
NORTHEAST CANADA.

.CURRENTLY...AS OF 900 AM...SKIES ARE MOSTLY CLOUDY ACROSS THE
ISLANDS AND ADJOINING WATERS. RADAR DETECTS WIDELY SCATTERED SHOWERS
AND A FEW THUNDERSTORMS ACROSS WATERS SOUTH OF THE KEYS.
TEMPERATURES ALONG THE ISLAND CHAIN HAVE REACHED INTO THE MIDDLE 70S
WITH DEWPOINTS AROUND 70 DEGREES. THE 12Z SOUNDING ILLUSTRATED A
MODERATELY MOIST LOWER TO MID TROPOSPHERE WITH TOTAL COLUMNAR PWAT
AT 1.61 INCHES AND GENTLE TO MODERATE NORTHERLIES FROM THE SURFACE
TO 850 MB...THEN BECOMING GENTLE TO MODERATE SOUTHWESTERLY ABOVE
THAT UP TO ABOUT 700 MB...INDICATIVE OF SOME WEAK ISENTROPIC
LIFT...WHICH IS PROVIDING SUPPORT FOR THE AFOREMENTIONED WIDELY
SCATTERED SHOWERS A FEW THUNDERSTORMS.

.FORECASTS...REST OF TODAY...RELIABLE MODELS INDICATE THAT ANY
DELINEATION OF THE COOL SURFACE FRONTAL BOUNDARY EVIDENT IN THE
LOWEST LEVEL...OR FROM THE SURFACE TO 850 MB...SHOULD DISAPPEAR BY
SUNSET...OR AS WE SAY "WASH OUT" BY DAYS END. NEVERTHELESS...VERY
WEAK LARGE SCALE LIFT IN ASSOCIATION WITH TROUGHING AS WELL AS THE
FRONTAL STRUCTURE DOES SUPPORT WIDELY SCATTERED SHOWERS THROUGH THER
BALANCE OF THE AFTERNOON...BUT ANY LIGHTNING WOULD PROBABLY CONTINUE
TO BE OVER THE GULF STREAM...SO WILL KEEP THUNDER OUT OF THE GRIDS
ATTM. DESPITE STRONG 1030 MB SURFACE RIDGING ACROSS THE OHIO VALLEY
AND NORTHEAST STATES...THE RELATIVE PROXIMITY OF THE SURFACE AND
MIDDLE TO UPPER LEVEL TROUGHING WILL NOT ALLOW FOR SURFACE WINDS TO
INCREASE THAT MUCH MORE LATER THIS MORNING/EARLY THIS AFTERNOON. ALL
OF THIS HAS BEEN ADDRESSED IN THE PREVIOUS FORECAST. ONLY CHANGES
WOULD BE TO REMOVE TRANSITIONAL WORDING TO ACCOUNT FOR MINOR CHANGES.

&&

.MARINE...GIVEN THE STRONGER NORTHWESTERLY WINDS AND RESULTANT
COMBINED SEAS AND RELATED SWELL ORIGINATING FROM THE NORTHERN AND
CENTRAL GULF OF MEXICO FROM THE LAST FEW DAYS...SEAS ARE ELEVATED
ACROSS BOTH THE WESTERN FLORIDA STRAITS AND THE OFFSHORE GULF OF
MEXICO WATERS BEYOND 5 FATHOMS. HENCE...A CAUTIONARY STATEMENT FOR
SEAS WILL REMAIN IN PLACE ACROSS WATERS WEST OF THE 7 MILE BRIDGE TO
THE TORTUGAS AND THE OFFSHORE GULF WATERS 20 TO 60 NM WEST OF
MAINLAND MONROE...INCLUDING THE DRY TORTUGAS AND REBECCA SHOAL
CHANNEL.

&&

.AVIATION...OCCASIONAL MVFR CEILINGS FROM 015 TO 025 WILL BE
POSSIBLE UNTIL 15Z...OTHERWISE VFR CONDITIONS AT KEY WEST
INTERNATIONAL AND MARATHON AIRPORTS THROUGH THE FORECAST PERIOD.
WINDS WILL BE NORTHWEST NEAR 10 KNOTS THROUGH THE MORNING...BECOMING
NORTHEAST THIS AFTERNOON. A FEW ISOLATED SHOWERS ARE POSSIBLE MAINLY
OVER THE ATLANTIC WATERS SOUTH OF KEY WEST INTERNATIONAL. A
SPRAWLING HIGH PRESSURE CELL WILL EXTEND FROM NEW ENGLAND TO THE
GULF OF MEXICO TONIGHT THROUGH THURSDAY NIGHT. A LOW PRESSURE AREA
THEN WILL DEVELOP FROM THE NORTHEASTERN GULF OF MEXICO TO THE
ATLANTIC NORTH OF THE BAHAMAS FRIDAY THROUGH SATURDAY.

&&

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

&&

$$

PUBLIC/MARINE/GRIDS....DAF
AVIATION/NOWCASTS......FJ
DATA COLLECTION........CLR

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