Area Forecast Discussion
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FXUS62 KKEY 161832
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
230 PM EDT WED APR 16 2014

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST IR
IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF 200 PM DISPLAY
A CONTINUATION OF FAIRLY DEEP CYCLONIC FLOW ACROSS THE ENTIRE CONUS
AND THE GULF OF MEXICO. THERE ARE SEVERAL SMALLER SCALE
PERTURBATIONS WITHIN THE FLOW UPSTREAM OF THE KEYS...WITH THE
CLOSEST IMPULSE NOW EVIDENT OVER THE SOUTHEASTERN GULF OF MEXICO
NORTH OF THE YUCATAN. AT THE SURFACE AND IN THE LOWER LEVELS...THE
COOL/COLD CENTER OF A DOMINANT 1035 MB ANTICYCLONE IS LOCATED NEAR
LAKE ERIE. WELL TO THE SOUTH OF THAT FEATURE...REMNANTS OF A SURFACE
FRONTAL BOUNDARY ARE IN THE OFFSHORE FLORIDA STRAITS PARALLEL TO THE
KEYS ISLAND CHAIN.

.CURRENTLY...AS OF 200 PM...PARTLY TO MOSTLY CLOUDY SKIES ENCOMPASS
THE VIEWING DOME ABOVE THE FLORIDA KEYS AND SURROUNDING
WATERS...OWING TO PRIMARILY LOWER TO MID LEVEL CUMULUS CLOUDS...WITH
UPPER LEVEL CIRRUS ABOVE THAT. TEMPERATURES ACROSS THE KEYS ISLAND
CHAIN HAVE REACHED TO AROUND 80 DEGREES WITH MODERATE HUMIDITY
INDICATED BY DEWPOINTS AROUND 70 DEGREES. C-MAN STATIONS ALONG THE
FLORIDA REEF ARE RECORDING NORTHEAST WINDS NEAR 15 KNOTS AND
GUSTY...AND NEAR 15 MPH ACROSS THE ISLANDS.

.FORECASTS...TONIGHT THRU SATURDAY NIGHT...MODELS CONTINUE TO
INDICATE/SUGGEST A SOMEWHAT AMPLIFIED MIDDLE TO UPPER LEVEL PATTERN
WILL CONTINUE ACROSS THE SOUTHERN CONUS...SOUTH FLORIDA AND THE
FLORIDA KEYS FOR MID TO LATE APRIL. AS SUCH...SEVERAL DISTURBANCES
ARE SUGGESTIVE OF BETTER CHANCES FOR SHOWERS AT THIS CLIMATOLOGICAL
DRY TIME OF YEAR. THE SURFACE TROUGH NEAR THE FLORIDA KEYS WILL HAVE
LESS INFLUENCE THE WEATHER ACROSS THE ISLANDS TONIGHT AND
THURSDAY...WITH A STRONGER GRADIENT DUE TO VERY STRONG HIGH PRESSURE
OVER THE NORTHEASTERN UNITED STATES RESULTING IN FRESHENING BREEZES
BY THURSDAY NIGHT.

ALTHOUGH LESS FORCING IS AVAILABLE TONIGHT AND DURING
THURSDAY...MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE AMPLE LOW
TO MID TROPOSPHERIC MOISTURE IN THE COLUMN...SO HAVE ELEVATED
CHANCES FOR ISOLATED SHOWERS IN THE GRIDS...20%...AND GIVEN STRONGER
WINDS...EXPECT ENOUGH LOWER LEVEL CONVERGENCE TO JUSTIFY LOW
CHANCES FOR RAIN...30%...WITH MOST OF THE SHOWER ACTIVITY EARLY
TOMORROW MORNING AND LATE THURSDAY NIGHT/FRIDAY MORNING.

THEN FOR FRIDAY THRU SATURDAY NIGHT...ALL OF THE LARGER SCALE MODELS
ARE COMING TOGETHER WITH DEVELOPMENT OF AN ANOMALOUSLY FAR SOUTH
LOWER TO MIDDLE LEVEL CYCLONE ACROSS THE EAST CENTRAL GULF OF
MEXICO. CONFIDENCE IS STILL LOW BUT INCREASING THAT RAIN CHANCES
WOULD INCREASE FOR FRIDAY NIGHT THRU SATURDAY NIGHT. FOR NOW WILL
HOLDING WITH LOW CHANCE POPS FOR THESE THREE PERIODS BECAUSE MODEL
FORECAST SOUNDINGS SHOW VERY LITTLE MOISTURE IN THE COLUMN IN
ASSOCIATION WITH A CLOSED 500 MB CYCLONE MOVING ACROSS CENTRAL
FLORIDA DURING SATURDAY. IF MODELS CONTINUE TO SHOW THIS FEATURE IN
24 HOURS...INSTABILITY WOULD SUPPORT THUNDER AND POSSIBLY RAISING
RAIN CHANCES FOR THE FRIDAY NIGHT THUR SATURDAY NIGHT PERIOD.
CONFIDENCE IN EXACT DETAILS IS TOO LOW ATTM...BECAUSE MODELS HAVE
BACKED OFF LAST MINUTE WITH THESE TYPES OF SYSTEMS DURING THE LAST
TWO MONTHS. FOR NOW WILL KEEP LOW CHANCES FOR RAIN...30
PERCENT...WITH ISOLATED THUNDER CONFINED TO THE FLORIDA STRAITS.

EXTENDED...SUNDAY THRU WEDNESDAY...IT DOES APPEAR MID-LEVEL RIDGING
COULD BUILDING TEMPORARILY FROM ACROSS THE CARIBBEAN AND THE GULF OF
MEXICO. THERE IS SOME MOISTURE IN THE LOWER TROPOSPHERE...BUT
GENERALLY PWAT IS FROM THREE QUARTERS OF ONE INCH TO ONE AND ONE
QUARTER OF AN INCH.

&&

.MARINE...A TROUGH OF LOW PRESSURE WILL LINGER NEAR THE FLORIDA KEYS
TONIGHT...BEFORE STRONG HIGH PRESSURE BUILDS IN ACROSS THE FLORIDA
KEYS DURING THURSDAY AND THURSDAY NIGHT. GENTLE TO MODERATE BREEZES
ARE EXPECTED TO CLOCK AROUND FROM SOUTHEAST ON FRIDAY TO NORTH BY
LATE SATURDAY...IN RESPONSE TO A DEVELOPING LOW PRESSURE AREA OVER
THE EASTERN GULF OF MEXICO WHICH IS EXPECTED TO SLIDE ACROSS THE
FLORIDA PENINSULA FRIDAY NIGHT THROUGH SATURDAY NIGHT. WINDS ARE
EXPECTED TO FRESHEN AS THIS SYSTEM DEPARTS LATE IN THE WEEKEND AND
EARLY NEXT WEEK. SMALL CRAFT WILL STILL NEED TO EXERCISE CAUTION FOR
SEAS THIS EVENING. SMALL CRAFT WILL LIKELY NEED TO EXERCISE CAUTION
ACROSS ALL WATERS THURSDAY NIGHT...AND SMALL CRAFT ADVISORIES ARE
POSSIBLE THURSDAY NIGHT AND FRIDAY ACROSS HAWK CHANNEL...THE
OFFSHORE GULF WATERS...AND THE FLORIDA STRAITS. WINDS ARE EXPECTED
TO REMAIN BELOW HEADLINE OR ADVISORY CRITERIA FRIDAY NIGHT THRU
SATURDAY BUT CONFIDENCE IS LOWER THAN USUAL.

THEN SMALL CRAFT WILL LIKELY NEED TO EXERCISE CAUTION AGAIN SUNDAY
THRU MONDAY NIGHT...AND ADVISORIES ARE POSSIBLE ACROSS THE FLORIDA
STRAITS DURING THIS TIME AS WELL.

&&

.AVIATION...EXPECT VFR CONDITIONS TO CONTINUE AT KEY WEST
INTERNATIONAL AND MARATHON AIRPORTS THROUGH THE FORECAST PERIOD.
NORTHEAST WINDS NEAR 10 KNOTS BECOMING MAINLY EAST AFTER MIDNIGHT.

&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  75  83  76  83  73 / 20  30  30  30  30
MARATHON  75  85  76  86  73 / 20  30  30  30  30

&&

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

&&

$$

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

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