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000
FXUS62 KKEY 011849
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
245 PM EDT MON SEP 1 2014

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF
200 PM DEPICT CONTINUES TO DEPICT THE AXIS OF A MIDDLE TO UPPER
LEVEL ANTICYCLONIC RIDGE SITUATED FROM NORTHERN FLORIDA WEST
SOUTHWESTWARD TO THE WESTERN GULF OF MEXICO. TO THE SOUTHEAST OF
THAT FEATURE...THE AXIS OF A WESTWARD MOVING TROPICAL UPPER
TROPOSPHERIC TROUGH IS APPROACHING LONG ISLAND BAHAMAS AND EASTERN
CUBA. LATEST AVAILABLE MIMIC SCANS STILL ILLUSTRATE COLUMNAR PWAT
(PRECIPITABLE WATER) REMAINS BETWEEN 1.75 AND 2.00 INCHES UPSTREAM
OF THE FLORIDA KEYS.

AT THE SURFACE AND IN THE LOWER TO MID LEVELS...SURFACE TO 700
MB...BROAD LOW PRESSURE CONTINUES TO ORGANIZE ACROSS THE EASTERN BAY
OF CAMPECHE...WITH NHC INDICATING THAT THIS SYSTEM HAS A HIGH CHANCE
OF DEVELOPMENT OVER THE NEXT 48 HOURS. CLOSER TO THE THE FLORIDA
KEYS...THE SOUTHWESTERN PERIPHERY OF A WESTERN ATLANTIC SURFACE
RIDGE OF HIGH PRESSURE CENTERED OVER THE WEST CENTRAL NORTH ATLANTIC
IS DRAPED ACROSS CENTRAL FLORIDA.

.CURRENTLY...AS OF 200 PM...LATEST MARINE AND LAND SURFACE
OBSERVATIONS AND ANALYSIS OVERLAID ON VISIBLE SATELLITE IMAGERY
DETAILS MOSTLY SUNNY SKIES OVER THE ISLANDS AND ADJOINING WATERS.
KEY WEST RADAR DETECTS JUST ISOLATED SHOWERS AND A FEW
THUNDERSTORMS ACROSS THE WATERS SURROUNDING THE LOWER KEYS. C-MAN
STATIONS ALONG THE FLORIDA REEF...FLORIDA BAY...AND SMITH SHOAL
LIGHT ARE REGISTERING SOUTHEAST WINDS BETWEEN 10 AND 15 KNOTS AND
GUSTY. TEMPERATURES RIGHT OVER THE ISLANDS ARE NEAR 90 DEGREES WITH
DEWPOINTS IN THE MIDDLE TO HI 70S.

.SHORT TERM...TODAY THRU THURSDAY...A TYPICALLY HOT & UNCOMFORTABLE
WEATHER PATTERN CONTINUES AS WE ENTER THE NEAR PEAK/PEAK OF BOTH THE
WET AND TROPICAL SEASON 2014. MODEST SURFACE RIDGING WILL REMAIN
NORTH OF THE FLORIDA KEYS. DO ANTICIPATE ANOTHER SURGE TONIGHT...BUT
THEN WINDS WILL REMAIN GENTLE TO MODERATE THROUGH THE REST OF THE
WEEK. THIS IS GIVEN THE GRADIENT BETWEEN LOW PRESSURE WELL TO THE
SOUTHWEST AND THIS RIDGING WILL ALLOW FOR A SOMEWHAT LESS PROMINENT
SURGE AGAIN TONIGHT...AND ABUNDANT MOISTURE IN THE BOUNDARY LAYER
WITH PWAT AROUND 2.00 INCHES...SO WILL MAINTAIN MIDDLE OF THE ROAD
CHANCES...40%...FOR THE OVERNIGHT...WHICH IS ACTUALLY JUST SLIGHTLY
ABOVE CLIMO ATTM. THEN 12Z MODEL FORECAST SOUNDINGS DO INDICATE
SLIGHT BACKING OF THE WINDS ON TUESDAY AND TUESDAY EARLY
EVENING...WHICH MAY ALLOW FOR MESOSCALE CLOUDLINES TO DEVELOP...SO
LOW CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS ARE INDICATED FOR
BOTH PERIODS IN THE GRIDS.

THEREAFTER MODEL INDICATIONS FOR WEDNESDAY THROUGH THURSDAY CONTINUE
TO DEVELOP MIDDLE AND UPPER LOW PRESSURE OVER THE BAHAMAS (UPSTREAM
OF THE KEYS)...BUT THIS SYSTEM IS PROGGED TO MOVE ACROSS THE KEYS
AND SURROUNDING WATERS AS IT STARTS TO UNRAVEL...BUT GIVEN THAT IT
MAY BE ACCOMPANIED BY SOMEWHAT DEEPER MOISTURE AND INSTABILITY AND
INSTABILITY...THAN WE HAVE SEEN AS COMPARED WITH THE PAST TUTT CELLS
THUS FAR THIS SEASON...WE WILL HOLD WITH MIDDLE OF THE ROAD CHANCES
FOR SHOWERS AND STORMS THROUGH THESE 3 PERIODS.

EXTENDED...THURSDAY NIGHT THRU MONDAY...TROPICAL WAVES UPSTREAM NOW
OVER THE ATLANTIC WILL CONTINUE TO BATTLE ELEMENTS THAT ARE
NON-FAVORABLE...BUT THE BOUNDARY LAYER IS PROGGED TO REMAIN QUITE
MOIST AND GIVEN GENTLE WINDS THE MESOSCALE MAY CONTRIBUTE TO GREATER
RAIN CHANCES. MIDDLE LEVEL HEIGHTS ALSO SEEM TO INDICATE MORE
INSTABILITY WITH COOLER 500 MB TEMPS. WE ARE CARRYING 40% AT THE
MOMENT BUT THIS MAY BE ABLE TO BE LOWERED UNLESS THERE IS MORE OF A
BACKING WIND PROFILE IN THE FORECAST SOUNDINGS. NO CHANGES.
&&

.MARINE...WINDS AND SEAS APPEAR TO HAVE DROPPED BELOW HEADLINE OR
ADVISORY CRITERIA AND MARINE ZONES HAVE BEEN REGROUPED TO THEIR
STANDARD CONFIGURATIONS. NEVERTHELESS...SEAS MAY AVERAGE A FOOT
HIGHER ACROSS THE WESTERN STRAITS IN ANOTHER LATE NIGHT SURGE...BUT
ALL AND ALL WINDS AND SEAS WILL BECOME MORE CONDUCIVE TO GENERAL
RECREATION STARTING TUESDAY THRU THE REST OF THE WEEK.

&&

.AVIATION...
UNTIL 12Z/2ND...OUTSIDE OF A BRIEF MVFR ENCOUNTER AT THE KEY WEST
AND MARATHON TERMINALS...VFR CONDITIONS WILL PREVAIL. EAST TO
SOUTHEAST WINDS OF 8 TO 11 KNOTS WITH GUSTS BETWEEN 15 AND 18 KNOTS
WILL SLACKEN TO LESS THAN 10 KNOTS THIS EVENING OR TONIGHT.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY BACK IN 1980...THE DAILY RECORD
RAINFALL OF 3.25" WAS RECORDED. RAINFALL RECORDS FOR KEY WEST DATE
BACK TO 1871.

&&

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

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  83  91  82  91  81  / 30  30  30  40  40
MARATHON  83  92  82  90  81  / 30  30  30  40  40

&&

$$

PUBLIC/MARINE/GRIDS.................DAF
AVIATION/NOWCASTS/CLIMATE...........APA
DATA COLLECTION/UPPER AIR...........SC/BF

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