Area Forecast Discussion
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FXUS62 KKEY 120905
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
400 AM EST FRI FEB 12 2016

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF
300 AM DETAIL A FULL LATITUDE LOW AMPLITUDE ANTICYCLONE ACROSS THE
WESTERN CONUS AND WESTERN OLD MEXICO...WITH A MUCH WIDER MID AND
UPPER POLAR TROUGH ENCOMPASSING THE EASTERN TWO THIRDS OF THE UNITED
STATES...THE GULF OF MEXICO AND THE NORTHWESTERN CARIBBEAN
SEA...WITH A TROUGH AXIS FROM WESTERN QUEBEC DOWN TO THE FLORIDA
PENINSULA. A SPEEDY MID AND UPPER JET MOVES ALONG THE BASE OF THESE
LARGE FEATURES WITH 100 KNOTS AT 250 MB MOVING JUST SOUTH OF THE
FLORIDA STRAITS.

AT THE SURFACE AND IN THE LOWER TO MIDDLE LEVELS...SURFACE TO 700
MB...LATEST IR IMAGERY OVERLAID WITH AVAILABLE SURFACE LAND AND
MARINE OBSERVATIONS AND ANALYSIS AS OF 300 AM DETAIL THE CENTER OF A
COOL 1027 MB RIDGE NEAR BUOY 42054 IN THE GULF...BUT WITH
INTENSIFYING NEAR 1030 MB SURFACE RIDGING CENTERED OVER VIRGINIA. AS
A RESULT...LAST EVENINGS 00Z SOUNDING AT KEY WEST ILLUSTRATED A VERY
DRY LOWER TO MID TROPOSPHERE WITH GENTLE TO MODERATE NORTHEAST WINDS
FROM THE SURFACE TO 700 MB...AND OVERALL PWAT AT 0.41 INCHES.

.CURRENTLY...SKIES ARE MOSTLY CLEAR ACROSS THE ISLANDS AND
SURROUNDING WATERS AS OF 300 AM...WITH TEMPERATURES OVER THE ISLANDS
IN THE UPPER 50S TO LOWER 60S WITH DEWPOINTS RISING INTO THE LOWER
TO MID 50S. WINDS ARE DECOUPLED OVER THE ISLANDS AND ACROSS
SHALLOW COOLER BAY AND NEARSHORE WATERS TO THE NORTH...BUT C-MAN
STATIONS ALONG THE FLORIDA REEF ARE REGISTERING NORTHEAST WINDS AT 10
TO 15 KNOTS...BUT ARE BETWEEN 15 AND 20 KNOTS ACROSS THE
WARMER ATLANTIC WATERS TO THE SOUTH OF THE REEF.

.SHORT TERM...SEVERAL DAYS OF BENIGN...TODAY THRU TUESDAY...DRIER
AND COOLER WEATHER WILL CONTINUE RULE THE ROOST...UNLIKE MOST OF THIS
EL NINO WINTER THUS FAR. DEEP MID AND UPPER CYCLONE WILL LIFT OUT AND
FLATTEN OVER THE EASTERN CONUS BY SUNDAY...BUT ANOTHER MID LEVEL
DISTURBANCE DIVING SOUTHWARDS OUT OF CANADA WILL CARVE OUT THE
LONGWAVE TROUGH EARLY NEXT WEEK...BRINGING ANOTHER COLD ACROSS SOUTH
FLORIDA AND THE KEYS DURING TUESDAY. BUT AHEAD OF THAT...SURFACE
RIDGING NEARBY OVER THE EAST CENTRAL GULF TODAY WILL ELONGATE TO
ACROSS THE FLORIDA PENINSULA BY TONIGHT...BUT THE CENTER OF A 1040
MB PLUS ANTICYCLONE OVER IOWA ON SATURDAY WILL PLUNGE SOUTHEAST TO
THE MID ATLANTIC STATES TO EASTERN VIRGINIA BY SUNDAY
AFTERNOON...THEN INTO THE NORTHWEST ATLANTIC DURING MONDAY...BEFORE
A DEVELOPING SURFACE LOW OVER ALABAMA DEEPENS OVER THE CAROLINAS
MONDAY NIGHT THEN SWINGING THE SURFACE FRONT THRU ON TUESDAY.

GIVEN ALL THAT...LATEST AVAILABLE ECMWF AND GFS MODEL FORECAST
SOUNDINGS ILLUSTRATE VERY DRY AIR REMAINS IN PLACE TODAY THRU SUNDAY
NIGHT...WITH PWAT REMAINING WELL BELOW 1.00 INCHES IN THE COLUMN.
HIGH TEMPERATURES ONLY AROUND 70 TODAY...COOL AGAIN TONIGHT WITH
LIGHT TO GENTLE WINDS AND RADIATIONAL COOLING ALLOWING TEMPERATURES
TO FALL DOWN TO NEAR 60...BUT LOWER IN SOME NORMALLY COOLER
LOCATIONS WITHIN THE LARGER KEYS...THEN ONLY
REACHING THE LOWER 70S ON SATURDAY...AS A LOWER LEVEL TROUGH KEEPS
THE WINDS BACKED MORE TO THE NORTH. TEMPERATURES FALL BACK TO NEAR 60
AGAIN SATURDAY NIGHT. THEN AS THE AFOREMENTIONED RIDGE INTENSIFIES
AND REACHES THE MID ATLANTIC COAST FOR SUNDAY AND SUNDAY NIGHT...AIR
TEMPERATURES WILL REACH INTO THE MIDDLE 70S ON SUNDAY...FALLING BACK
TO THE MID 60S IN SUNDAY NIGHT...NEAR NORMAL...THEN RISING TO THE
UPPER 70S ON WASHINGTONS BIRTHDAY AS WINDS VEER AROUND TO SOUTHEAST
SUNDAY NIGHT AND MONDAY.

ENOUGH MOISTURE SUPPORTS THE REINSERTION OF ISOLATED CHANCE FOR
SHOWERS SUNDAY NIGHT AND MONDAY. DURING MONDAY NIGHT...THE DEVELOPING
LOW OVER ALABAMA ALLOWS FOR INCREASING SOUTH WINDS AND LOWER LEVEL
CONFLUENCE...SO FOR NOW HAVE LOW CHANCES FOR SHOWERS. THEN ON
TUESDAY...LOOKS LIKE THE DISTURBANCE MOVES BY TO THE NORTH IN TANDEM
WITH THE APPROACHING COLD FRONT...WITH ECMWF DEPICTING ANONYMOUSLY WET
CONDITIONS VERSUS THE GFS. FOR NOW WILL HOLD WITH MIDDLE OF THE ROAD
POPS FOR TUESDAY...40 PERCENT GIVEN THE GFS.

.TUESDAY NIGHT THRU THURSDAY...THE NEXT FRONT WOULD ALLOW A RETURN
TO NEAR NORMAL DAYTIME HIGH AND LOW TEMPERATURES RIGHT NEAR SEASONAL
AVERAGES.

&&

.MARINE...FOR TODAY AND TONIGHT...GIVEN THE PROXIMITY OF THE SURFACE
RIDGE...WINDS WILL DECREASE A FEW KNOTS OUT IN THE STRAITS...REACHING
15 KNOTS LATER IN THE MORNING...BUT DO NOT HAVE AN ASCAT PASS ATTM.
DECOUPLING WILL MAINTAIN LIGHT TO GENTLE WINDS ACROSS THE COOL
NEARSHORE GULF AND BAY WATERS. WINDS WILL INCREASE AGAIN ACROSS HAWK
CHANNEL...THE OFFSHORE GULF WATERS...AND THE STRAITS AGAIN ON
SATURDAY AS THE RIDGING OVER THE PLAINS BUILDS SOUTHEAST TO
THE MID ATLANTIC THROUGH THE REST OF THE WEEKEND...WITH CAUTIONARY
CONDITIONS SATURDAY NIGHT AND SUNDAY ACROSS THE OFFSHORE GULF WATERS
AND HAWK CHANNEL...WITH SMALL CRAFT ADVISORY CONDITIONS RETURNING TO
THE FLORIDA STRAITS FOR SATURDAY NIGHT THROUGH MONDAY.

CAUTIONARY CONDITIONS POSSIBLE ACROSS THE STRAITS MONDAY NIGHT IN
ADVANCE OF THE NEXT COLD FRONT DURING TUESDAY...WITH WINDS INCREASING
AGAIN FOR TUESDAY NIGHT ACROSS THE DEEPER WATERS...BUT SEAS/BAY
WATERS ACROSS THE SHALLOWER WATERS WILL REMAIN DECOUPLED GIVEN THE
COOLER TEMPERATURES OF THE WATERS,

&&

.AVIATION...
UNTIL 00Z/13TH...VFR CONDITIONS WILL PREVAIL AT THE KEY WEST AND
MARATHON TERMINALS...WITH MOSTLY NORTHEAST WINDS OF 10 KNOTS OR
LESS.

&&

.CLIMATE...IN 1973...THE DAILY RECORD LOW TEMPERATURE OF 51F WAS
LAST RECORDED IN KEY WEST. TEMPERATURE RECORDS HAVE BEEN KEPT SINCE
1872.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  73  63  73  62 / 0 0 0 -
MARATHON  73  61  73  60 / 0 0 0 -

&&

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

$$

PUBLIC/MARINE.........FUTTERMAN
AVIATION/NOWCASTS.....APA

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