Area Forecast Discussion
Issued by NWS Miami, FL

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000
FXUS62 KMFL 181826
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
126 PM EST THU DEC 18 2014

.AVIATION...
HIGH PRESSURE BUILDING OVER THE AREA WILL KEEP VFR CONDITIONS
THROUGH THE TAF PERIOD. HOWEVER, CAN NOT RULE OUT SOME BRIEF, SUB
TEMPO IFR AT A FEW SITES. THIS WOULD BE SIMILAR TO LAST NIGHT,
WITH LIGHT FOG OR LOW CIGS POSSIBLE, BUT NOT LIKELY.

&&

.PREV DISCUSSION... /ISSUED 900 AM EST THU DEC 18 2014/

UPDATE...
A WEAK COLD FRONT WAS WASHING OUT OVER SOUTH FLORIDA THIS MORNING
AND WILL CONTINUE TO WASH OUT THROUGH THE AFTERNOON HOURS...AS
HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTH. THIS WILL KEEP
THE DRY WEATHER IN PLACE TODAY ALONG WITH WEST TO NORTHWEST WIND
FLOW OVER SOUTH FLORIDA. THEREFORE...THE ONLY CHANGE TO THE
FORECAST IS TO RAISE THE HIGH TEMPERATURES A LITTLE BIT FOR THE
EAST COAST METRO AREAS DUE TO THE WESTERLY WIND FLOW. NO OTHER
CHANGES ARE PLANNED AT THIS TIME.

UPDATE...54/BNB

PREV DISCUSSION... /ISSUED 325 AM EST THU DEC 18 2014/

SHORT TERM (TODAY-SATURDAY)...
THE SHORT TERM PERIOD WILL REMAIN BENIGN AND DRY WITH A SLOW
WARMING TREND AS A ZONAL FLOW PATTERN MAINTAINS ITSELF. THIS IS A
RESULT OF A STRONG SUBTROPICAL RIDGE NEARLY STATIONARY OVER THE
CARIBBEAN SEA. THE MID LATITUDES ALSO REMAIN VERY PROGRESSIVE, BUT
WITH SUCH A STRONG RIDGE IN PLACE THESE FEATURES WILL REMAIN WELL
NORTH OF THE FLORIDA PENINSULA. THE SURFACE RIDGE THAT HAD BEEN
OVER SOUTH FLORIDA THE PAST COUPLE OF DAYS HAS DRIFTED SOUTH INTO
THE FLORIDA KEYS AS A WEAKENING COLD FRONT MOVED DOWN THE
PENINSULA. THIS FRONT HAS MOVED INTO SOUTH FLORIDA EARLY THIS
MORNING BUT IS BECOMING RAPIDLY DIFFUSE. A SURFACE TROUGH IS
FORECAST TO MOVE ALONG THE GULF COASTAL REGION AND INTO THE
FLORIDA PANHANDLE LATE SATURDAY BUT WILL HAVE NO EFFECT ON SOUTH
FLORIDA OTHER THAN TO RAISE HUMIDITY LEVELS AS THE WIND VEERS TO A
SOUTHEAST DIRECTION TRANSPORTING SOME LOW LEVEL MOISTURE INTO THE
AREA.

LONG TERM (SUNDAY-WEDNESDAY)...
BOTH THE GFS AND ECMWF APPEAR TO BE IN MUCH BETTER AGREEMENT FOR
THE PAST FEW MODEL RUNS THROUGH THE EXTENDED PERIOD. A SERIES OF
SOUTHERN STREAM DISTURBANCES WILL MOVE THROUGH THE SOUTHEAST
STATES LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A STRONG
MID/UPPER LEVEL TROUGH DEVELOPS OVER THE EASTERN HALF OF NORTH
AMERICA. THIS COULD LEAD TO AN UNSETTLED PATTERN FOR SOUTH FLORIDA
AS THE ATMOSPHERE DESTABILIZES AND MOISTENS. MOST OF THE DEEP
LAYER MOISTURE IS FORECAST TO REMAIN ACROSS NORTH AND CENTRAL
FLORIDA DURING THIS TIME FRAME SO SIGNIFICANT RAINFALL IS NOT
FORESEEN BUT THERE WILL BE INCREASING CHANCE FOR SHOWERS. IN
ADDITION, FORECAST SOUNDINGS ARE INDICATING AN INCREASING CHANCE
FOR THUNDER ESPECIALLY NEAR THE LAKE AND SOUTHWEST COAST FOR
MONDAY AND TUESDAY. HOWEVER, THE GFS IS SHOWING STRONG 850MB WINDS
TO INCREASE ABOVE 30-35 KNOTS AND THIS WOULD INHIBIT THUNDERSTORM
DEVELOPMENT COMBINED WITH THE FACT ANY UPPER AIR DYNAMICS WILL
REMAIN WELL TO OUR NORTH. AS THE AFOREMENTIONED TROUGH CONTINUES
TO DEEPEN, BOTH THE GFS AND ECMWF ARE DEPICTING A COLD FRONT TO
MOVE ACROSS SOUTH FLORIDA ON CHRISTMAS EVE WITH A SLIGHT CHANCE OF
THUNDER ADVANCING TO ALL REGIONS TUESDAY NIGHT AHEAD OF THE FRONT.
THE MODELS HAVE BEEN BATTLING AS TO HOW DEEP THE TROUGH BECOMES
WITH THE 00Z ECMWF SHOWING THE STRONGER TROUGH AND THUS THE COOLER
PUSH OF AIR INTO SOUTH FLORIDA. HOWEVER, THE 12Z RUN DOES NOT SHOW
AS DEEP OF A TROUGH WITH THE GFS NOW HAVING THE STRONGER PUSH OF
COOLER AIR. SO AT THIS TIME IT IS THE WAIT AND SEE APPROACH.

MARINE...
BENIGN BOATING CONDITIONS WILL CONTINUE THROUGH THE EARLY PART OF
THE WEEKEND WITH A LIGHT NORTHWEST TO NORTH WIND THIS MORNING
SLOWLY VEERING TO THE NORTHEAST, THEN SOUTHEAST BY SATURDAY AND
SUNDAY. AS THE NEXT COLD FRONT APPROACHES THE LOCAL WATERS, WIND
WILL CONTINUING VEERING TO THE SOUTH AND SOUTHWEST ON MONDAY. SEAS
WILL REMAIN LESS THAN 4 FEET ALL WATERS THROUGH THE FORECAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  58  75  64  77 /   0   0  10  10
FORT LAUDERDALE  62  76  66  78 /   0  10  10  10
MIAMI            62  76  66  78 /   0   0  10   0
NAPLES           54  75  60  76 /   0   0  10  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

$$

SHORT TERM...54/BNB
LONG TERM....21/KM
AVIATION...13/SI


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