[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131140
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 13 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 8N10W 4N24W 4N45W 2N52W. SCATTERED
MODERATE TO STRONG CONVECTION IS FROM 2N-6N BETWEEN 26W-34.

...DISCUSSION...

GULF OF MEXICO...
THE TAIL END OF A COLD FRONT EXTENDING FROM THE W ATLC IS ACROSS
THE FLORIDA STRAITS TO NEAR 24N83W WITH POSSIBLE ISOLATED
SHOWERS ACROSS THE FLORIDA STRAITS THIS MORNING. ELSEWHERE OVER
THE REST OF THE GULF...BROKEN TO OVERCAST STRATOCUMULUS CLOUDS
COVER THE WRN AND S/CENTRAL PORTIONS OF THE GULF...INCLUDING THE
BAY OF CAMPECHE AND THE YUCATAN PENINSULA. THE LOW CLOUDS W OF
90W ARE ALREADY SHOWING SIGNS OF RETURN SOUTHERLY FLOW THAT IS
IN STORE FOR THE GULF OVER THE NEXT FEW DAYS AHEAD OF THE NEXT
DEVELOPING LOW PRESSURE AREA OVER THE CENTRAL U.S. PLAINS
THROUGH LATE SUNDAY. IN THE MEANTIME...MODERATE TO STRONG
SUBSIDENCE IN STRONG W-NW FLOW ALOFT IS INHIBITING ANY DEEP
CONVECTION ACROSS THE GULF REGION WITH A SURFACE RIDGE EXTENDING
ACROSS THE GULF WHICH IS ANCHORED BY A 1028 MB SURFACE HIGH OVER
CENTRAL ALABAMA.

CARIBBEAN SEA...
A COLD FRONT OVER THE W ATLC ENTERS THE CARIBBEAN SEA THROUGH
ERN CUBA THEN CONTINUES S AS A STATIONARY FRONT THROUGH 19N80W
TO COASTAL NICARAGUA NEAR 12N83W. SCATTERED SHOWERS ARE ALONG
AND WITHIN 90 NM ON EITHER SIDE OF THIS FRONT. BEHIND THE FRONT
BROKEN TO OVERCAST CLOUDINESS WITH EMBEDDED ISOLATED SHOWERS ARE
OBSERVED S OF 21N. THE REMAINDER OF THE CARIBBEAN SEA IS UNDER
THE INFLUENCE OF A STRONG 1039 MB HIGH PRESSURE SYSTEM CENTERED
W OF THE AZORES IN THE CENTRAL ATLC. PATCHES OF LOW LEVEL
MOISTURE STREAM WWD ACROSS THE BASIN ON MODERATE TO FRESH TRADE
WINDS. SATELLITE IMAGERY REVEALS LARGEST SWATH OF LOW TOPPED
SHOWERS FROM 11N-16N W OF 71W. ELSEWHERE ISOLATED AREAS OF
SHOWERS ARE ACROSS THE LEEWARD ISLANDS AND PUERTO RICO THIS
MORNING. ALOFT...UPPER LEVEL ANTICYCLONIC FLOW RESIDES WITH A
RIDGE EXTENDING FROM N COLOMBIA TO THE NW CARIBBEAN NEAR 18N83W.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH OVER THE ERN U.S. SEABOARD SUPPORTS A PAIR
OF COLD FRONTS OVER THE W ATLC. THE MAIN FRONT ENTERS THE
FORECAST AREA NEAR 32N68W AND CONTINUES SW OVER THE CENTRAL
BAHAMAS TO ERN CUBA NEAR 21N77W. THE SECONDARY FRONT CONTINUES
TO WEAKEN AND EXTENDS FROM 31N74W ACROSS THE NW BAHAMAS AND INTO
THE STRAITS OF FLORIDA. SCATTERED SHOWERS ARE WITHIN 200 NM E OF
THE MAIN FRONT N OF 26N AND WITHIN 90 NM OF THE FRONT ELSEWHERE.
THE REMAINDER OF THE ATLC IS UNDER THE INFLUENCE OF A STRONG
1039 MB SURFACE HIGH CENTERED W OF THE AZORES NEAR 37N37W.
SUBSIDENCE AROUND THIS HIGH IS GENERALLY SUPPORTING FAIR WEATHER
CONDITIONS ACROSS MUCH OF THE ERN ATLC. HOWEVER...AN UPPER-LEVEL
TROUGH WITH AXIS ALONG 32N54W 23N50W TO 18N47W AND A SURFACE
TROUGH WHICH EXTENDS FROM 27N55W TO 20N50W ARE GENERATING
SCATTERED SHOWERS AND TSTMS FROM 20N-28N BETWEEN 41W-53W E OF
THE TROUGH. UPPER DIFFLUENCE TO THE SE OF THE UPPER TROUGH IS
ALSO GENERATING SCATTERED SHOWERS FROM 8N-19N BETWEEN 33W-40W.
ANOTHER SURFACE TROUGH EXTENDS ALONG 14N54W TO 9N56W WITH
CYCLONIC CURVATURE NOTED IN THE LOW CLOUD FIELD. BY EARLY NEXT
WEEK...COMPUTER MODELS ARE ANTICIPATING THE FORMATION OF A LOW
PRESSURE SYSTEM OVER THE TROPICAL CENTRAL ATLC AS THE UPPER
LEVEL DEEP LAYERED TROUGH CURRENTLY OVER THE ERN SEABOARD MOVES
EWD.

$$
HUFFMAN




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