[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041143
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI DEC 04 2009

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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 8N13W 4N26W 5N45W 4N51W. SCATTERED
SHOWERS AND CLUSTERS OF ISOLATED MODERATE CONVECTION ARE FROM 1N-12N
BETWEEN 26W-44W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0900 UTC...A STATIONARY FRONT EXTENDS FROM THE FLORIDA KEYS
ALONG 23N85W TO THE YUCATAN PENINSULA NEAR 21N88W. MOSAIC DOPPLER
RADAR IMAGERY AND LIGHTNING DATA SHOW ISOLATED SHOWERS AND TSTMS
COVERING THE SOUTHERN FLORIDA PENINSULA AND SE GULF WITHIN 90 NM
EITHER SIDE OF THE FRONTAL BOUNDARY...MAINLY REMAINING S OF 26N E OF
87W. THIS FRONTAL SYSTEM IS SUPPORTED ALOFT BY A LONGWAVE UPPER
LEVEL TROUGH COVERING THE CENTRAL CONUS AND MOIST SWLY UPPER LEVEL
FLOW COVERING THE ENTIRE GULF. NW OF THE FRONT...INCREASED MIDDLE TO
UPPER LEVEL MOISTURE IS OBSERVED IN WATER VAPOR IMAGERY AND
SCATTERED SHOWERS HAVE FORMED OVER THE PAST 6 HOURS WITHIN 90 NM
EITHER SIDE OF A LINE STRETCHING FROM NE FLORIDA NEAR JACKSONVILLE
TO THE SW GULF NEAR 22N96W. THIS SWLY UPPER LEVEL FLOW IS AHEAD OF
THE NEXT MID-LEVEL SHORTWAVE TROUGH CURRENTLY OVER NORTHERN MEXICO
THAT IS EXPECTED TO INDUCE CYCLOGENESIS OVER THE WESTERN GULF BY
FRIDAY AFTERNOON. A SURFACE TROUGH ANALYZED ALONG 96W FROM 20N-28N
IS LOCATED IN THE WESTERN GULF AND APPEARS TO BE THE BEGINNINGS OF
THIS FORMING LOW PRESSURE AREA AS NOTED BY DECREASING PRESSURE
VALUES AT BUOYS 42040 AND 42002 OVER THE PAST 6 HOURS. THE
ASSOCIATED COLD FRONT IS FORECAST TO PUSH EAST THROUGH THE GULF BY
LATE SATURDAY PRODUCING STRONG NORTHERLY WINDS BEHIND THE FRONT.

CARIBBEAN SEA...
A SHARP UPPER LEVEL RIDGE COVERS THE WESTERN CARIBBEAN W OF 70W
ANCHORED IN THE E PACIFIC WITH AXIS EXTENDING ACROSS NICARAGUA
THROUGH THE WINDWARD PASSAGE AND INTO THE W ATLC. STRONG SUBSIDENCE
AND THE LACK OF MOISTURE IS NOTED ON WATER VAPOR IMAGERY WHICH
ACCOMPANIES THE UPPER LEVEL ANTICYCLONIC CIRCULATION BRINGING
GENERALLY CLEAR SKIES TO MUCH OF THE BASIN. HOWEVER...WITH THE
STATIONARY FRONT DRAPED 60 NM NORTH OF THE YUCATAN CHANNEL...
ISOLATED SHOWERS AND TSTMS ARE N OF 20N BETWEEN 84W-87W. EAST OF
70W...AN UPPER LEVEL TROUGH AXIS EMBEDDED WITHIN VERY STRONG
SUBSIDENCE EXTENDS FROM THE CENTRAL ATLC ALONG 16N60W 13N70W TO
NORTHERN COLOMBIA. ISOLATED LOW-LEVEL SHOWERS ARE BEING USHERED IN
ON FRESH TO STRONG TRADEWINDS ACROSS THE EASTERN CARIBBEAN AND
LESSER ANTILLES MAINLY E OF 78W.

ATLANTIC OCEAN...
AT 0900 UTC...A STATIONARY FRONT EXTENDS ACROSS THE W ATLC AND
ENTERS THE DISCUSSION AREA NEAR 32N70W CONTINUING W-SW ALONG 28N78W
TO THE FLORIDA KEYS NEAR 25N81W. SATELLITE IMAGERY AND DOPPLER RADAR
ACROSS SOUTH FLORIDA INDICATE SCATTERED SHOWERS ARE OCCURRING WITHIN
60 NM EITHER SIDE OF THE FRONT. ABUNDANT MOISTURE IS NOTED ALOFT AS
SWLY UPPER LEVEL FLOW DOMINATES ACROSS THE W ATLC W OF 66W.
SCATTERED SHOWERS ARE EMBEDDED WITHIN THIS FLOW STRETCHING FROM THE
NORTHERN FLORIDA PENINSULA NE TO BEYOND 32N78W. THE REMAINDER OF THE
W ATLC IS COVERED BY A SURFACE RIDGE ANCHORED ON A 1027 MB HIGH
CENTERED NEAR 34N46W. THE RIDGE IS SUPPORTED ALOFT BY AN AMPLIFIED
UPPER LEVEL RIDGE AXIS EXTENDING FROM THE WESTERN CARIBBEAN THROUGH
THE WINDWARD PASSAGE TO BEYOND 32N61W. ACROSS THE CENTRAL ATLC...AN
UPPER LEVEL LOW IS CENTERED NEAR 23N42W. THIS UPPER LEVEL FEATURE
SUPPORTS A STATIONARY FRONT THAT ENTERS THE DISCUSSION AREA NEAR
32N38W EXTENDING SW TO 29N46W. A SURFACE TROUGH IS ANALYZED FROM
31N41W TO 23N45W. SCATTERED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF
THE FRONTAL BOUNDARY AND WIDELY SCATTERED MODERATE CONVECTION COVERS
AN AREA E OF THE SURFACE TROUGH FROM 21N-29N BETWEEN 35W-45W. THIS
ACTIVITY IS LARGELY ENHANCED BY CLOSE PROXIMITY TO THE UPPER LEVEL
LOW CENTER. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE
OF A SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED SW OF
PORTUGAL NEAR 37N13W.

$$
HUFFMAN



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