000
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