000
AXNT20 KNHC 042348
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N11W 5N20W 3N30W 1N45W. SCATTERED 
MODERATE CONVECTION IS FROM 5N-8N BETWEEN 32W-41W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF OF MEXICO IS BECOMING COMPLICATED WITH NEWLY DEVELOPING 
SYSTEMS. AS OF 2100 UTC...A WARM FRONT IS ANALYZED ACROSS THE S 
FLORIDA PENINSULA FROM A 1010 MB LOW NEAR 25N85W ACROSS S FLORIDA 
NEAR NAPLES AND A STATIONARY FRONT EXTENDS SW FROM THE SAME LOW TO 
THE N COAST OF THE YUCATAN PENINSULA NEAR 21N88W WITH SCATTERED 
SHOWERS/THUNDERSTORMS WITHIN 120 NM S OF THE WARM FRONT E OF 84W. AT 
2100 UTC OVER THE W GULF IS A SECOND COMPLEX SYSTEM WITH A 1010 MB 
LOW CENTERED NEAR 27N93W AND A FRONTAL BOUNDARY EXTENDING S ALONG 
25N94W TO A 1011 MB LOW NEAR 22N93W CONTINUING INTO S MEXICO NEAR 
VERACRUZ. THIS ENTIRE SCENARIO IS BEING SUPPORTED BY A BROAD UPPER 
TROUGH THAT EXTENDS FROM THE CENTRAL PLAIN STATES OVER THE GULF TO 
THE FLORIDA PENINSULA. AN ABUNDANCE OF MOISTURE DOMINATES MUCH OF 
THE GULF AND IS GENERATING SCATTERED SHOWERS WITH POSSIBLE ISOLATED 
THUNDERSTORMS OVER THE ENTIRE AREA WITH THE EXCEPTION OF ALONG THE 
TEXAS COAST WHERE IT IS BEGINNING TO CLEAR. A SURFACE RIDGE IS 
ANCHORED OVER CENTRAL TEXAS AND THE RESULTING TIGHTENING PRESSURE 
GRADIENT IS GIVING THE NW GULF WINDS TO GALE FORCE. EXPECT SHOWER 
ACTIVITY TO CONTINUE ACROSS THE MUCH OF THE GULF DURING THE NEXT 24 
HOURS AS THE WESTERN FRONT TRACKS EAST AND MERGES WITH THE EASTERN 
FRONTAL BOUNDARY. 

CARIBBEAN SEA...
A BROAD UPPER RIDGE COVERS THE CARIBBEAN ANCHORED IN THE E PACIFIC 
EXTENDING ACROSS NICARAGUA/COSTA RICA THROUGH THE WINDWARD 
PASSAGE INTO THE W ATLC. STRONG SUBSIDENCE AND THE LACK OF MOISTURE 
CONTINUES ACROSS THE BASIN BRINGING TRANQUIL WEATHER AND FAIR SKIES 
TO MUCH OF THE AREA. SCATTERED SHOWERS AND POSSIBLE ISOLATED 
THUNDERSTORMS ARE OVER THE E CARIBBEAN N OF 13N E OF 70W TO OVER THE 
LESSER ANTILLES. FRESH TO STRONG TRADEWINDS CONTINUE ACROSS THE AREA 
AND ARE BANKING LOW LEVEL CLOUDS WITH ISOLATED SHOWERS WITHIN 60 NM 
OF A LINE FROM 16N80W TO OVER HONDURAS NEAR 15N84W. 

ATLANTIC OCEAN...
A FRONTAL BOUNDARY EXTENDS INTO THE W ATLC NEAR 32N70W CROSSING 
FLORIDA NEAR VERA BEACH INTO THE GULF OF MEXICO WITH SCATTERED 
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM SE OF THE FRONT N OF THE 
FRONT TO INLAND OVER THE SE US. THE UPPER RIDGE THAT COVERS THE 
CARIBBEAN EXTENDS THROUGH THE WINDWARD PASSAGE TO BEYOND 32N52W 
DOMINATING THE W AND INTO THE CENTRAL ATLC. AN UPPER LOW IS IN THE 
S/CENTRAL ATLC NEAR 19N45W SUPPORTING A SURFACE TROUGH THAT EXTENDS 
FROM 26N41W TO 18N46W WITH SCATTERED SHOWERS FROM 16N-20N BETWEEN 
41W-46W. THE REMNANTS OF A SURFACE TROUGH ENTERS THE REGION NEAR 
31N44W SW TO 26N50W. A BROAD SURFACE RIDGE DOMINATES THE ATLC BASIN 
FROM THE E ATLC W TO NEAR BERMUDA WITH A WEAKNESS IN THE CENTRAL 
ATLC IN THE VICINITY OF THE SURFACE TROUGHS ANCHORED BY A 1026 MB 
HIGH IN THE E ATLC NEAR THE MADEIRA ISLANDS AND A 1025 MB HIGH NEAR 
33N46W. 

$$
GARCIA/WALLACE