000
AXNT20 KNHC 311747
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST THU DEC 31 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N10W 7N14W 6N22W 3N32W 3N43W 
CROSSING THE EQUATOR NEAR 50W. ITCZ HAS NO SIGNIFICANT DEEP 
CONVECTION. 

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A 1017 MB LOW IS OVER S ALABAMA WITH COLD FRONT 
ENTERING THE GULF JUST E OF PENSACOLA FLORIDA EXTENDING SW ALONG 
26N90W BECOMING NEAR STATIONARY ALONG 25N93W TO 23N94W THEN 
DISSIPATING TO NEAR 21N96W. ISOLATED SHOWERS DOT MOST OF THE 
GULF WITHIN 150 NM OF LINE FROM OVER FLORIDA NEAR 30N84W ALONG 
23N94W TO OVER MEXICO NEAR 20N97W. THE SURFACE RIDGE OVER THE 
FAR E GULF IS RETREATING EASTWARD MOSTLY COVERING THE FLORIDA 
PENINSULA AND ANCHORED BY A 1029 MB HIGH N OF BERMUDA. THE UPPER 
LEVEL TROUGH SUPPORTING THE SURFACE LOW/FRONT COVERS MUCH OF THE 
E US AND IS MOVING INTO THE W ATLC PRODUCING A MODERATE UPPER 
LEVEL JET ACROSS THE N GULF N OF A LINE FROM TAMPICO MEXICO TO 
TAMPA FLORIDA WITH WINDS ESTIMATED TO BE 90 TO 125 KT. THE COLD 
FRONT IS BEGINNING TO STALL AS REINFORCING COLD AIR WILL FILTER 
INTO NW GULF THIS EVENING. 

CARIBBEAN SEA...
THE REMNANTS OF A FRONTAL BOUNDARY ENTERS THE CARIBBEAN OVER THE 
N LEEWARD ISLANDS NEAR 17N62W W TO 17N67W WITH SCATTERED SHOWERS 
N OF 16N TO OVER THE GREATER ANTILLES AND THE VIRGIN ISLANDS E 
OF 70W TO OVER THE LEEWARD ISLANDS. A BROAD UPPER RIDGE COVERS 
THE CARIBBEAN ANCHORED INLAND OVER VENEZUELA WITH STRONG 
SUBSIDENCE AND MOSTLY DRY STABLE OVER THE AREA SUPPRESSING ANY 
DEEP CONVECTION. A SURFACE RIDGE OVER THE W ATLC AND THE FLORIDA 
PENINSULA IS PRODUCING A STRONG PRESSURE GRADIENT OVER THE 
CENTRAL AND W CARIBBEAN GENERATING FRESH TO STRONG EASTERLY 
TRADE WINDS THAT WILL CONTINUE THROUGH THE NIGHT BUT WILL BEGIN 
TO DIMINISH FRI AS REINFORCING COLD AIR MOVES INTO THE NW 
CARIBBEAN. OTHERWISE ISOLATED SHOWERS DOT THE NW CARIBBEAN N OF 
15N W OF 70W LEAVING THE S CARIBBEAN UNDER FAIR WEATHER TODAY. 

ATLANTIC OCEAN...
A SURFACE RIDGE DOMINATES THE W ATLC TO OVER THE FLORIDA 
PENINSULA ANCHORED BY A 1029 MB HIGH N OF BERMUDA WITH A COLD 
FRONT ENTERING THE CENTRAL ATLC NEAR 32N38W EXTENDING SW ALONG 
25N45W TO 19N55W WHERE IT DISSIPATES ACROSS THE N LEEWARD 
ISLANDS INTO THE NE CARIBBEAN NEAR 17N62W. THE UPPER TROUGH 
SUPPORTING THE FRONT COVERS THE AREA N OF 21N BETWEEN 38W-60W. 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 
180 NM E OF THE FRONT N OF 21N WITH SCATTERED SHOWERS WITHIN 120 
NM S OF THE REMAINDER OF THE FRONT AND WITHIN 90 NM N OF THE 
DISSIPATING FRONT. A SECOND SURFACE RIDGE COVERS THE E ATLC 
ANCHORED BY A 1023 MB HIGH NEAR 30N23W. THE UPPER TROUGH 
CURRENTLY OVER THE E US WILL LIFT OUT AHEAD OF A COLD FRONT 
MOVING OFF THE N FLORIDA COAST LATE TONIGHT. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE.

$$
WALLACE