000
AXNT20 KNHC 162351
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST THU DEC 16 2010

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...
ITCZ AXIS IS CENTERED ALONG 6N9W 6N24W 3N31W 2N41W EQ49W. A WEAK 
SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 10N22W TO 
4N25W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 
6N-9N BETWEEN 13W-17W. SCATTERED MODERATE CONVECTION IS FROM 
2N-6N BETWEEN 25W-29W. 

...DISCUSSION...

GULF OF MEXICO...
THE UPPER LEVEL PATTERN ACROSS THE GULF HAS RELAXED GIVING THE 
AREA WESTERLY FLOW ALOFT ACROSS THE ENTIRE BASIN. STRONG 
SUBSIDENCE AND DRY STABLE AIR ALOFT CONTINUES TO DOMINATE THE 
AREA WITH A SURFACE RIDGE ANCHORED BY A 1019 MB HIGH IN THE W 
ATLC COVERING THE E GULF E OF 85W. LOWER PRESSURE IS IN CONTROL 
OF THE REMAINDER OF THE GULF AS WELL AS SOUTHERLY RETURN FLOW AS 
A COLD FRONT APPROACHES THE NW GULF CURRENTLY JUST INLAND OVER 
THE TEXAS AND IS EXPECTED TO MOVE INTO THE GULF WATERS LATER 
THIS EVENING. ISOLATED SHOWERS ARE AHEAD OF THE FRONT N OF 27N 
TO INLAND OVER THE NE GULF BETWEEN 83W-91W LEAVING THE REMAINDER 
OF THE GULF WITH FAIR WEATHER THIS EVENING. 

CARIBBEAN SEA...
A BROAD UPPER RIDGE ANCHORED IN THE W TROPICAL ATLC DOMINATES 
MOST OF THE CARIBBEAN W OF A LINE FROM SW HAITI TO THE 
NICARAGUA/COSTA RICA BORDER. TROPICAL MOISTURE REMAINS ACROSS 
THE CARIBBEAN WITH THE REMNANTS OF A FRONTAL BOUNDARY ACROSS THE 
NE CARIBBEAN FROM THE LEEWARD ISLANDS NEAR 17N62W ALONG 16N67W 
16N76W WITH POSSIBLE ISOLATED SHOWERS WITHIN 45 NM EITHER SIDE 
OF THE LINE. A WEAK SURFACE TROUGH EXTENDS FROM 14N77W TO INLAND 
OVER COLOMBIA NEAR CARTAGENA PRODUCING NO SIGNIFICANT WEATHER. A 
SURFACE TROUGH IS JUST E OF THE WINDWARD ISLANDS EXTENDING FROM 
17N57W TO 12N60W GIVING THE WINDWARD ISLANDS ISOLATED SHOWERS 
FROM 11N-14N BETWEEN 60W-63W. 

ATLANTIC OCEAN...
THE SURFACE RIDGE COVERS THE W ATLC W OF 55W INTO THE E GULF OF 
MEXICO ANCHORED BY A 1019 MB HIGH NEAR 27N17W WITH NEAR ZONAL 
WESTERLY FLOW ALOFT AS WELL AS STRONG SUBSIDENCE AND DRY STABLE 
AIR LIMITING ANY SHOWER ACTIVITY. AN UPPER TROUGH COVERS THE 
CENTRAL ATLC N OF 25N BETWEEN 45W-55W SUPPORTING A WEAKENING 
COLD FRONT THAT ENTERS THE CENTRAL ATLC NEAR 32N46W EXTENDING 
ALONG 23N51W TO 17N61W WHERE THE REMNANTS CONTINUE INTO THE NE 
CARIBBEAN. SCATTERED SHOWERS ARE WITHIN 90 NM E OF THE FRONT 
BETWEEN 23N-27N. THE BROAD UPPER RIDGE ANCHORED IN THE W 
TROPICAL ATLC COVERS THE AREA S OF 23N W OF 34W INTO THE 
CARIBBEAN. A SECOND UPPER RIDGE AXIS EXTENDS ALONG 40W FROM 23N 
TO BEYOND 32N ENHANCING THE ACTIVITY ASSOCIATED WITH THE ABOVE 
FRONT. A WEAK SURFACE RIDGE REMAINS OVER THE E/CENTRAL ATLC WITH 
A WEAK 1016 MB HIGH NEAR 24N42W. A SECOND UPPER LEVEL TROUGH IS 
OVER THE E ATLC N OF 22N BETWEEN 30W AND THE COAST OF W AFRICA 
SUPPORTING A SECOND COLD FRONT ENTERING THE E ATLC NEAR 32N17W 
EXTENDING ACROSS THE WESTERN MOST CANARY ISLANDS ALONG 25N22W TO 
23N34W WITH ISOLATED SHOWERS E OF THE FRONT TO THE COAST OF W 
AFRICA N OF 27N ACROSS THE CANARY ISLANDS. A SURFACE TROUGH 
EXTENDS FROM THE MAIN 996 MB LOW CENTERED NEAR 32N22W ALONG 
27N23W TO 25N26W. ISOLATED SHOWERS ARE ASSOCIATED WITH A SURFACE 
LOW COVERING THE AREA N OF 30N BETWEEN 20W-25W. 

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

$$
PAW