000
AXNT20 KNHC 291731
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST WED DEC 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

...THE ITCZ...

ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 9N13W 
WESTWARD ALONG 6N20W 4N30W 3N40W 3N46W EQ50W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 80 NM 
ON EITHER SIDE OF THE ITCZ BETWEEN 13W-25W. SIMILAR CONVECTION 
IS BETWEEN 33W-48W.    

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES SW FLOW ALOFT ACROSS THE 
BASIN...WITH AN UPPER LEVEL SHORTWAVE MOVING OFF THE SOUTH TEXAS 
COAST. THIS FEATURE IS ENHANCING SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS ALONG THE COAST OF EASTERN TEXAS/WESTERN 
LOUISIANA BETWEEN 92W AND 96W. AT SURFACE...SURFACE RIDGE 
REMAINS IN CONTROL OF THE GULF THIS AFTERNOON...ANCHORED BY A 
1025 MB HIGH OVER NORTHERN FLORIDA NEAR 29N82W. 10-10 KT S-SE 
FLOW IS OBSERVED ACROSS MOST OF THE AREA. RETURN FLOW CONTINUES 
TO BANK LOW CLOUDS AND ISOLATED SHOWERS OVER THE FAR WESTERN 
GULF W OF 93W. BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVER THE 
SE GULF S OF 26N BETWEEN 82W AND 89W. THE SURFACE RIDGE IS 
EXPECTED TO CONTINUE TO SHIFT SLOWLY EASTWARD WITH THE NEXT COLD 
FRONT ENTERING THE GULF LATE THU/EARLY FRI.  

CARIBBEAN SEA...
DRY WSW FLOW ALOFT IS NOTED ACROSS MUCH OF THE BASIN THIS 
AFTERNOON. THE SURFACE RIDGE OVER THE GULF OF MEXICO AND W ATLC 
COVERS THE NW CARIBBEAN WITH BROKEN TO OVERCAST STRATOCUMULUS 
CLOUDS N OF 15N W OF 80W. A DISSIPATING STATIONARY FRONT EXTENDS 
FROM THE CENTRAL ATLC ACROSS THE LEEWARD ISLANDS NEAR ANTIGUA 
AND BARBUDA TO 15N69W. BROKEN/OVERCAST LOW/MID CLOUDS WITH 
ISOLATED SHOWERS ARE WITHIN 90 NM W OF THE FRONT TO ACROSS THE 
US/UK VIRGIN ISLANDS AND PUERTO RICO. THIS FRONT WILL CONTINUE 
TO DISSIPATE OVER THE NEXT 24 HOURS WITH SHOWERS LINGERING 
ACROSS THE FAR NE CARIBBEAN UP TO 36 HOURS. AN AREA OF LOW LEVEL 
CONFLUENCE IS FOUND IN THE SW BASIN BETWEEN NE WINDS AND TRADE 
WINDS...PRODUCING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 
WITHIN 60 NM OF A LINE EXTENDING FROM 18N74W TO 14N83W. COMPUTER 
MODELS SUGGEST THIS AREA OF CONVECTION WILL PERSIST OVER THE 
NEXT 24 HOURS.

ATLANTIC OCEAN...
BROAD UPPER TROUGH COVERS THE N CENTRAL ATLC SUPPORTING A COLD 
FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N38W ALONG 23N50W 
BECOMING A STATIONARY FRONT ACROSS THE LEEWARD ISLANDS NEAR  
17N62W WHERE IT DISSIPATES INTO THE CARIBBEAN. SCATTERED SHOWERS 
ARE WITHIN 100 NM EAST OF THE FRONT N OF 22N. ISOLATED SHOWERS 
ARE WITHIN 90 NM W OF THE STATIONARY FRONT. BROKEN TO OVERCAST 
COLD AIR STRATOCUMULUS CLOUDS COVER THE REST OF THE WEST ATLC W 
OF THE FRONT N OF 20N...WITH SKIES BEGINNING TO CLEAR N OF 26N W 
OF 73W...DUE TO AN UPPER LEVEL RIDGE MOVING INTO THE WEST ATLC 
ANCHORED BY A 1025 MB HIGH OVER NORTHERN FLORIDA NEAR 29N82W. A 
SURFACE RIDGE COVERS THE REMAINDER OF THE EASTERN ATLC ANCHORED 
BY A 1018 MB HIGH NEAR 26N34W. AN UPPER LEVEL TROUGH REMAINS IN 
THE FAR EASTERN ATLC SUPPORTING A WEAK SURFACE TROUGHING N OF 
27N BETWEEN 11W AND 18W. AS HIGH PRESSURE WEATHER SETTLES ACROSS 
THE WESTERN ATLC...LOOK FOR THE CENTRAL ATLC FRONT TO CONTINUES 
TO MOVE EASTWARD WITH CONVECTION. 

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

$$

GARCIA