000
AXNT20 KNHC 041759
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST TUE JAN 04 2011

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.

...ITCZ...

ITCZ AXIS IS ANALYZED FROM SIERRA LEONE NEAR 7N12W ALONG 3N20W 
2N30W 1N40W CROSSING THE EQUATOR NEAR 43W TO NE BRAZIL NEAR 
1S45W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
ARE FROM THE EQUATOR TO 6N BETWEEN 16W AND 30W. 

...DISCUSSION...

GULF OF MEXICO...
THE UPPER LEVELS OF THE GULF ARE DOMINATED BY THE UPPER RIDGE 
THAT COVERS THE CARIBBEAN GIVING THE GULF SW TO W FLOW ALOFT. A 
SURFACE RIDGE COVERS THE GULF INTO THE W ATLC ANCHORED BY TWO 
1023 MB HIGHS OFF THE NORTH CAROLINA COAST AND OVER S ALABAMA 
GIVING THE GULF E TO SE SURFACE FLOW. A SURFACE LOW OVER DEEP 
SOUTH TEXAS HAS A FRONTAL BOUNDARY MEANDERING AROUND 28N 
EXTENDING BETWEEN THE TEXAS COAST TO 89W. A BURST OF MODERATE 
CONVECTION WITH THUNDERSTORMS IS ALONG 87W FROM 27N-29N. BROKEN 
TO OVERCAST LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE 
N OF 25N AND ALSO ALONG THE COAST OF MEXICO W OF 95W LEAVING THE 
REMAINDER OF THE S GULF UNDER CLEAR SKIES THIS AFTERNOON. EXPECT 
THE SURFACE LOW TO MOVE NE WITH FRONT IN THE GULF TO BECOME MORE 
STATIONARY AS THE NEXT FRONTAL SYSTEM MOVES SE TOWARDS THE GULF 
OVER THE NEXT 24 HOURS. 

CARIBBEAN SEA...
THE UPPER LEVELS OF THE CARIBBEAN ARE DOMINATED BY A BROAD UPPER 
RIDGE ANCHORED OVER SOUTH AMERICA WITH MODERATE/STRONG 
SUBSIDENCE AND DRY STABLE AIR ALOFT. A SURFACE TROUGH IS OVER 
THE E CARIBBEAN EXTENDING FROM THE COAST OF VENEZUELA NEAR 
11N69W TO 16N64W. THE AREA SE OF THE SURFACE TROUGH IS UNDER 
RELATIVELY CLEAR SKIES. BROKEN/OVERCAST LOW CLOUDS ARE WITHIN 
190 NM NW OF THE TROUGH AXIS. SIMILAR CLOUDS ARE MOVING WSW S OF 
16N. THE REMAINDER OF THE CARIBBEAN IS UNDER FAIR WEATHER. 

ATLANTIC OCEAN...
A BROAD UPPER TROUGH IS MOVING OVER THE NW ATLC SUPPORTING A 
COLD FRONT THAT ENTERS THE REGION NEAR 32N50W ALONG 28N60W TO 
27N70W WHERE IT BECOMES A STATIONARY FRONT TO 25N78W. DENSE LOW 
LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE WITHIN 90 NM SE 
OF THE COLD FRONT. THE BROAD UPPER RIDGE THAT COVERS THE 
CARIBBEAN ALSO COVERS THE W AND CENTRAL ATLC S OF 30N W OF 42W 
AND A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH OFF THE COAST OF 
NORTH CAROLINA IS RIDGING ACROSS THE ABOVE FRONT. AN UPPER 
TROUGH IS OVER THE CENTRAL/E ATLC SUPPORTING A COLD FRONT THAT 
EXTENDS ALONG 32N28W 27N35W TO 23N45W. A PRE-FRONTAL TROUGH 
EXTENDS FROM 30N27W TO 24N36W. AN BROAD UPPER RIDGE DOMINATES 
THE EASTERN ATLANTIC ALONG THE WEST AFRICAN COAST. 

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

$$
MONTALVO/HUFFMAN