000
AXNT20 KNHC 200530
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST SAT NOV 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...THE ITCZ...
 
ITCZ AXIS IS ANALYZED ALONG 11N15W 4N31W 6N39W 2N51W. A SURFACE 
TROUGH IS EMBEDDED WITHIN THE ITCZ FROM 10N38W TO 1N40W. 
SCATTERED STRONG CONVECTION IS N OF THE ITCZ AND S OF A LINE 
FROM 7N24W TO 8N32W WITH CLUSTERS OF SIMILAR CONVECTION FROM 
1N-8N BETWEEN 31W-41W. CLUSTERS OF SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION ARE WITHIN 150 NM S OF THE ITCZ FROM 20W-31W 
AND FROM 5N-11N BETWEEN 37W-48W. 

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE ANCHORED IN THE CARIBBEAN COVERS THE AREA 
GIVING THE ENTIRE GULF SW TO W FLOW ALOFT WITH MODERATE 
SUBSIDENCE AND MOSTLY DRY STABLE AIR ALOFT AS NOTED IN WATER 
VAPOR IMAGERY. A BROAD SURFACE RIDGE DOMINATES THE GULF WITH A 
WEAKNESS IN THE VICINITY OF A SURFACE TROUGH THAT EXTENDS FROM A 
WEAK 1021 MB LOW JUST E OF LAKE PONTCHARTRAIN LOUISIANA ALONG 
28N87W TO 25N89W. ISOLATED SHOWERS ARE WITHIN 60 NM E OF THE 
SURFACE TROUGH. ISOLATED SHOWERS ARE ALSO W OF A SECOND EQUALLY 
WEAK SURFACE TROUGH OVER THE SW GULF THAT EXTENDING ALONG 95W S 
OF 22N INTO THE W BAY OF CAMPECHE LEAVING THE REMAINDER OF THE 
GULF WITH FAIR CONDITIONS TONIGHT. 

CARIBBEAN SEA...
A WEAKENING STATIONARY FRONT EXTENDS ACROSS CENTRAL CUBA NW OF 
CAMAGUEY ALONG 20N84W TO THE GULF OF HONDURAS NEAR 16N87W WITH 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 19N W OF THE FRONT 
TO INLAND OVER THE YUCATAN AND ISOLATED SHOWERS WITHIN 180 NM 
BOTH SIDES THE REMAINDER OF THE FRONT. A SURFACE TROUGH IS OVER 
THE E CARIBBEAN EXTENDING FROM 16N64W TO JUST OFF THE COAST OF 
VENEZUELA NEAR 11N66W WITH SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS FROM 13N-17N E OF 67W TO OVER THE LESSER 
ANTILLES. BROAD UPPER RIDGE COVERS THE ENTIRE CARIBBEAN AND 
EXTENDING OVER THE GULF OF MEXICO ANCHORED S OF HAITI NEAR 
17N72W. THIS UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO 
ENHANCE THE ACTIVITY ASSOCIATED WITH THE ABOVE SURFACE TROUGH 
AND GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 
12N-15N BETWEEN 68W-76W INCLUDING THE ABC ISLANDS. ISOLATED 
SHOWERS ARE ALSO IN THE SW CARIBBEAN S OF A LINE FROM NEAR 
CARTAGENA COLOMBIA TO LAGUNA DE PERLAS NICARAGUA. 

ATLANTIC OCEAN...
BROAD UPPER LEVEL TROUGH COVERS THE W ATLC N OF 23N W OF 50W 
SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N54W 
EXTENDING SW ALONG 26N63W THROUGH THE S BAHAMA ISLANDS NEAR 
24N74W BECOMING STATIONARY ACROSS CENTRAL CUBA NW OF CAMAGUEY 
INTO THE W CARIBBEAN. SCATTERED SHOWERS ARE WITHIN 120/150 NM SE 
OF THE FRONT. A WEAKENING CUT-OFF UPPER LOW IS OVER THE 
E/CENTRAL ATLC CENTERED NEAR 25N40W WITH NO SURFACE REFLECTIONS. 
A HIGH AMPLITUDE UPPER RIDGE IS JUST TO THE E EXTENDING FROM THE 
TROPICS NEAR 9N28W TO BEYOND 32N22W PROVIDING DIFFLUENCE ALOFT 
TO ENHANCE SCATTERED SHOWERS WITHIN 200 NM ON OF LINE FROM 
17N31W TO 30N27W. A SURFACE RIDGE COVERS THE E ATLC N OF 20N E 
OF 35W ANCHORED BY A 1021 MB HIGH W OF THE CANARY ISLANDS NEAR 
30N21W. 

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

$$
PAW