000
AXNT20 KNHC 050533
TWDAT 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED NOV 05 2008

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.

...SPECIAL FEATURE...
A BROAD AREA OF LOW PRESSURE OVER THE SW CARIBBEAN SEA IS 
DRIFTING NORTH-NORTHWESTWARD. A SURFACE TROUGH EXTENDS FROM N OF 
PANAMA NEAR 9N81W TO A 1008 MB SURFACE LOW E OF THE COAST OF 
NICARAGUA NEAR 14N82W TO E CUBA NEAR 21N78W. LOW LEVEL 
CONVERGENCE NEAR THE LOW AND TROUGH...COMBINED WITH DEEP 
MOISTURE AND UPPER LEVEL DIVERGENCE OVER THE W CARIBBEAN...IS 
SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS FROM 11N-21N 
BETWEEN 74W-84W. THIS SYSTEM CONTINUES TO SHOW SOME SIGNS OF 
ORGANIZATION...AND COULD BECOME A TROPICAL DEPRESSION DURING THE 
NEXT DAY OR TWO AS IT CONTINUES MOVING SLOWLY TO THE 
NORTH-NORTHWEST OR NORTH.

...THE ITCZ...
ITCZ AXIS IS ANALYZED ALONG 8N13W 6N20W 5N32W 6N38W 1N51W. 
SCATTERED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF 
THE ITCZ AXIS BETWEEN 20W-29W...WHICH IS BEING ENHANCED BY WEAK 
UPPER LEVEL DIVERGENCE. SCATTERED MODERATE CONVECTION IS FROM 
2N-9N BETWEEN 30W-39W...WHICH IS BEING ENHANCED BY STRONG UPPER 
LEVEL DIVERGENCE.  

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH OVER THE E CONUS EXTENDS INTO THE GULF. 
DEEP LAYER SUBSIDENCE COVERS THE NW GULF...WHERE NORTHWESTERLY 
FLOW ALOFT IS IN PLACE. ADDITIONALLY...SUBSIDENCE IS OCCURRING 
IN ASSOCIATION WITH A SURFACE RIDGE OF HIGH PRESSURE OVER THE SE 
CONUS THAT EXTENDS INTO THE GULF. ALSO...DEEP LAYER DRY AIR IS 
CIRCULATING CYCLONICALLY AROUND THE BASE OF THE UPPER TROUGH 
ACROSS MUCH OF THE GULF. THE COMBINATION OF THE SUBSIDENCE AND 
DEEP LAYER DRY AIR IS MAINTAINING GENERALLY FAIR WEATHER 
CONDITIONS ACROSS THE GULF REGION.

CARIBBEAN SEA...
AN UPPER LEVEL HIGH IS OVER THE E CARIBBEAN NEAR 17N72W...WITH 
THE ANTICYCLONIC FLOW AROUND THE HIGH COVERING MUCH OF THE 
CARIBBEAN. DEEP MOISTURE AND UPPER LEVEL DIVERGENCE W OF THE 
HIGH...AS WELL AS LOW LEVEL CONVERGENCE AROUND A SURFACE LOW AND 
SURFACE TROUGH IN THE W CARIBBEAN...ARE SUPPORTING SHOWERS AND 
THUNDERSTORMS OVER THE W CARIBBEAN. PLEASE SEE THE SPECIAL 
FEATURE SECTION ABOVE FOR MORE INFORMATION ON THIS SYSTEM. DEEP 
LAYER DRY AIR E OF THE UPPER HIGH IS RESULTING IN GENERALLY FAIR 
WEATHER CONDITIONS ACROSS THE E CARIBBEAN. ALSO...DEEP LAYER DRY 
AIR OVER THE GULF OF MEXICO IS MOVING INTO THE FAR NW CARIBBEAN. 

ATLANTIC OCEAN...
STRONG WEST-SOUTHWESTERLY FLOW ALOFT E OF AN UPPER TROUGH AXIS 
OVER THE E CONUS IS ENHANCING UPPER LEVEL DIVERGENCE AND DEEP 
ATMOSPHERIC LIFT OVER PORTIONS OF THE W ATLC. ALSO...A 1008 MB 
SURFACE LOW IS CENTERED E OF FLORIDA NEAR 31N75W. TO THE S OF 
THE LOW...A COLD FRONT EXTENDS FROM 31N75W TO 26N73W TO 22N73W. 
TO THE E OF THE LOW...A WARM FRONT EXTENDS FROM 31N75W TO 31N70W 
TO 31N66W. TO THE N OF THE LOW...A SURFACE TROUGH EXTENDS FROM 
31N74W TO 32N75W TO NW OF THE DISCUSSION AREA. LOW LEVEL 
CONVERGENCE IS FURTHER ENHANCING THE DEEP ATMOSPHERIC LIFT NEAR 
THE SURFACE FRONTS...TROUGH...AND LOW...WHERE DEEP MOISTURE IS 
MOVING NORTHEASTWARD FROM THE W CARIBBEAN. AS A RESULT... 
ISOLATED MODERATE CONVECTION IS N OF 23N BETWEEN 58W-74W. 
FARTHER TO THE E...AN UPPER LEVEL TROUGH IS PRESENT WITH AN AXIS 
THAT EXTENDS FROM 3N44W TO 15N40W TO 32N44W TO NW OF THE 
DISCUSSION AREA. THIS UPPER TROUGH IS ACCOMPANIED BY TWO SURFACE 
TROUGHS. ONE SURFACE TROUGH EXTENDS FROM 10N48W TO 15N48W TO 
21N46W...WITH ISOLATED MODERATE CONVECTION FROM 13N-21N BETWEEN 
39W-48W. THE SECOND SURFACE TROUGH EXTENDS FROM 26N44W TO 29N41W 
TO 32N38W...WITH ISOLATED MODERATE CONVECTION N OF 27N BETWEEN 
34W-42W...WHICH IS BEING ENHANCED BY A COLD FRONT THAT EXTENDS 
FROM 31N45W TO 32N42W TO NE OF THE DISCUSSION AREA. ALSO...AN 
UPPER RIDGE IS PRESENT WITH AN AXIS THAT EXTENDS FROM 16N16W TO 
19N21W TO 27N25W...WITH ASSOCIATED UPPER LEVEL DIVERGENCE S OF 
THE RIDGE AXIS ENHANCING THE CONVECTION IN THE VICINITY OF THE 
ITCZ AXIS.
  
$$
COHEN