000
AXNT20 KNHC 212338
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST SAT NOV 21 2009

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...

THE ITCZ AXIS IS CENTERED ALONG 8N12W 6N20W 6N40W 8N48W 6N57W. 
WIDELY SCATTERED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 
23W-30W...FROM 2N-4N BETWEEN 32W-35W...AND FROM 6N-8N BETWEEN 
38W-41W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ FROM 
14N45W TO 5N49W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE 
TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A 1006 MB LOW IS CENTERED OFF THE COAST OF 
LOUISIANA NEAR 29N92W. A WARM FRONT EXTENDS E FROM THE LOW TO 
THE FLORIDA PANHANDLE NEAR 30N84W. A COLD FRONT ALSO EXTENDS S 
FROM THE LOW CENTER TO THE BAY OF CAMPECHE ALONG 27N90W 19N95W. 
20-25 KT WINDS ARE NOTED OVER THE NW GULF OF MEXICO IN VICINITY 
OF THE LOW. WIDELY SCATTERED MODERATE CONVECTION IS IN THE WARM 
SECTOR FROM 25N-29N BETWEEN 85W-90W. SCATTERED SHOWERS ARE NOTED 
FURTHER N ON RADAR FROM 29N-33N BETWEEN 85W-94W. IN THE UPPER 
LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER E TEXAS NEAR 
31N94W. CYCLONIC FLOW IS N OF 26N. THE REMAINDER OF THE GULF HAS 
SW UPPER LEVEL FLOW. A DRY SLOT HAS WRAPPED AROUND THE WESTERN 
AND SOUTHERN PORTIONS OF THE UPPER LEVEL LOW WITH SIGNIFICANT 
UPPER LEVEL MOISTURE ELSEWHERE OVER THE GULF. EXPECT THE SURFACE 
LOW TO MOVE TO S ALABAMA IN 24 HOURS WITH A TRAILING COLD FRONT 
EXTENDING S TO THE YUCATAN PENINSULA AND A WARM FRONT OVER 
GEORGIA. EXPECT 15-20 KT N WINDS W OF THE COLD FRONT AND 10 KT S 
WINDS E OF THE COLD FRONT. ALSO EXPECT CONVECTION TO BE ALONG 
THE COLD FRONT OVER THE GULF. 

CARIBBEAN SEA...
MODERATE TO FRESH TRADEWINDS DOMINATES THE BASIN. A 1005 MB LOW 
IS CENTERED INLAND OVER N COLOMBIA NEAR 8N75W. ISOLATED MODERATE 
CONVECTION IS FROM 4N-10N BETWEEN 74W-81W. PATCHES OF BROKEN TO 
OVERCAST LOW CLOUDS DOTS THE CARIBBEAN AND CENTRAL AMERICA 
NAMELY OVER PUERTO RICO...HISPANIOLA...W CUBA...E HONDURAS AND 
THE NW CARIBBEAN FROM 14N-18N BETWEEN 82W-87W. SIMILAR SHOWERS 
ARE OVER COSTA RICA...PANAMA...AND THE SW CARIBBEAN S OF 11N W 
OF 81W. IN THE UPPER LEVELS...A BROAD RIDGE WITH RIDGE AXIS 
ALONG 75W IS OVER THE ENTIRE CARIBBEAN. DRY AIR AND 
SUBSIDENCE COVERS THE ENTIRE AREA WITH UPPER LEVEL MOISTURE 
REMAINING ONLY OVER N COLOMBIA. EXPECT...SHOWERS/THUNDERSTORMS 
TO CONTINUE OVER THE SW CARIBBEAN OVER THE NEXT 24 HOURS. ALSO 
EXPECT...SIMILAR CONVECTION OVER E CUBA. 

ATLANTIC OCEAN...
A SURFACE TROUGH IS OVER THE W ATLANTIC FROM 29N71W TO THE 
CENTRAL BAHAMAS NEAR 24N76W. SCATTERED SHOWERS ARE WITHIN 120 NM 
OF THE TROUGH AXIS. A WEAK 1018 MB LOW IS OVER THE CENTRAL 
ATLANTIC NEAR 27N50W. ISOLATED MODERATE CONVECTION IS FROM 
23N-31N BETWEEN 43W-50W. A LONG STATIONARY FRONT IS OVER THE 
ATLANTIC ALONG 32N16W 28N30W 27N40W 29N48W. SCATTERED SHOWERS 
ARE WITHIN 90 NM OF THE FRONT. EXPECT...MORE CONVECTION OVER THE 
CENTRAL ATLANTIC FROM 24N-32N BETWEEN 45W-55W DUE TO THE CENTRAL 
ATLANTIC LOW OVER THE NEXT 24 HOURS.  

$$
FORMOSA