000
AXNT20 KNHC 222351
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST TUE NOV 22 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...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 2345 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS WRN AFRICA THROUGH GUINEA 
ENTERING THE ATLC WATERS ALONG 10N14W TO 7N17W. THE ITCZ AXIS 
EXTENDS FROM 7N17W ALONG 5N28W TO 5N41W...THEN IT RESUMES W OF A 
SURFACE TROUGH NEAR 5N45W TO SOUTH AMERICA NEAR 4N53W. THE 
EMBEDDED SURFACE TROUGH IS ANALYZED FROM 12N42W TO 4N44W. 
SCATTERED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF 
THE ITCZ BETWEEN 20W-41W. SIMILAR CONVECTION IS WITHIN 40 NM 
EITHER SIDE OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH IS MOVING 
NEAR THE COASTAL WATERS OF GUYANA...ANALYZED FROM 12N55W TO 
6N57W. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE 
OF THE TROUGH AXIS N OF 9N. 

...DISCUSSION...

THE GULF OF MEXICO...
A COLD FRONT ENTERED THE NW BASIN THIS LATE AFTERNOON. THIS 
BOUNDARY IS CURRENTLY ANALYZED FROM THE WRN LOUISIANA COAST TO 
THE SRN TEXAS COAST ALONG 29N93W TO 26N97W. DOPPLER RADAR 
IMAGERY INDICATED HEAVY SHOWERS AND THUNDERSTORMS AHEAD OF THE 
BOUNDARY WITHIN 60 NM. SURFACE SOUTHERLY FLOW UP TO 15 KT IS 
ELSEWHERE ACROSS THE REMAINDER OF THE GULF...WITH ONLY A FEW 
LINES OF SHOWERS DEVELOPING OVER THE NE BASIN N OF 26N E OF 88W. 
THE SOUTHERLY FLOW IS PROVIDED BY A SURFACE RIDGE CENTERED OVER 
THE WRN ATLANTIC. STRONG SUBSIDENCE COVERS THE GULF IN THE UPPER 
LEVELS OF THE ATMOSPHERE. EXPECT THE COLD FRONT TO EXTEND FROM 
THE FLORIDA PANHANDLE TO TAMPICO MEXICO IN 24 HOURS WITH 
CONVECTION. ALSO EXPECT 20-25 KT N WINDS OVER THE NW GULF BEHIND 
THE FRONT.   

THE CARIBBEAN SEA...
A SURFACE TROUGH EXTENDS FROM THE CENTRAL CARIBBEAN SEA NEAR 
15N74W INTO NRN COLOMBIA NEAR 10N74W. SCATTERED SHOWERS ARE 
MOSTLY N OF 13N WITHIN 70 NM ALONG THE AXIS AND THEY ARE QUICKLY 
MOVING INTO THE SW BASIN WITH THE 10-25 KT TRADEWINDS. THE 
MONSOON TROUGH EXTENDS INLAND ACROSS CENTRAL AMERICA ALONG COSTA 
RICA...PANAMA...INTO NRN COLOMBIA. SCATTERED WEAK SHOWERS ARE IN 
THE VICINITY OF THE MONSOON TROUGH AFFECTING MOSTLY THE COASTAL 
WATERS OF COSTA RICA. IN THE UPPER LEVELS...THE BASE OF AN UPPER 
LEVEL TROUGH IS OVER THE CENTRAL/WRN CARIBBEAN SEA WITH STRONG 
SUBSIDENCE EVERYWHERE BUT THE FAR SE. EXPECT THE SURFACE TROUGH 
TO MOVE W WITH SHOWERS OVER THE NEXT 24 HOURS. 

THE ATLANTIC OCEAN...
A WEAKENING 1022 MB HIGH IS CENTERED OVER THE W ATLANTIC NEAR 
30N72W PROVIDING FAIR WEATHER CONDITIONS TO MOST OF THE WRN 
ATLC. A 1004 MB GALE LOW IS CENTERED OVER THE CENTRAL ATLANTIC 
NEAR 30N45W MOVING NE OUT OF OUR DISCUSSION AREA. A COLD FRONT 
EXTENDS S FROM THE OCCLUSION POINT N OF THE LOW INTO OUR AREA 
ALONG 30N43W AND CONTINUES SW ALONG 24N46W TO 20N54W. SCATTERED 
SHOWERS AREA WITHIN 150 NM AHEAD OF THE FRONT. GALE FORCE WINDS 
ARE WITHIN 270 NM SE AND 150 NM SW QUADRANT GENERATING SEAS 11 
TO 14 FT. A LARGE 1033 MB HIGH IS CENTERED OVER THE NE ATLANTIC 
NEAR 40N20W EXTENDING A RIDGE AXIS SSW 17N45W...KEEPING FAIR 
WEATHER CONDITIONS ELSEWHERE E OF 40W. 

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

$$

GARCIA