000
AXNT20 KNHC 182348
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU OCT 18 2012

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
2315 UTC.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE EXTENDS IS ALONG 46W TO THE 
SOUTH OF 19N MOVING WESTWARD AT 15 KNOTS. SCATTERED MODERATE 
CONVECTION IS FROM 9N-13N BETWEEN 46W-50W. SCATTERED SHOWERS ARE 
ELSEWHERE FROM 8N-18N BETWEEN 43W-50W. 

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

THE MONSOON TROUGH EXTENDS FROM COASTAL GUINEA-BISSAU NEAR 
12N16W TO 7N31W. THE ITCZ CONTINUES FROM 7N31W TO 7N40W TO 
12N47W TO 10N62W. ISOLATED MODERATE CONVECTION IS S OF THE 
MONSOON TROUGH ALONG THE COAST OF WEST AFRICA FROM 5N-10N 
BETWEEN 13W-19W. ISOLATED MODERATE CONVECTION IS S OF THE ITCZ 
FROM 7N-10N BETWEEN 51W-54W.  

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC... A COLD FRONT EXTENDS FROM THE FLORIDA 
PANHANDLE AT 31N86W TO THE NORTH CENTRAL GULF OF MEXICO AT 
28N90W TO THE S TEXAS COAST AT 27N97W. RADAR IMAGERY SHOWS 
SHOWERS AND THUNDERSTORMS OVER THE NE GULF...E OF THE FRONT... 
FROM 29N-31N BETWEEN 84W-87W. THUNDERSTORMS ARE ALSO OVER S 
TEXAS FROM 26N-27N BETWEEN 96W-98W. ELSEWHERE...A 1009 MB LOW IS 
CENTERED OVER THE SE GULF NEAR 25N83W. SCATTERED SHOWERS ARE 
OVER THE SE GULF AND THE STRAITS OF FLORIDA FROM 23N-25N BETWEEN 
80W-83W. THE REMAINDER OF THE GULF HAS MOSTLY FAIR WEATHER. IN 
THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER MEXICO 
AT 18N100W. RIDGING IS OVER THE W GULF W OF 90W. THE BASE OF AN 
UPPER LEVEL TROUGH IS OVER FLORIDA AND THE E GULF. CONSIDERABLE 
UPPER LEVEL MOISTURE AND BROKEN HIGH CLOUDS ARE OVER THE NE GULF 
AND N FLORIDA...AND THE STRAITS OF FLORIDA AND S FLORIDA.   
EXPECT IN 24 HOURS...FOR THE COLD FRONT TO EXTEND FROM TAMPA 
FLORIDA TO BROWNSVILLE TEXAS WITH CONVECTION PREVALENT OVER NE 
MEXICO. 

CARIBBEAN SEA...
A RELATIVELY LAX SURFACE PRESSURE GRADIENT IS OVER THE CARIBBEAN 
SEA AND CENTRAL AMERICA PRODUCING PREDOMINATELY 10 KT WINDS. THE 
TRADEWINDS HAVE RETURNED TO THE E CARIBBEAN E OF 75W. A SURFACE 
TROUGH IS OVER THE SW CARIBBEAN SEA FROM 17N79W TO THE COAST OF 
PANAMA AT 10N80W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 
7N-13N BETWEEN 77W-83W. FURTHER E... WIDELY SCATTERED MODERATE 
CONVECTION IS OVER THE E CARIBBEAN E OF 77W. A SURFACE TROUGH IS 
ALSO OVER THE E CARIBBEAN FROM 16N63W TO 10N65W MOVING W AND 
ENHANCING CONVECTION. IN THE UPPER LEVELS...AN UPPER LEVEL 
TROUGH IS OVER THE NW CARIBBEAN W OF 80W. AN UPPER LEVEL HIGH IS 
CENTERED OVER THE CENTRAL CARIBBEAN NEAR 15N74W. CONSIDERABLE 
UPPER LEVEL MOISTURE AND BROKEN HIGH CLOUDS ARE OVER THE E 
CARIBBEAN E 80W. EXPECT SHOWERS AND CONVECTION TO BE PREVALENT 
OVER MOST OF THE CARIBBEAN OVER THE NEXT 24 HOURS.    
 
ATLANTIC OCEAN...
WIDELY SCATTERED MODERATE CONVECTION IS OVER THE BAHAMAS AND THE 
W ATLANTIC FROM 24N-30N BETWEEN 74W-80W. A SURFACE TROUGH IS 
FURTHER E FROM 31N55W TO 23N66W. WIDELY SCATTERED MODERATE 
CONVECTION IS WITHIN 180 NM E OF THE TROUGH AXIS N OF 26N. A 
LARGE 1025 MB HIGH IS CENTERED OVER THE CENTRAL ATLANTIC NEAR 
34N36W PRODUCING FAIR WEATHER.   

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

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FORMOSA