000
AXNT20 KNHC 091754
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI NOV 09 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1645 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO THE COAST OF 
GUINEA-BISSAU AT 12N16W TO 10N20W WHERE THE ITCZ PICKS UP AND 
CONTINUES ALONG 10N31W 8N42W 8N51W 9N61W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM EITHER SIDE 
OF THE AXIS BETWEEN 20W-48W. 
 
...DISCUSSION...

THE GULF OF MEXICO...
FAIR WEATHER CONTINUES TO COVER THE GULF OF MEXICO TODAY DUE TO 
THE COMBINATION OF SURFACE RIDGING ACROSS THE BASIN AND DRY AIR 
ALOFT AROUND AN UPPER LEVEL RIDGE COVERING MEXICO AND THE 
CENTRAL/EASTERN CONUS. LIGHT ANTI-CYCLONIC FLOW IS ACROSS THE 
BASIN WITH STRONGER RETURN FLOW UP TO 15-20 KT ACROSS THE TEXAS 
COAST. SURFACE RIDGING WILL REMAIN ACROSS THE BASIN WITH FAIR 
WEATHER CONTINUING. THE 15-20 KT WINDS ARE EXPECTED TO SPREAD 
EASTWARD ACROSS THE REST OF THE BASIN WITHIN 24 HOURS. 

THE CARIBBEAN SEA...
DRY AIR ALOFT COVERS THE NW CARIBBEAN SINKING SOUTH AROUND THE 
BASE OF AN UPPER LEVEL TROUGH ACROSS THE WEST ATLC KEEPING THIS 
AREA UNDER MOSTLY CLEAR SKIES. THE UPPER TROUGH SUPPORTS A COLD 
FRONT THAT EXTENDS FROM THE W ATLC TO WESTERN HISPANIOLA 
TRANSITIONING INTO A SHEAR AXIS FROM THE WEST COAST OF HAITI AT 
19N74W TOWARDS HONDURAS TO 17N81W...AND THEN WRAPPING SOUTH TO 
14N83W. STRONG NE WINDS ARE NORTH AND WEST OF THE SHEAR AXIS UP 
TO 20-25 KT WITH SLIGHTLY LIGHTER NORTHEAST WINDS SOUTH OF THE 
AXIS OF 15-20 KT. POSSIBLE ISOLATED SHOWERS ARE WITHIN 75 NM 
EITHER SIDE OF THE AXIS. A FEW SHOWERS/THUNDERSTORMS ARE FARTHER 
SOUTH ACROSS PORTIONS OF COAST RICA AND PANAMA ASSOCIATED WITH 
THE MONSOON TROUGH THAT EXTENDS FROM SOUTHERN COSTA RICA TO 
NORTHERN COLOMBIA. DRY AIR ALOFT CONTINUES TO SPREAD EASTWARD 
ACROSS THE CENTRAL AND EASTERN CARIBBEAN IN MOSTLY WESTERLY FLOW 
ALOFT HELPING PROVIDE FAIR CONDITIONS ACROSS THESE AREAS. 
TRADEWIND FLOW OF 10-15 KT IS PRESENT ACROSS THE EASTERN 
CARIBBEAN. EXPECT NE WINDS OF 15-20 KT TO REMAIN ACROSS THE  
WESTERN HALF OF THE BASIN AS SURFACE RIDGING BUILDS TO THE 
NORTH. 

THE ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH COVERS THE WEST ATLC WEST OF 55W 
SUPPORTING A COLD FRONT THAT HAS BEEN MOVING THROUGH THE AREA 
OVER THE PAST SEVERAL DAYS AND CURRENTLY EXTENDS FROM 32N59W 
ALONG 25N63W TO HISPANIOLA AT 20N71W. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE WITHIN 90 NM TO EITHER SIDE OF THE AXIS. DRY 
AIR ALOFT AROUND THE BASE OF THE UPPER TROUGH IS HELPING KEEP 
THE REMAINDER OF THE WEST ATLC UNDER FAIR CONDITIONS. AN UPPER 
LEVEL RIDGE COVERS THE CENTRAL ATLC ALONG 52W EXTENDING INTO A 
LARGER UPPER RIDGE OVER THE NE ATLC SUPPORTING A BROAD SURFACE 
RIDGE ANCHORED BY A 1033 MB AZORES HIGH. THE RIDGE IS PROVIDING 
GENERALLY FAIR CONDITIONS ACROSS THE EASTERN ATLC EXCEPT FOR AN 
AREA OF DISTURBED WEATHER NW OF THE CAPE VERDE ISLANDS. AN UPPER 
LEVEL TROUGH IS SOUTH OF THE LARGE UPPER RIDGE ALONG 38W 
SUPPORTING A SURFACE TROUGH ALONG 23N34W TO 17N38W. SCATTERED 
SHOWERS/THUNDERSTORMS ARE EAST OF THE TROUGH FROM 16N-23N 
BETWEEN 28W-36W. AN ASCAT PASS FROM EARLIER THIS MORNING ALSO 
INDICATES THAT WINDS UP TO 30 KT ARE EAST OF THE TROUGH AXIS. 

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

$$
WALTON