000
AXNT20 KNHC 191059
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON JAN 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1015 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N8W ALONG THE EQUATOR BETWEEN 
28W TO 42W THEN S OF THE EQUATOR INTO SOUTH AMERICA NEAR 1S50W. 
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 
150/180 NM S OF THE ITCZ FROM 8W-27W AND FROM 1N TO INLAND OVER 
SW AFRICA E OF 4W TO ACROSS THE PRIME MERIDIAN. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N TO S OF THE 
EQUATOR BETWEEN 30W-35W AND WITHIN 75 NM OF 2N FROM 37W-40W. 
CLUSTERS OF SIMILAR CONVECTION ARE FROM 6N TO INLAND OVER SOUTH 
AMERICA BETWEEN 46W-52W. 

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH REMAIN OVER THE E US SUPPORTING A COLD 
FRONT THAT ENTERS THE GULF JUST W OF JACKSONVILLE FLORIDA 
EXTENDING SW ALONG 26N88W WEAKENING TO NEAR 24N94W. SCATTERED 
SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60 NM OF 
A LINE FROM OVER FLORIDA NEAR DAYTONA BEACH TO TAMPA INTO THE 
GULF TO NEAR 24N91W. A WEAK RIDGE OF HIGH PRESSURE REMAINS SW OF 
THE FRONT BUILDING OVER W TEXAS AND THE NW GULF. ALOFT...WLY  
FLOW DOMINATES THE GULF WITH A JET STREAM OF WINDS FROM 80 TO 
130 KT EXTENDING N OF LINE FROM BROWNSVILLE TEXAS TO W CUBA AND 
INTO THE W ATLC. BAND OF MODERATE SUBSIDENCE AND DRIER STABLE 
AIR IS N OF THE FRONT EXTENDING WITHIN 90/120 NM OF LINE FROM 
TEXAS S OF GALVESTON ALONG 27N88W TO OVER FLORIDA NEAR TAMPA 
LEAVING THE N GULF CLEAR THIS MORNING. 

CARIBBEAN SEA...
BROAD UPPER TROUGH THAT COVERS THE GULF OF MEXICO DIPS S OVER 
THE NW CARIBBEAN COUPLED WITH THE UPPER RIDGE ANCHORED OVER 
SOUTH AMERICA IS GIVING THE CARIBBEAN MOSTLY SW TO W UPPER FLOW. 
MODERATE/STRONG SUBSIDENCE DOMINATES THE ENTIRE AREA. A SURFACE 
TROUGH EXTENDS FROM THE W ATLC ACROSS HAITI TO NEAR 10N77W. 
ISOLATED LOW LEVEL SHOWERS ARE ACROSS HISPANIOLA AND WITHIN 60 
NM OF A LINE FROM 18N72W TO 10N79W. NE SURFACE FLOW IS BANKING 
LOW CLOUDS WITH SCATTERED SHOWERS OVER THE FAR SW CARIBBEAN TO 
INLAND ALONG THE MOUNTAINS FROM W PANAMA THROUGH COSTA RICA TO S 
NICARAGUA AS WELL AS WITHIN 90 NM ALONG THE COASTLINE. THE 
REMAINDER OF THE CARIBBEAN IS TRANQUIL THIS MORNING. 

ATLANTIC OCEAN...
BROAD UPPER LEVEL TROUGH THAT COVERS THE GULF OF MEXICO AND THE 
NW CARIBBEAN COVERS THE W ATLC W OF 60W. THIS UPPER TROUGH 
CONTINUES TO SUPPORT A STATIONARY FRONT THAT ENTERS THE REGION 
NEAR 32N60W EXTENDING SW ALONG 26N66W WHERE IT CONTINUES INTO 
THE CARIBBEAN AS A SURFACE TROUGH ACROSS HAITI. SCATTERED 
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 120/150 
NM ON EITHER SIDE OF THE FRONT N OF 26N. THE COLD FRONT IN THE 
GULF OF MEXICO WILL BE ENTERING THE W ATLC OVER THE NEXT FEW 
HOURS WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS 
TO THE W ATLC N OF 28N W OF 75W. A JET STREAM WITH WINDS OF 80 
TO 130 KT EXTENDS FROM ACROSS THE GULF MEXICO WITHIN 200 NM OF 
LINE FROM 25N80W ALONG 26N72W WEAKENING AND NARROWING TO 80 TO 
90 KT NE TO BEYOND BERMUDA. THE REMAINDER OF THE ATLC IS 
DOMINATED BY BENIGN UPPER FEATURES AND A BROAD SURFACE RIDGE 
THAT COVERS THE AREA N OF 12N E OF THE FRONT/SURFACE TROUGH IN 
THE W ATLC ANCHORED BY A 1034 MB HIGH NEAR 31N32W GIVING THE 
AREA FAIR WEATHER CLOUDS ACROSS THE REMAINDER OF THE REGION THIS 
MORNING. 

$$
WALLACE