000
AXNT20 KNHC 181132
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN 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 
1100 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N10W CROSSES THE EQUATOR NEAR 
20W THEN ALONG 1S BETWEEN 23W-42W AND INTO NE BRAZIL NEAR 2S45W. 
A CLUSTER OF SCATTERED MODERATE CONVECTION IS FROM 2S-1N BETWEEN 
18W-23W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 100 NM S OF THE AXIS BETWEEN 27W-38W. SIMILAR CONVECTION 
IS FROM THE EQUATOR TO 2N BETWEEN 35W-39W. A CLUSTER OF MODERATE 
TO STRONG CONVECTION IS FROM 1S W OF 40W AND INLAND OVER BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
A 1027 MB SFC HIGH OVER THE FLORIDA BIG BEND REGION EXTENDS A 
RIDGE SOUTHWESTWARD TO THE BAY OF CAMPECHE. A COLD FRONT OVER 
THE SE CONUS IS EXPECTED TO ENTER THE NW GULF IN THE NEXT FEW 
HOURS. SOUTHERLY RETURN FLOW WILL SHIFT W TO NW 15-20 KT 
FOLLOWING THE FRONTAL PASSAGE. DOPPLER RADAR MOSAIC DEPICTS 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS MOVING OFF THE TEXAS 
AND LOUISIANA COASTLINE IN ADVANCE OF THE FRONT. WITH THE 
EXCEPTION OF ISOLATED SHOWERS IN THE STRAIGHTS OF FLORIDA...THE 
REMAINDER OF THE GULF IS MOSTLY CLEAR UNDER MODERATE TO STRONG 
SUBSIDENCE AND DRY AIR ALOFT. 
 
CARIBBEAN SEA...
A SFC TROUGH CONTINUES TO SLOWLY PROGRESS WESTWARD ACROSS THE 
CARIBBEAN. AT 0600 UTC...THE TROUGH CROSSES THE DOMINICAN 
REPUBLIC ALONG 70W AND EXTENDS SOUTHWARD TO NEAR 13N71W. BROAD 
CIRCULATION AND SCATTERED SHOWERS ARE EVIDENT ON SATELLITE 
IMAGERY N OF 14N BETWEEN 68W-74W. THIS TROUGH IS EXPECTED TO  
BECOME DIFFUSE NEAR 76W ON MON. E TO NE WINDS 10-15 KT COVER THE 
ENTIRE BASIN. ALOFT...AN UPPER LEVEL TROUGH IS ACROSS THE NW 
CARIBBEAN WHILE AN UPPER LEVEL RIDGE IS ACROSS THE CENTRAL AND 
ERN CARIBBEAN WITH STRONG SUBSIDENCE AND DRY AIR OBSERVED E OF 
68W.

ATLANTIC OCEAN...
SFC HIGH PRESSURE OVER FLORIDA IS MAINTAINING FAIR 
CONDITIONS ACROSS THE W ATLC...HOWEVER...A COLD FRONT IS 
EXPECTED TO MOVE OFF THE SE US COAST TONIGHT AS THE HIGH WEAKENS 
AND SHIFTS TO THE SOUTHEAST. GALE FORCE WINDS ARE EXPECTED 
WITHIN 240 NM E OF THE FRONT.  FARTHER EAST...A STATIONARY 
FRONT  ENTERS THE DISCUSSION AREA NEAR 31N56W AND EXTENDS TO 
27N62W WHERE IT WEAKENS AND CONTINUES AS A SFC TROUGH TO NEAR 
23N68W. THIS FRONT CONTINUES TO GENERATE SCATTERED SHOWERS N OF 
25N WITHIN 60 NM OF ITS BOUNDARY. THE REMAINDER OF THE ATLC IS 
DOMINATED BY A BROAD SFC RIDGE ANCHORED ON A 1034 MB HIGH NEAR 
31N30W. ALOFT...A DIFFLUENT PATTERN IN THE TROPICS IS ENHANCING 
CONVECTION ALONG THE ITCZ.

$$
WADDINGTON