000
AXNT20 KNHC 171106
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI JAN 17 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 
1030 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N20W 2N30W 1N40W AND INTO 
NE BRAZIL NEAR THE EQUATOR AND 49W. THE ITCZ IS QUITE ACTIVE 
THIS MORNING WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
ALONG THE AXIS FROM 1N-5N BETWEEN THE COAST OF AFRICA AND 30W. 
AN ADDITIONAL CLUSTER OF MODERATE CONVECTION IS WITHIN 50 NM OF 
THE AXIS BETWEEN 38W-42W.

...DISCUSSION...

THE GULF OF MEXICO...
A 1036 MB HIGH OVER THE SOUTHEAST CONUS EXTENDS A RIDGE OVER 
FLORIDA AND THE ENTIRE GULF MAINTAINING BELOW AVERAGE 
TEMPERATURES. WINDS IN THE NW GULF HAVE TURNED SOUTHERLY AND 
WEAKENED TO 15 KT IN RESPONSE TO THIS RIDGE BEGINNING TO SHIFT 
EASTWARD. NE WINDS 15-20 KT FLOW ACROSS THE REMAINDER OF THE 
BASIN. A COLD FRONT IS EXPECTED TO FOLLOW THE RIDGE...ENTERING 
THE NW GULF ON SUN. SWLY FLOW ALOFT IS ADVECTING HIGH CLOUDS 
OVER THE SW CARIBBEAN AND FAIR WEATHER STRATOCUMULUS CLOUDS ARE 
NOTED IN THE CENTRAL GULF. ELSEWHERE...MOSTLY CLEAR SKIES 
PERSIST IN THE DRY AIR MASS.

THE CARIBBEAN SEA...
A STATIONARY FRONT LINGERS IN THE NW CARIBBEAN...GENERATING 
SCATTERED SHOWERS IN THE VICINITY. AS OF 0900 UTC...THE FRONT 
ENTERS THE BASIN OVER CENTRAL CUBA AND EXTENDS ACROSS THE CAYMAN 
ISLANDS TO NEAR 16N84W. NE WINDS 20-25 KT COVER THE NW CARIBBEAN 
BEHIND THE FRONT. THIS BOUNDARY IS EXPECTED TO MOVE SLOWLY 
EASTWARD BEFORE BECOMING DIFFUSE ON SUN. A SFC TROUGH LIES OVER 
THE EASTERN CARIBBEAN FROM THE EASTERN TIP OF PUERTO RICO TO 
NEAR 12N66W. BROAD CIRCULATION SURROUNDING THIS TROUGH IS 
EVIDENT ON SATELLITE IMAGERY. SAN JUAN DOPPLER RADAR SHOWS 
SCATTERED SHOWERS MOVING ACROSS THE VIRGIN ISLANDS AND PUERTO 
RICO. ADDITIONAL SHOWERS ARE OVER THE E CARIBBEAN WATERS N OF 
14N BETWEEN 64W-70W. THIS TROUGH IS EXPECTED TO BECOME DIFFUSE 
OVER THE CENTRAL CARIBBEAN NEAR 75W ON MON. STRONG SUBSIDENCE 
AND DRY AIR ALOFT PREVENT CONVECTION IN THE CENTRAL CARIBBEAN. 
MODERATE TO STRONG TRADE WINDS PERSIST ACROSS THE BASIN.

THE ATLANTIC OCEAN...
A DEEP-LAYER TROUGH OVER THE EASTERN SEABOARD SUPPORTS A FRONTAL 
BOUNDARY ACROSS THE W ATLC. THE STATIONARY FRONT ENTERS THE 
DISCUSSION AREA NEAR 30N62W AND EXTENDS ACROSS THE BAHAMAS AND 
OVER CENTRAL CUBA INTO THE CARIBBEAN. MULTI-LAYER CLOUDS AND 
SCATTERED SHOWERS FILL IN THE W ATLC BEHIND THE FRONT. FARTHER 
SOUTH...A SFC TROUGH EXTENDS FROM 22N64W SOUTHWARD ACROSS PUERTO 
RICO AND INTO THE CARIBBEAN. SCATTERED SHOWERS ASSOCIATED WITH 
THE TROUGH ARE SOUTH OF 24N BETWEEN 58W-68W. A STRONG SFC RIDGE 
ANCHORED ON A 1033 MB HIGH NEAR 32N33W COVERS THE REMAINDER OF 
THE ATLC. ALOFT...A DIFFLUENT PATTERN IN THE TROPICS IS 
ENHANCING CONVECTION AROUND THE ITCZ.

$$
WADDINGTON