000
AXNT20 KNHC 042308
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN JAN 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 7N13W 4N24W 3N34W 2N50W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM N OF THE AXIS E OF 23W. 

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT HAS NEARLY ENTERED THE NW WATERS AS LATEST 
SATELLITE IMAGERY AND SFC DATA SUGGEST ITS PRESENCE ALONG 
THE TEXAS COAST.  DOPPLER RADAR SHOWS LITTLE SHOWER ACTIVITY 
ALONG THE BOUNDARY OVER TEXAS BUT SCATTERED ACTIVITY IS NOTED 
FARTHER NE POSSIBLY INFLUENCED BY A WAVE OF LOW PRES ALONG THE 
FRONT. THE FRONT IS EXPECTED TO ONLY DRIFT SE OR POSSIBLY STALL 
OVER THE FAR NW WATERS TONIGHT AND MON AS IT LOSES ITS UPPER 
SUPPORT...BENEATH A LARGE RIDGE OVER THE GULF OF MEXICO. BY MON 
NIGHT AND TUE...THE FRONT WILL BECOME REINFORCED BY AN EWD 
MOVING TROUGH CURRENTLY OVER THE SW CONUS AND WILL THEN MOVE 
RATHER QUICKLY ACROSS THE REGION. UNTIL THEN...LIGHT TO MODERATE 
SE FLOW AND MAINLY FAIR WEATHER WILL LIKELY CONTINUE. 

CARIBBEAN...
A AMPLIFIED MID-UPPER RIDGE IS LOCATED OVER THE W CARIBBEAN... 
EXTENDING NW FROM AN UPPER HIGH NEAR PANAMA...AND TROUGHING IS 
ESTABLISHED OVER THE E CARIBBEAN. THIS PATTERN IS LEADING TO 
WIDESPREAD DRY STABLE AIR AS REVEALED ON WV IMAGERY...ESPECIALLY 
WITHIN THE RIDGE AND IN THE CONFLUENT AREA BETWEEN THE RIDGE AND 
TROUGH. HOWEVER...AS USUAL LOW-LEVEL INSTABILITY IS PRODUCING  
SCATTERED PATCHES OF LOW CLOUDS...BENEATH THE CAP...WHICH ARE 
BEING DRIVEN W BY MODERATE TO FRESH TRADES. THE SHALLOW 
CLOUDINESS HAS SOME STRUCTURE BETWEEN 72W AND 80W...DUE TO THE 
PRESENCE OF A WEAK SFC TROUGH ALONG 76W. THIS TROUGH IS EXPECTED 
TO FIZZLE...OTHERWISE LITTLE SIGNIFICANT CHANGE IS EXPECTED OVER 
THE NEXT COUPLE OF DAYS.  

ATLANTIC...
THE MID-UPPER PATTERN IS NEARLY WLY AND QUITE STRONG ACROSS 
THE ATLC BASIN...THOUGH THERE ARE A COUPLE OF WEAK EMBEDDED 
SHORTWAVE TROUGHS AND RIDGES. THIS FLOW IS SPREADING ABUNDANT 
CLOUDINESS N OF 22N W OF 45W. MOST OF THIS MOISTURE APPEARS TO 
BE IN THE FORM OF MID-HIGH LEVEL CLOUDS...BUT A DEVELOPING WEAK 
LOW-LEVEL TROUGH ACROSS THE SE BAHAMAS IS PROVIDING LIFT 
TRIGGERING HIGHLY SHEARED SCATTERED SHOWERS AND TSTMS FROM 
23N-26N BETWEEN 67W-72W. ANOTHER LOW-LEVEL TROUGH FROM 31N49W TO 
28N53W IS ENHANCING SCATTERED SHOWERS AND TSTMS WITHIN 300 NM E 
OF ITS AXIS. OTHERWISE...SFC HIGH PRES ANCHORED BY A 1028 MB 
CENTER NEAR 34N25W AND A 1022 MB NEAR 29N72W DOMINATE THE SFC 
PATTERN. 

$$
CANGIALOSI