000
AXNT20 KNHC 041135
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 9N10W 4N26W 4N42W 1N52W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N TO 
JUST S OF THE EQUATOR E OF 20W TO ACROSS THE PRIME MERIDIAN. 

...DISCUSSION...

GULF OF MEXICO...
UPPER RIDGE ANCHORED OVER CENTRAL AMERICA IS GIVING THE GULF 
STRONG WLY FLOW WITH MID/UPPER LEVEL MOISTURE STREAMING ACROSS 
THE N GULF. A JET STREAM WITH WINDS OF 80-110 KT WITHIN 150/200 
NM OF A LINE ACROSS CENTRAL TEXAS AND S LOUISIANA INTO THE GULF 
NEAR 30N90W TO ACROSS THE FLORIDA PENINSULA NEAR TAMPA. A 
SHORTWAVE UPPER TROUGH IS MOVING OVER ALABAMA AND GEORGIA A BAND 
OF HEAVY RAINS AND THUNDERSTORMS ALONG THE N GULF COAST WITHIN 
45 NM OF LINE FROM 28N87W OVER THE FLORIDA PANHANDLE BETWEEN 
PENSACOLA AND PANAMA CITY. A SURFACE RIDGE ANCHORED IN THE W 
ATLC COVERS THE E GULF WITH SLY RETURN FLOW AROUND THE RIDGE 
COVERING THE ENTIRE GULF. A SURFACE FLOW AROUND THE SURFACE 
RIDGE IS GIVING THE NE GULF SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS N OF 27N E OF 90W TO OVER FLORIDA. SE 
SURFACE FLOW IS GENERATING SCATTERED SHOWERS IN THE FLORIDA 
STRAITS BETWEEN CUBA AND 25N BETWEEN 79W-84W INCLUDING THE 
FLORIDA KEYS. STRONG SUBSIDENCE AND DRY STABLE AIR IS GIVING THE 
REMAINDER OF THE GULF CLEAR SKIES THIS MORNING. THE NEXT COLD 
FRONT IS FORECAST TO ENTER THE NW GULF LATE TODAY/TONIGHT.

CARIBBEAN SEA...
BROAD UPPER RIDGE ANCHORED OVER CENTRAL AMERICA COVERS THE NW 
CARIBBEAN WHILE A SECOND UPPER RIDGE ANCHORED OVER THE E PORTION 
OF SOUTH AMERICA IS GIVING THE REMAINDER OF THE CARIBBEAN SW TO 
W UPPER FLOW. STRONG SUBSIDENCE AND DRY STABLE AIR COVERS THE 
AREA W OF 70W. MODERATE/STRONG ELY TRADE WINDS ARE SUPPLYING THE 
E CARIBBEAN WITH LOW LEVEL MOISTURE AND COUPLED WITH A SURFACE 
TROUGH THAT EXTENDS FROM THE MONA PASSAGE TO THE ABC ISLANDS ARE 
GENERATING SCATTERED SHOWERS FROM 13N-19N BETWEEN 67W-72W. THESE 
TRADE WINDS AND LOW LEVEL MOISTURE ARE PRODUCING FAST MOVING 
ISOLATED SHOWERS SE OF A LINE FROM SW HAITI TO COSTA RICA TO 
OVER THE LESSER ANTILLES. THE NW CARIBBEAN REMAINS RATHER CLEAR 
THIS MORNING. 

ATLANTIC...
STRONG WLY FLOW ALOFT REMAINS OVER THE W ATLC WITH A WEAKENING 
JET STREAM OF 80-100 KT WITHIN 150 NM OF LINE FROM ACROSS 
FLORIDA NEAR VERO BEACH TO 23N67W. DEEP LAYERED TROUGH COVERS 
THE AREA N OF 25N FROM 50W-65W WITH THE ACCOMPANYING FRONTAL 
BOUNDARY ALONG THE N PORTION OF THE REGION THROUGH 32N60W 31N67W 
THEN NW TO INLAND OVER SOUTH CAROLINA. A SURFACE RIDGE REMAINS 
IN CONTROL OF THE REMAINDER OF THE ATLC INTO THE E GULF OF 
MEXICO WITH A 1021 MB HIGH NEAR 28N70W. FARTHER TO THE E...A 
REMNANT SURFACE TROUGH EXTENDS INTO THE CENTRAL ATLC NEAR 32N45W 
TO 26N59W GENERATING SCATTERED SHOWERS WITHIN 120/150 NM SE OF 
THE TROUGH AND WITHIN 120 NM N OF THE TROUGH E OF 52W. AN UPPER 
RIDGE COVERS THE AREA S OF 30N FROM 30W-60W AND A SURFACE RIDGE 
REMAINS OVER THE E ATLC ANCHORED BY A 1028 MB HIGH NEAR 35N24W 
BRIDGING THE ABOVE FRONT/TROUGH AND GIVING THE E ATLC FAIR 
WEATHER THIS MORNING. 

$$
WALLACE