000
AXNT20 KNHC 091129
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED JAN 09 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
SECTIONS OF SOUTH AMERICA...AND THE 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 AXIS IS CENTERED ALONG 1N3W 2N12W 4N20W 3N40W S OF THE 
EQUATOR NEAR 50W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION ARE FROM 2N TO S OF THE EQUATOR E OF 6W ACROSS THE 
PRIME MERIDIAN AND FROM 6N TO THE EQUATOR BETWEEN 10W-45W. 

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH IS MOVING OVER THE GREAT LAKES REGION TO 
THE N GULF OF MEXICO WITH THE ASSOCIATED COLD FRONT ENTERING THE 
GULF OVER SE LOUISIANA NEAR NEW ORLEANS TO S OF THE TEXAS BORDER 
IN NE MEXICO. THE HEAVIEST SHOWER/THUNDERSTORM ACTIVITY IS OVER 
THE E US WITH ISOLATED SHOWERS FROM THE FRONT W TO THE NW GULF 
COAST. THIS FRONT IS MOVING RAPIDLY EASTWARD OVER THE US AND 
DOWN THE MEXICAN COAST E OF THE SIERRA MADRE MOUNTAINS WHILE 
BECOMING NEAR STATIONARY OVER THE GULF WATERS. BROAD UPPER RIDGE 
EXTENDS FROM THE CARIBBEAN COVERING THE S AND FAR E GULF INTO 
THE W ATLC. THE BROAD SURFACE RIDGE IS RETREATING EASTWARD IN 
THE RESPONSE TO THE COLD FRONT AND EXTENDS FROM THE W ATLC OVER 
SE GEORGIA AND THE FLORIDA PENINSULA. WINDS ACROSS THE GULF HAVE 
MODERATED WITH NORTHERLY FLOW W OF THE FRONT AND WEAKER SOUTH 
AND EASTERLY FLOW ELSEWHERE. FLOW AROUND THE SURFACE RIDGE 
COUPLED WITH THE UPPER LEVEL DIFFLUENCE IS GENERATING AN SMALL 
AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 NM OF 
LINE FROM 26N88W TO 29N84W. 

CARIBBEAN SEA...
BROAD UPPER RIDGE CONTINUES TO DOMINATE THE CARIBBEAN ANCHORED 
OVER SOUTH AMERICA PRODUCING NEAR ZONAL WESTERLY FLOW ACROSS THE 
AREA. THE TIGHT PRESSURE GRADIENT ACROSS THE CARIBBEAN HAS 
RELAXED TO PRODUCE ONLY MODERATE NE TO E TRADE WINDS ACROSS THE 
AREA. THE AREA REMAINS RATHER DRY THIS MORNING WITH SOME WIDELY 
ISOLATED SHOWERS MAINLY FROM 13N-17N BETWEEN 69W-82W. 

ATLANTIC OCEAN...
BROAD UPPER HIGH OVER THE CARIBBEAN EXTENDS INTO THE W ATLC W OF 
75W WITH A BROAD UPPER TROUGH IN THE W/CENTRAL ATLC EXTENDING 
FROM AN UPPER LOW NEAR 25N60W S TO 19N59W. THIS UPPER TROUGH 
COUPLED WITH UPPER LEVEL DIFFLUENCE IS PRODUCING SCATTERED 
SHOWERS/ISOLATED THUNDERSTORMS FROM 22N-29N BETWEEN 45W-61W. A 
SECOND WEAKER UPPER TROUGH IS OVER THE E/CENTRAL ATLC EXTENDING 
FROM 32N43W TO 26N41W AND IS GENERATING AN AREA OF SCATTERED 
SHOWERS AND WIDELY ISOLATED THUNDERSTORMS FROM 27N-31N BETWEEN 
35W-45W. A WEAK SURFACE TROUGH EXTENDS FROM 26N52W TO 19N50W. 
HIGH PRESSURE DOMINATES THE ATLC ANCHORED BY A 1029 AND A 1030 
MB HIGHS N OF THE REGION WITH A WEAKNESS IN THE AREA OF THE 
SURFACE TROUGH. 

$$
WALLACE