000
AXNT20 KNHC 041124
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU JAN 04 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
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 
1115 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 1N AT THE PRIME MERIDIAN TO 3N15W 
4N30W 2N40W CROSSING THE EQUATOR AT 46W TO NE BRAZIL NEAR 2S48W. 
SCATTERED MODERATE CONVECTION IS WITHIN 90NM N AND 60NM S OF THE 
AXIS BETWEEN 21W-32W. 

...DISCUSSION...
GULF OF MEXICO...
SCATTERED TO NUMEROUS MODERATE CONVECTION PERSISTS IN THE NW 
GULF THIS MORNING...N OF 25N AND W OF 90W. THIS IS BEING 
SUPPORTED BY UPPER DIFFLUENCE BETWEEN THE UPPER LOW MOVING 
THROUGH NRN MEXICO AND THE UPPER RIDGE EXTENDING NE THROUGH MUCH 
OF THE GULF FROM ITS ORIGIN JUST S OF EL SALVADOR. FURTHER...THE 
SFC SUPPORT IS DRIVEN BY THE 1012 MB LOW JUST OFF THE COAST OF 
CENTRAL TEXAS...THAT HAS A WARM FRONT EXTENDING E THROUGH THE 
MIDDLE GULF AND INTO NE FLORIDA. THE SURFACE LOW WILL MOVE NE OF 
THE AREA AND DRAG ITS ASSOCIATED COLD FRONT THROUGH THE NW GULF 
THROUGH TONIGHT. 15-20 KT SE TO S FLOW EXPECTED AHEAD OF THE 
FRONT/LOW TODAY WHILE SIMILAR W TO NW WINDS EXPECTED THE FRONT. 
WINDS BEHIND THE FRONT DIMINISH TONIGHT AS WEAK HIGH PRESSURE 
BUILDS OFF THE TX COAST. 

CARIBBEAN SEA...
AN UPPER HIGH JUST S OF EL SALVADOR EXTENDS A RIDGE OVER THE 
YUCATAN PENINSULA AND NW CARIBBEAN. AN ELONGATED UPPER TROUGH 
EXTENDS WSW FROM THE LEEWARD ISLANDS TO PANAMA. VERY DRY 
AIR...RESULTING IN STRONG SUBSIDENCE DOMINATES THE BASIN. ONLY 
PATCHES OF LOW LEVEL MOISTURE ARE BEING CARRIED BY THE TRADE 
WINDS ACROSS THE REGION. THIS IS PRODUCING ISOLATED SHOWERS OVER 
MANY OF THE CARIBBEAN ISLANDS AND THEIR ADJACENT WATERS TONIGHT. 
A GALE WARNING REMAINS IN EFFECT NEAR THE COAST OF COLOMBIA. 
15-25 KT TRADEWINDS ARE OVER THE REMAINDER OF THE CARIBBEAN SEA. 
HIGH PRES OVER ATLC WILL CONTINUE TO PRODUCE FRESH TO STRONG E 
TRADE WINDS THROUGH SUN WITH GALE CONDITIONS JUST OFF OF THE 
COLOMBIAN COAST THROUGH FRI MORNING. 

ATLANTIC OCEAN...
UPPER RIDGE EXTENDING NE THROUGH THE SW NORTH ATLC WATERS OFF OF 
FLORIDA IS ADVECTING MOISTURE INTO THE REGION DOWNSTREAM FROM 
THE CONVECTION OVER THE GULF. A COLD FRONT ASSOCIATED WITH A 
DEEP LAYER TROUGH OVER THE FAR NW ATLC ENTERS THE AREA AT 32N51W 
AND CONTINUES WWD TO 28N63W. A DISSIPATING STATIONARY FRONT THEN 
EXTENDS W TO 30N78W. COASTAL FRONT IS TAKING ITS PLACE OFF THE 
SE US COAST. A SHORTWAVE UPPER TROUGH IS N OF 22N ALONG 
67W...WHILE AN UPPER RIDGE COVERS MUCH OF THE REMAINDER OF THE 
W-CENTRAL ATLC...EXTENDING NE FROM THE LEEWARD ISLANDS TOWARDS 
THE AZORES. AN UPPER LOW IS NEAR 22N40W. A TROUGH EXTENDS FROM 
THIS LOW TO NEAR 12N47W. A SURFACE TROUGH...REFLECTION OF THE 
UPPER LOW IS ANALYZED FROM 24N44W TO 18N45W. BROAD RIDGE COVERS 
THE REMAINDER OF THE E ATLC. THIS RIDGE IS DRAWING TROPICAL 
MOISTURE N AND E ON THE E SIDE OF THE UPPER TROUGH...N OF 10N 
AND E OF 40W. A 1034 MB SURFACE HIGH LOCATED JUST NORTH OF THE 
MADEIRA ISLANDS EXTENDS A RIDGE OVER THE E ATLC.

$$
WILLIS