000 AXNT20 KNHC 040559 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 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 1S48W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 15W-21W. SCATTERED MODERATE IS WITHIN 90NM N OF THE AXIS BETWEEN 23W-31W. ...DISCUSSION... GULF OF MEXICO... SCATTERED TO NUMEROUS MODERATE CONVECTION IS IN THE NW GULF TONIGHT...N OF 24N AND W OF 87W. THIS IS BEING SUPPORTED BY UPPER DIFFLUENT FLOW BETWEEN THE UPPER LOW MOVING THROUGH NRN MEXICO AND THE UPPER RIDGE EXTENDING NE THROUGH MUCH OF THE GULF FROM ITS ORIGIN S OF EL SALVADOR. FURTHER...THE SFC SUPPORT IS DRIVEN BY A NEW 1013 MB LOW JUST OFF THE COAST OF S TEXAS...THAT HAS A WARM FRONT EXTENDING ENE THROUGH THE MIDDLE GULF AND INTO NORTH CENTRAL FLORIDA. THE SURFACE LOW WILL MOVE NE OF THE AREA AND DRAG A COLD FRONT THROUGH THE NW GULF THROUGH THU NIGHT. 15-20 KT SE TO S FLOW EXPECTED AHEAD OF THE FRONT/LOW INTO THU MORNING/AFTERNOON WHILE SIMILAR W TO NW WINDS DEVELOP BEHIND THE FRONT. WINDS BEHIND THE FRONT DIMINISH THROUGH THU NIGHT 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 UPPER TROUGH EXTENDS FROM HISPANIOLA/PUERTO RICO 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. SAN JUAN RADAR IMAGERY SHOWS THE SHOWERS ARE CURRENTLY FOCUSED IN THE COASTAL WATERS JUST NORTH OF PUERTO RICO. A GALE WARNING REMAINS IN EFFECT NEAR THE COAST OF COLOMBIA. 20-30 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 THU. ATLANTIC OCEAN... DEEP LAYERED TROUGH OVER THE NW ATLC IS SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 31N54W...THEN CONTINUES MAINLY WWD TO 29N61W WHERE IT BECOMES A STATIONARY FRONT THROUGH 29N74W...AND THEN CONTINUES AS A WARM FRONT THROUGH NORTH CENTRAL FLORIDA. SCATTERED SHOWERS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY. THE UPPER RIDGE EXTENDING THROUGH THE GULF AND SW NORTH ATLC WATERS OFF OF FLORIDA IS ADVECTING MOISTURE INTO THE REGION DOWNSTREAM FROM THE CONVECTION OVER THE GULF. A SHORTWAVE TROUGH IS N OF 25N ALONG 72W...WHILE AN UPPER RIDGE COVERS MUCH OF THE REMAINDER OF THE W-CENTRAL ATLC...EXTENDING NE FROM THE LEEWARD ISLANDS THROUGH 32N47W. AN UPPER LOW IS NEAR 22N40W. A TROUGH EXTENDS FROM THIS LOW TO NEAR 12N50W. A SURFACE TROUGH...REFLECTION OF THE UPPER LOW IS ANALYZED FROM 24N44W TO 18N45W. BROAD RIDGE COVERS THE REMAINDER OF THE ATLC. THIS RIDGE IS DRAWING TROPICAL MOISTURE N ON THE E SIDE OF THE UPPER TROUGH GENERATING SCATTERED SHOWERS N OF 10N AND E OF 40W. A 1036 MB SURFACE HIGH LOCATED JUST NORTH OF THE MADEIRA ISLANDS EXTENDS A RIDGE OVER THE E ATLC. THE TAIL END OF A DYING STATIONARY FRONT ENTERS THE AREA NEAR 31N34W THEN CONTINUES SW TO NEAR 24N45W. $$ WILLIS