000 AXNT20 KNHC 151728 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI DEC 15 2006 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ AXIS IS ALONG 6N11W 4N39W EQ49W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 120 NM S OF AXIS BETWEEN 12W AND 15W...AND WITHIN 120 NM N OF AXIS BETWEEN 41W AND 45W. ...DISCUSSION... THE GULF OF MEXICO... WATER VAPOR IMAGERY SHOWS WELL DEFINED SHORT WAVE TROUGH MOVING OFF THE NRN GULF COAST OF MEXICO THIS MORNING. SURFACE OBSERVATIONS SHOW 1017 MB HIGH PRES ANCHORED OVER THE LOWER MISSISSIPPI VALLEY...MAINTAINING LIGHT TO MODERATE ELY FLOW ACROSS THE GULF. SLIGHTLY LOWER SEA LEVEL PRESSURES OVER THE WESTERN GULF ALONG WITH WEAK CYCLONIC TURNING HINT AT DEVELOPMENT OF A WEAK SURFACE TROUGH NEAR THE MEXICAN COAST ASSOCIATED WITH UPPER LEVEL SHORT WAVE. MEANWHILE SURFACE OBSERVATIONS OVER THE EASTERN GULF OF MEXICO AND THE FLORIDA PENINSULA ARE SHOWING A BETTER TEMPERATURE GRADIENT FROM THE FLORIDA BIG BEND AREA TO S FLORIDA. TEMPERATURES REMAIN IN THE LOWER TO MID 60S OVER NORTH FLORIDA...AND EVEN IN THE 50S OVER THE WESTERN PANHANDLE...WHILE GETTING ONLY TO THE LOWER TO MID 70S OVER THE EXTREME SE COAST OF FLORIDA WITH NE FLOW. THIS INDICATES FRONTALGENESIS IS STARTING ALONG THE EXISTING TROUGH LINE FROM SOUTH FLORIDA TO THE NE AHEAD OF SHORT WAVE TROUGH MOVING ACROSS THE GULF WATERS. SURFACE OBSERVATIONS AND QUIKSCAT IMAGERY SHOW NE TO E CONVERGENCE ALONG THE TRAILING TROUGH FROM S FLORIDA TO THE YUCATAN. THE CARIBBEAN SEA... MODERATE TO FRESH ELY FLOW PERSISTS ACROSS THE CARIBBEAN BASIN...EXCEPT FOR LIGHT SE FLOW BETWEEN JAMAICA AND THE YUCATAN. LIGHT SHOWERS AND BROKEN CLOUD DECKS ARE EVIDENT NEAR A WEAK TROUGH IN THE YUCATAN CHANNEL AND AS FAR S AS THE BELIZE COAST. SPEED CONVERGENCE OVER THE SW CARIBBEAN IS PROMOTING SCATTERED SHOWERS FROM THE NRN COAST OF PANAMA TO THE NICARAGUAN COAST. OTHERWISE GENERALLY FAIR CONDITIONS PREVAIL UNDER DRY SUBSIDENT AIR ALOFT. THE ATLANTIC OCEAN... OCCLUDED LOW PRES COMPLEX SITUATED NEAR SW OF THE AZORES NEAR 27N32W WITH COLD FRONT EXTENDING TO AROUND 15N40W. AN EARLY MORNING QUIKSCAT PASS SHOWS NEAR NLY GALE FORCE WINDS WRAPPING AROUND THE LOW PRES APPROXIMATELY 240 NM TO THE W. LARGE NLY SWELL PERSISTS IN THIS AREA AS WELL WITH COMBINED SEA HEIGHTS OF 14 TO 18 FT. A LARGE FIELD OF STRATO CUMULUS CLOUDS EXTEND BEHIND THE FRONT AS FAR W AS 55W. CONVERGENT FLOW IS GENERATING AREAS OF SHOWERS AND MULTILAYER CLOUD DECKS ALONG THE FRONTAL BOUNDARY AND WITHIN 60 NM OF A LINE EXTENDING TO THE LEEWARD ISLANDS. DRY SUBSIDENT AIR AND FAIR CONDITIONS PERSIST OTHERWISE ACROSS THE ATLC N OF THE ITCZ. 1032 MB HIGH PRES IS CENTERED NEAR 38N42W. GRADIENT BETWEEN THIS HIGH AND THE OCCLUDED LOW IS MAINTAINING FRESH NE TO E WINDS N OF 14N AND W OF 40W...WITH MODERATE TO FRESH ELY WIND PREVAILING TO THE S OF THIS AREA. FURTHER W...COLD FRONT IS EMERGING OFF THE SE COAST N OF THE BAHAMAS...FOLLOWED BY 1024 MB HIGH PRES CELL SHIFTING E THROUGH THE CAROLINAS. THE FRONT WILL PROGRESS EWD THROUGH THE WEEKEND INTO THE CENTRAL ATLC AS THE HIGH PRES BUILDS OVER THE WRN ATLC. WINDS AND SEAS WILL VEER MORE NE AND INCREASE SLIGHTLY W OF 60W AS HIGH PRES BUILDS TO N. MEANWHILE THIS WILL WEAKEN THE 1032 MB HIGH OVER THE CENTRAL ATLC...ALLOWING WINDS TO DIMINISH SLIGHTLY TO THE S. THE HIGH PRES OVER THE WRN ATLC WILL CONTINUE TO BUILD E THROUGH EARLY NEXT WEEK AS THE COMES IN PHASE WITH THE OCCLUDED LOW AND LIFTS OUT TO THE NE. $$ CHRISTENSEN