000 AGXX40 KNHC 290653 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 AM EST TUE DEC 29 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... A TROUGH OVER THE FAR SW GULF WILL SHIFT SLOWLY W TODAY AND WILL LIE N TO S ALONG THE MEXICAN AND TEXAS E COASTS BY TONIGHT. WEAK LOW PRES IS EXPECTED TO DEVELOP ALONG THE TROUGH OVER NE TEXAS NEAR GALVESTON BAY BY LATE TONIGHT. THE LOW WILL THEN MOVE E RIGHT ALONG OR JUST INLAND OF THE CENTRAL U.S. GULF COAST STATES...WHILE DRAGGING A COLD FRONT TO THE E ACROSS THE GULF BY WED...REACHING FROM NEAR 30N87W TO 22N96W BY EARLY THU. A SURGE OF COLD AIR WITH 20-25 KT NORTHERLY WINDS MOVES IN BEHIND THE COLD FRONT THU NIGHT THROUGH FRI...AS STRONG HIGH PRES OVER THE CENTRAL U.S. BUILDS DOWN OVER THE GULF...WITH THE AREA OF LOW PRES MOVING E ACROSS FLORIDA AND INTO THE ATLC. NE-E WINDS WEAKEN FRI NIGHT INTO SAT AS THE AIRMASS MODIFIES WITH HIGH PRES WEAKENING AND THE FLOW EVENTUALLY TURNING MORE TO THE E-SE BY LATE SAT. MEANWHILE...ANOTHER TROUGH IS EXPECTED TO DEVELOP IN THE FAR SW GULF ALONG THE MEXICAN COAST FRI NIGHT TROUGH SAT. CARIBBEAN AND TROPICAL N ATLC W OF 55W... HIGH PRES HAS EXPANDED FROM THE GULF OF MEXICO INTO THE W CARIBBEAN WATERS WITH A TIGHT PRES GRADIENT AND NE-E TRADES IN THE 15-20 KT RANGE W OF 70W...WHICH WILL CONTINUE THROUGH WED. THE PRES GRADIENT TIGHTENS FURTHER WED NIGHT INTO THU WITH TRADES ACROSS THE BASIN INCREASING TO 20-25 KT. STRONGER WINDS IN THE 20-30 KT RANGE WILL PERSIST NEAR THE COAST OF COLOMBIA THROUGH THE PERIOD...DUE TO A WEAK YET PERSISTENT AREA OF LOW PRES LOCATED INLAND OVER COLOMBIA. THE PRES GRADIENT THEN WEAKENS SLIGHTLY THU NIGHT THROUGH SAT ALLOWING FOR THE TRADES TO DIMINISH TO LIGHT TO MODERATE. MEANWHILE...A COLD FRONT WILL DROP S INTO THE NORTHERN TROPICAL N ATLC WED NIGHT...STALLING ALONG 20N THU THROUGH FRI...THEN DISSIPATING FRI NIGHT INTO SAT. LONG PERIOD N SWELL UP TO 16 FEET WILL CONTINUE TO PROPAGATE ACROSS THE ATLC WATERS E OF THE ANTILLES...AND WILL ALSO SEEP THROUGH THE EXPOSED ATLC PASSAGES TODAY AND TONIGHT...THEN WILL GRADUALLY DECAY WED THROUGH FRI. SW N ATLC S OF 31N W OF 55W... A COLD FRONT EXTENDS FROM NEAR 31N64W TO 21N72W...WITH A SECOND COLD FRONT JUST TO THE W FROM NEAR 31N68W TO THE CENTRAL BAHAMAS. THE TWO FRONTS WILL MERGE LATER THIS MORNING...WITH A SURGE OF COLD AIR SPREADING EASTWARD BEHIND THE MERGED FRONT. SOUTHERLY WINDS IN THE 20 TO 30 KT WILL CONTINUE OUT AHEAD OF THE FRONT...AND LATEST MODEL GUIDANCE INCREASES WINDS TO MINIMAL GALE FORCE N OF 28N E OF 64W AHEAD OF THE FRONT DURING THE NEXT FEW HOURS...AND WILL ISSUE A GALE WARNING WITH THE MORNING FCST PACKAGE. THE FRONT WILL REACH FROM 31N55W TO 20N64W BY THIS EVENING...THEN WILL BECOME STATIONARY AND EXTEND FROM 26N55W TO 20N60W TO 20N70W BY WED MORNING. WINDS DECREASE BEHIND THE FRONT ON WED AS BROAD HIGH PRES BUILDS IN...THEN SOUTHERLY WINDS WILL INCREASE W OF 70W WED NIGHT AS RETURN FLOW AHEAD OF THE NEXT COLD FRONT STRENGTHENS ON THU. A SURGE OF COLD AIR ARRIVES BEHIND THE FRONT AS IT MOVES E OF FLORIDA THU NIGHT THROUGH SAT ...AND GALE CONDITIONS APPEAR LIKELY N OF 29N BOTH AHEAD OF AND BEHIND THE COLD FRONT FRI THROUGH SAT. THE FRONT AND WINDS WILL WEAKEN S OF 31N BY LATE SAT...AS THE NORTHERN PORTION PUSHES E OF 55W. WARNINGS... ATLC... .GALE WARNING N OF 28N E OF COLD FRONT THROUGH TUE EVENING. .GALE CONDITIONS EXPECTED N OF 29N W AND E OF COLD FRONT FRI THROUGH SAT. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER LEWITSKY