000 AGXX40 KNHC 241908 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 308 PM EST WED MAR 24 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... THE 102S MB HIGH OVER THE BIG BEND REGION WILL SHIFT E-NE AND INTO THE ATLC THIS EVENING. RETURN FLOW WAS ALREADY WELL ESTABLISHED BY THIS MORNING...WITH SE FLOW OF 20-25 KT FROM NEAR 25N95W INTO THE BAY OF CAMPECHE. BUOYS 42002 AND 42055 HAVE BEEN FLUCTUATING AT AND JUST BELOW 8 FT ALL DAY. AS THE HIGH SHIFTS FURTHER E TONIGHT AND THU RETURN FLOW WILL SPREAD TO ENTIRE GULF BY WED NIGHT AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE INTO THE NW GULF THU. THE GFS AND ECMWF HAVE CONTINUED TO COME CLOSER INTO PHASE WITH THE MID LEVEL ENERGY SUPPORTING THIS NEXT FRONT...BUT HAVE NEVER FULLY PHASE THESE TWO SYSTEMS...AND THUS FRONTAL ENTRANCE INTO THE NW GULF STILL REMAINS WITH 3-6 HR DIFFERENCE BETWEEN THE TWO MODELS. THE FRONT IS WEAKER THAN THE SYSTEM THAT SWEPT THROUGH THE GULF OVER THE WEEKEND AND GALES ARE NOT EXPECTED. THE LONGWAVE PATTERN HAS BECOME LESS AMPLIFIED AND MORE PROGRESSIVE. BOTH MODELS TAKE THE COLD FRONT OFF THE TEXAS COAST THU MORNING AND QUICKLY MOVE IT FROM THE FL BIG BEND TO THE NW YUCATAN PENINSULA LATE THU NIGHT BEFORE MOVING THE FRONT E OF AREA AND DISSIPATING THE SW PORTION FRI NIGHT. HIGH PRES CHASES THE FRONT OUT OF THE GULF AND QUICKLY SHIFTS E SAT TO MAKE WAY FOR THE NEXT COLD FRONT ENTERING THE NW GULF SUN. THIS FRONT IS EXPECTED TO BE MORE AMPLIFIED THAN THE FRONT MOVING OFFSHORE THU...BUT THE SYSTEM WILL BE PROGRESSIVE ENOUGH UNDER THIS PATTERN TO PREVENT GALE FORCE WINDS FROM DEVELOPING. THE GFS IS FASTER THAN THE ECMWF AND PREFERRED FOR THIS FORECAST CYCLE FOR BOTH FRONTS. TROPICAL ATLC AND CARIBBEAN SEA... THE STATIONARY BOUNDARY FROM E CUBA TO HONDURAS YDA EVENING HAS BECOME DIFFUSE AND WAS DRIFTING NW ACROSS THE SE BAHAMAS THIS AFTERNOON. LATE MORNING SCATTEROMETER PASSES CLEARLY SHOW A WEAK BOUNDARY ACROSS THE SE BAHAMAS ACROSS E CUBA...WITH LITTLE SIGNAL FARTHER W IN THE CARIBBEAN. RETURN FLOW WILL TURN WINDS IN THE NW CARIBBEAN MORE SOUTHEASTERLY BY THU AHEAD OF THE SYSTEM PASSING INTO THE NW GULF OF MEXICO...AND ONLY CLIPS THE NORTHERN CARIBBEAN LATE FRI NIGHT/SAT MORNING. WINDS WILL REMAIN SOUTHEASTERLY INTO THE NW CARIBBEAN THROUGH THE WEEKEND IN RESPONSE TO THE NEXT COLD FRONT MOVING THROUGH THE WESTERN AND CENTRAL GULF OF MEXICO SUN. ELSEWHERE IN THE CARIBBEAN...MORNING SCAT PASSES SHOWED A BROAD ZONE OF 20-25 KT WINDS BETWEEN 65W AND 79W WITH THE TYPICAL 25-30 KT OFF OF COLOMBIA. TRADES WILL GRADUALLY DIMINISH...EXCEPT ALONG THE SRN CORRIDOR...THROUGH FRI. ON SAT...THE STRONG PRES GRADIENT BETWEEN THE SUBTROPICAL HIGH AND LOW PRES OVER COLOMBIA IS WEAKENED AS THE HIGH SHIFTS E AHEAD OF THE FRONT PASSING FROM THE GULF OF MEXICO INTO THE ATLC...BUT THE RIDGE TO THE N IS RESTORED ON SUN. MEANWHILE... FRESH TO STRONG TRADE WINDS AFFECTING THE TROPICAL ATLC E OF THE ISLANDS YDA HAVE DIMINISHED AND SHIFTED THROUGH THE E CARIBBEAN. THE STRONGEST TRADES ACROSS THE TROPICAL ATLC WILL CONTINUE TO SHRINK S THROUGH FRI WITH SEAS SUBSIDING BELOW 8 FT. HIGH PRES BEHIND THE COLD FRONT WILL QUICKLY PASS NE OF THE TROPICAL N ATLC ZONE FRI AND SAT...ALLOWING FRESH TRADES TO REBUILD S OF 18N...BUT LOOK FOR THE NEXT COLD FRONT TO MOVE INTO N WATERS AT THE END OF THE PERIOD...REDUCING THE PRES GRADIENT AND THE TRADES AND BRINGING LIGHT AND VARIABLE WINDS TO THE REGION N OF THE FRONT. SW N ATLC W OF 65W... MORNING SCAT PASSES STILL INDICATE A SECONDARY BENIGN FRONTAL TROUGH BEHIND THE MAIN FRONT IN THE W ATLC...WITH 20 KT WINDS STILL SWEEPING EWD ALONG 30N. OTHERWISE...THE HIGH OVER NW FLORIDA WILL MOVE INTO THE ATLC TONIGHT TO MAINTAIN THE DECREASING WIND AND SEA TREND OF THE PAST 18 HOURS...AND WINDS WILL GRADUALLY VEER AROUND TO NE TO E BY EARLY THU MORNING AND THEN S TO SE W PORTIONS BY EVENING. SOUTHERLY WINDS W OF 75W WILL INCREASE LATE THU AS THE PRES GRADIENT BUILDS BETWEEN THE HIGH TO THE E AND THE SYSTEM TRAVERSING THE GULF OF MEXICO TO THE W. THE FORECAST CALLS FOR THE COLD FRONT TO ENTER FAR NW WATERS FRI AND QUICKLY TREK E THROUGH THE N PORTION OF THE FORECAST AREA THROUGH SAT. SOUTHERLY RETURN FLOW BUILDS IN NW WATERS SUN AHEAD OF THE NEXT FRONT IN THE GULF OF MEXICO. THE MORE PROGRESSIVE GFS IS PREFERRED WITH THIS PROGRESSIVE PATTERN. HOWEVER...THE GFS DEVELOPS A STRONG COAST LOW AT THE VERY END OF THE FORECAST PERIOD AND BUILDS S WINDS TO 30 KT AHEAD OF THE FRONT. CONFIDENCE IS LOW IN THE STRENGTH OF THE SYSTEM...SO HEDGED CONTINUED WITH WEAKER WITH THE WINDS FOR NOW. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING