000 AGXX40 KNHC 240645 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 245 AM 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 1020 MB HIGH PRESSURE NEAR 28N87W WILL SHIFT E FROM THE GULF INTO THE ATLC TODAY. THE RETURN FLOW HAS ALREADY INCREASED IN THE W GULF AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE INTO THE NW GULF THU. THE 0252 UTC ASCAT PASS SHOWS A REGION OF WIDESPREAD SE WINDS IN THE 20-25 KT RANGE OVER E HALF OF THE SW GULF ZONE AND THERE ARE SEVERAL SHIP OBSERVATION IN THE CENTRAL PORTION OF THE NW GULF ZONE THAT SHOW 20 KT WINDS THIS MORNING. A LOW CUTTING OFF FROM THE NORTHERN STREAM OVER THE FOUR CORNERS STATES IS CURRENTLY PHASING WITH SOUTHERN STREAM ENERGY OVER NW MEXICO AND THE RESULTING TROUGH ALOFT WILL MOVE INTO THE SOUTHERN PLAINS TODAY AND THE MISSISSIPPI VALLEY THU. THE GFS AND ECMWF NEVER FULLY PHASE THESE TWO SYSTEMS. AS A RESULT...THE SURFACE SYSTEM IS WEAKER THAN THE SYSTEM THAT SWEPT THROUGH THE GULF OVER THE WEEKEND. GALES ARE NOT EXPECTED. THE LONGWAVE PATTERN HAS BECOME LESS AMPLIFIED AND MORE PROGRESSIVE. THE GFS IS NOW THE MOST PROGRESSIVE MODEL SOLUTION...WITH THE 0000 UTC ECMWF NOW TRENDING TOWARD ITS FASTER SOLUTION. 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. TROPICAL ATLC AND CARIBBEAN SEA... THE STATIONARY BOUNDARY FROM E CUBA TO HONDURAS EARLIER THIS EVENING IS DETERIORATING. THE 0250 UTC ASCAT PASS AND SEVERAL SHIP OBSERVATIONS W OF THE FRONT N OF 19N STILL SHOW NE WINDS AROUND 20 KT AND SHIP ZCDF4 SHOWED 20-25 KT WINDS AS IT PASSED THROUGH THE WINDWARD PASSAGE FROM 0300 UTC TO 0600 UTC...BUT THERE IS LITTLE CONTRAST ACROSS THE SW END OF THE FRONT INTO HONDURAS AND THE MODELS AGREE ON DIMINISHING THE WINDS N OF THE FRONT TODAY. RETURN FLOW WILL TURN WINDS IN THE NW CARIBBEAN MORE SOUTHEASTERLY BY THU AHEAD OF THE SYSTEM PASSING INTO THE NW GULF OF MEXICO. THE GFS SOLUTION IS PREFERRED WITH THIS FRONT. IT 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...THE ASCAT PASS FROM 0248 UTC SHOWED A SOLID AREA OF 25 TO 30 KT WINDS S OF 15N BETWEEN 70W AND 77W NEAR THE COAST OF COLOMBIA AND SEVERAL SHIP REPORTS SUGGEST 30 KT WINDS AS WELL. STRONG EASTERLY TRADES WILL PERSIST HERE 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 HAVE ALREADY BEGUN TO SHIFT S OF 18N IN THE TROPICAL N ATLC ZONE AS THE COLD FRONT OVER THE SW N ATLC DISPLACES THE SUBTROPICAL RIDGE EASTWARD. THE STRONGEST WINDS 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... THE 0255 UTC ASCAT PASS STILL SHOWS SOME NW WINDS AT 20 KT N OF 30N W OF 77W THIS MORNING...BUT ELSEWHERE WINDS HAVE DIMINISHED BELOW 20 KT W OF THE WEAK COLD FRONT CONTINUES TO MAKE ITS WAY E THROUGH SE WATERS. SHIPS IBNY NEAR 19N67W AND PINX NEAR 20N69W AT 0400 UTC SHOW WINDS REMAIN IN THE 20-25 KT RANGE SE OF THE FRONT. HIGH PRES BUILDS BEHIND THE FRONT WED...WITH WINDS BECOMING VARIABLE THU N OF 25N AS THE NW SWELL PUSHES E OUT OF THE AREA. SOUTHERLY WINDS WILL INCREASE ACROSS THE 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 SLIGHTLY 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 SCHAUER