000 AGXX40 KNHC 151856 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 255 PM EDT FRI MAY 15 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... RETURN FLOW CONTINUES ACROSS THE GULF AROUND A SURFACE RIDGE N OF THE GULF EXTENDING WESTWARD FROM A SURFACE HIGH OVER THE CENTRAL ATLC. E TO SE WINDS OF 10 TO 15 KT PREVAIL ACROSS JUST ABOUT THE ENTIRE GULF AS NOTED BY BOTH BUOY OBSERVATIONS AND A QUIKSCAT PASS FROM NEAR 1200 UTC THIS MORNING. WINDS OVER THE FAR NW GULF FROM 24N TO 26N W OF 95W ARE SE-S 15-20 KT AS REPORTED BY BUOYS NEAR THE TEXAS COAST. RELATED WIND WAVES ARE IN THE 4-6 FT RANGE WITH SEAS OF 3-5 FT IN THE SW PART AND 1 TO 3 FT ACROSS THE REMAINDER OF THE GULF. THIS GENERAL PATTEN OF WINDS AND SEAS IS FORECAST TO CONTINUE THROUGH SAT NIGHT WITH WINDS BECOMING MORE EASTERLY AS THE ATLC RIDGE TO THE NE EXTENDS W ACROSS THE NORTHERN GULF. E-SE WINDS OF 15-20 KT CAN BE EXPECTED OVER THE FAR SE GULF AND STRAITS OF FL THROUGH SAT NIGHT...THEN DIMINISHING TO 10-15 KT ON SUN. NE-E WINDS OF 20-25 KT WILL ALSO OCCUR AROUND THE COAST OF THE YUCATAN PENINSULA DURING THE EVENING HOURS THROUGH SAT NIGHT...DRIVEN BY VARIATIONS IN THE LOCAL TOPOGRAPHY OVER YUCATAN WITH WIND FLOW AROUND THE LAND MASS. GLOBAL MODEL GUIDANCE INDICATES AN OVERALL WEAKNESS IN THE SURFACE PRESSURE GRADIENT ACROSS THE GULF THIS WEEKEND IN RESPONSE TO THE APPROACH OF A SOUTHERN PLAINS COLD FRONT AND POSSIBLE LOW/TROUGH EMERGING FROM NEAR NW CUBA NWD TOWARDS THE VICINITY OF CUBA AND THE NE YUCATAN PENINSULA AS MODELS IMPLY. AS A RESULT...WIND SPEEDS AND SEA HEIGHTS WILL INCREASE THROUGH SUN. WINDS WILL ALSO SHIFT TO N-NE AND INCREASE OVER JUST ABOUT THE ENTIRE GULF. PRESENT MODEL INDICATIONS ARE THAT THIS LOW WILL LIKELY FORM NEAR A SOUTHWESTWARD TRAILING MID-LEVEL TROUGH ASSOCIATED WITH THE AFOREMENTIONED FRONT BEGINNING SOMETIME SUN AFTERNOON INTO MON...AND GENERALLY TRACK IN A N OR NE DIRECTION. IT IS STILL TOO EARLY PINPOINT JUST HOW CLOSE TO THE GULF THIS FEATURE WILL BE NEAR THE GULF. IT STILL APPEARS OF THIS FEATURE WILL BE ON THE WEAK SIDE WITH POSSIBLE INCLINATIONS AS A HYBRID SUBTROPICAL/EXTRATROPICAL LOW OVER THE WESTERN ATLC AS OPPOSED TO THE GULF OF MEXICO. FORECAST CONFIDENCE IS CURRENTLY RATHER LOW WITH THIS UPCOMING SCENARIO...AND WILL CONTINUE TO BE MONITORED. CARIBBEAN SEA... SURFACE HIGH PRESSURE N OF THE CARIBBEAN SEA IS MAINTAINING FRESH NE TO E TRADE WINDS ACROSS THE CARIBBEAN. A PARTIAL QUIKSCAT PASS FROM THIS MORNING SHOWED NE-E WINDS OF 10-15 KT ACROSS THE NW CARIBBEAN...WITH NE TO E WINDS OF 15-20 KT S OF 18NE OF 79W AS NOTED BUOY OBSERVATIONS AND BY A FEW SHIP OBSERVATIONS. WAVEWATCH GUIDANCE FROM 1200 UTC THIS MORNING INDICATES SEAS TO 8 FT IN A SMALL AREA NEAR THE COAST OF COLOMBIA...WITH SEAS OF 4-7 FT ACROSS MUCH OF THE S CARIBBEAN AND 3-5 FT OVER THE REMAINDER OF THE ERN CARIBBEAN AND 2-4 FT IN THE WRN PORTION. THIS COINCIDES PRETTY GOOD WITH CURRENT AND RECENT BUOY AND SHIP OBSERVATIONS. THIS PATTERN IS FORECAST TO PERSIST THROUGH THE WEEKEND. ATLC HIGH PRES THEN SHIFTS EWD LATE SUN AND MON AS WEAK LOW PRES FORMS IN THE VICINITY OF WRN CUBA AND THE YUCATAN CHANNEL. THE LOW INTERACTING WITH THE ATLC HIGH WILL WEAKEN THE PRES GRADIENT ACROSS THE WRN AND MOST OF THE CENTRAL CARIBBEAN...RESULTING IN TRADE WINDS DIMINISHING ACROSS THE ENTIRE CARIBBEAN INTO WED...WITH WINDS GENERALLY IN THE 10-15 KT RANGE WITH MAYBE A FEW INSTANCES OF E 15-20 KT WINDS OVER THE S CENTRAL PORTION. WINDS OVER THE NW PORTION WILL SHIFT CYCLONICALLY AT 10-15 KT AROUND THE LOW AND ASSOCIATED TRAILING TROUGH INTO THE NE YUCATAN PENINSULA. SEA STATE IS EXPECTED TO REACH NO MORE THAN 6 FT BY SUNDAY AREAWIDE AND TO 5 FT BY TUE AND WED. SEAS WILL BE MUCH LOWER...ABOUT 1-2 FT NEAR THE HONDURAN COAST AND 2-3 FT N OF OF THERE OVER THE REMAINDER OF THE NW CARIBBEAN TUE AND WED. SW N ATLANTIC AND TROPICAL N ATLC... QUIKSCAT DATA FROM THIS MORNING SHOWED A WELL-DEFINED E-W SUBTROPICAL RIDGE OVER THE FAR NRN WATERS. E TRADE WINDS AT THE SOUTHERN PERIPHERY OF THIS SURFACE RIDGE ARE GENERALLY IN THE 15-20 KT RANGE ACROSS THE BAHAMAS...GREATER AND LESSER ANTILLES...AND THE TROPICAL N ATLC...WHERE SHIP OBSERVATIONS SHOW SEAS OF 6-7 FT. THE STRONGEST OF THESE WINDS ARE FOUND AROUND A SURFACE TROUGH OVER HISPANIOLA. THE SURFACE HIGH IS FORECAST TO MOVE EWD AS ITS ASSOCIATED UPPER LEVEL RIDGE TRANSLATES EASTWARD IN RESPONSE TO AN UPPER TROUGH CURRENTLY MOVING EASTWARD OVER THE W ATLC. A WEAKENING COLD FRONT IS ALONG 25N65W TO 27N71W. THE FRONT IS FORECAST TO GRADUALLY DISSIPATE THROUGH EARLY SUN AS IT PRESSES S TOWARDS THE NORTHERN PORTION OF THE TROPICAL N ATLC. NE-E WINDS OF 15-20 KT ARE PRESENT N OF THE FRONT WITH SEAS TO 8 FT IN NE SWELL. THESE CONDITIONS DIMINISH INTO EARLY NEXT WEEK. PRES GRADIENT RESULTING FROM THE SURFACE HIGH PRES N OF THE FRONT IS CREATING E WINDS TO 20-25 KT S OF 26N BETWEEN 72W-79W ...PARTICULARLY OVER THE STRAITS OF FL INTO SAT NIGHT...WHERE SEAS WILL BUILD TO AROUND 9 FT. THESE CONDITIONS ARE THEN EXPECTED TO LIFT NWD SUN INTO EARLY NEXT WEEK AS THE WEAK LOW THAT FORMS NEAR WRN CUBA MENTIONED ABOVE BEGINS TO PULL NWD AS A COLD FRONT DROPS INTO THE FAR NW WATERS MON THROUGH WED. A TIGHT GRADIENT BETWEEN THE LOW AND FRONT WILL LEAD TO INCREASING ONSHORE WINDS OF 20-25 KT N OF 26N W OF ABOUT 76W BY WED WITH SEAS BUILDING 8-10 FT. ELSEWHERE WINDS WILL GENERALLY BE NE-E 15-20 KT EXCEPT OVER THE FAR W PORTION S OF THE LOW WHERE WINDS WILL BE LIGHTER ABOUT 10-15 KT SW-S IN DIRECTION...AND SEAS WILL BE IN LOWER RANGES. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER AGUIRRE. TROPICAL PREDICTION CENTER.