000 AGXX40 KNHC 280730 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 330 AM EDT SUN AUG 28 2011 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... BUOY OBSERVATIONS ALONG WITH A PARTIAL ASCAT PASS FROM 0250 UTC LAST NIGHT SHOW W-NW FLOW PRESENT OVER THE EASTERN AND MIDDLE GULF ZONES N OF 27N...AND OVER THE NW ZONE E OF 94W. WIND SPEEDS ARE IN THE RANGE OF 10-15 KT. ELSEWHERE WINDS ARE SW-W 5-10 KT S OF 27N E OF 85W...NE-E 5-10 KT S OF 27N W OF 85W...AND SW-W 10-15 KT IN THE WESTERN PORTION OF THE NW GULF. OBSERVED SEAS THROUGHOUT ARE IN THE GENERAL RANGE OF 1-3 FT. THE PRELIMINARY SYNOPTIC ANALYSIS REVEALS A WEAK PRES PATTERN OVER THE AREA. A WEAK COLD FRONT EXTENDS FROM NE FLORIDA SW TO 28N86W AND TO 28N90W WHERE IT BECOMES STATIONARY NW TO SW LOUISIANA. THE COLD FRONT WILL MOVE SLOWLY SE THROUGH TONIGHT...THEN BECOME STATIONARY AND DISSIPATE THROUGH MON NIGHT. WINDS WILL TEND TO BECOME VARIABLE 5-10 KT PRETTY MUCH ALL ZONES EXCEPT THE EASTERN ON THROUGH MON NIGHT...THEN BECOME E-SE FLOW AT 10-15 KT OVER MUCH OF THE GULF TUE THROUGH THU...EXCEPT IN THE SW PORTION WHERE WINDS MAY INCREASE SUBSTANTIALLY DUE TO POSSIBLE LOW PRES FORMING IN THE FAR EASTERN BAY OF CAMPECHE AND TRACKING WNW TOWARDS THE MEXICAN COAST THROUGH THU. THE GFS MODEL RUN IS ON THE HIGH SIDE WITH RESPECT TO WINDS INCREASING IN THE SW ZONE DURING THOSE DAYS WITH SPEEDS TO 20 KT. THIS IS WHAT PREVIOUS FORECAST THINKING INCORPORATED INTO THE FORECAST...SO FOR NOW I AM PLANNING ON NOT ADJUSTING THESE WIND SPEEDS FOR TUE THROUGH THU AS WELL AS FOR SEAS RELATED TO THE POSSIBLE LOW. OTHERWISE...ATLC HIGH PRES IS FORECAST TO BUILD WESTWARD OVER THE FAR NORTHERN GULF TUE THROUGH THU. THE GRADIENT BETWEEN THE RIDGE AND THE FORECAST LOW PRES IS WHAT IS EXPECTED TO INCREASE THE WINDS OVER MUCH OF THE SW GULF DURING THE MAJORITY OF THE EARLY TO MIDDLE PART OF THE UP COMING WEEK. LATEST NOAA WAVEWATCH GUIDANCE LOOKS REASONABLE WITH INITIAL SEA STATE VALUES...AND WILL CLOSELY LEAN TOWARDS ITS FORECAST GUIDANCE VALUES FOR THIS NEXT NT4 OFFSHORES FORECAST. SW ATLC S OF 31N W OF 55W... S-SW WINDS OF 20-25 KT LEFT BEHIND FROM THE DEPARTURE OF IRENE ARE EVIDENT OVER THE FAR N CENTRAL AND NE PORTIONS OF THE AREA AS INDICATED BY A FEW SHIP OBSERVATIONS...AND AS SUGGESTED BY THE EDGE OF AN ASCAT PASS FROM 0110 UTC LAST NIGHT. SEAS IN THOSE PORTIONS ARE OBSERVED TO BE THE IN THE RANGE OF 8-11 FT IN PRIMARILY A NW SWELL...WITH THE HIGHEST OF THE SEAS N OF 29N E OF 76W. THESE CONDITIONS WILL SLOWLY SUBSIDE THROUGH TONIGHT AT WHICH TIME WINDS DIMINISH TO 10-15 KT...AND SEAS TO 5-6 IN THE N CENTRAL AND NE PORTIONS. ELSEWHERE WINDS ARE SW 15-20 KT N OF 26N E OF THE BAHAMAS...SE-S 10-15 KT FROM 23N-26N E OF THE BAHAMAS ...E-SE 10-15 KT S OF 23N E OF THE BAHAMAS...AND SW 10-15 KT W OF THE BAHAMAS AND N OF 27N W OF 76W. SEAS ARE IN THE RANGE OF 4-6 FT E OF THE BAHAMAS...6-8 FT N OF 26N E OF THE BAHAMAS ...AND 3-5 FT ELSEWHERE. ALL SEAS ASIDE FROM THOSE MENTIONED ABOVE N OF 29N E OF 76W WILL SUBSIDE TO 2-4 FT...AND TO 1-2 FT W OF BAHAMAS BY WED OF THE UPCOMING WEEK. WINDS WILL TREND DOWNWARD TO THE LIGHT SIDE ACROSS THE AREA BEGINNING TUE AND THROUGH THU. THE PRELIMINARY 0600 UTC ANALYSIS SHOWS A RATHER WEAK PRES PATTERN THROUGHOUT...WHILE A 1010 MB LOW NEAR 30N65W IS MOVING NW AT 8 KT. AN ASCAT PASS FROM 0110 UTC LAST NIGHT REVEALED SE-E WINDS OF 25-30 KT WITHIN ABOUT 70 NM OF THE LOW IN THE SE QUADRANT...WITH VERY LIKELY WINDS TO 35 KT WITHIN THIS QUADRANT AS CONVECTION RAPIDLY FIRES UP OVER THE LOW CENTER. THE LOW IS FORECAST TO MOVE N OF THE AREA THROUGH THIS AFTERNOON. CENTRAL HIGH PRES WILL NOSE SOUTHWESTWARD FROM 27N65W TO THE CENTRAL BAHAMAS TONIGHT...LIFT N TO EXTEND FROM 28N65W TO THE NW BAHAMAS BY TUE...THEN BEGIN TO RETREAT EASTWARD LATE TUE THROUGH THU AS A WEAK COLD FRONT MOVES INTO THE NW PORTION MON NIGHT SLOWLY SHIFTING E AND EXTENDING FROM BERMUDA TO THE CENTRAL BAHAMAS BY THU. WINDS MAY PERIODICALLY INCREASE TO 15-20 KT BETWEEN THE SE BAHAMAS...EASTERN CUBA AND HISPANIOLA TUE AND WED. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... PARTIAL ASCAT DATA ALONG WITH BUOY OBSERVATIONS SHOW MOSTLY LIGHT TO MODERATE E-SE WINDS THROUGHOUT...EXCEPT IN THE CARIBBEAN PORTION S OF 16N BETWEEN 72W AND 77W WHERE WINDS HAVE INCREASED TO 15-20 KT WITH SCATTERED TSTMS PRESENT THERE. WINDS ARE MAINLY NE-E 10 KT IN THE TROPICAL N ATLC ZONE. THE 15-20 KT WINDS IN THE CARIBBEAN S OF 16N BETWEEN 72W AND 77W ARE FORECAST TO EXPAND NORTHWESTWARD INTO THE NW CARIBBEAN SEA TUE THROUGH THU AS CENTRAL ATLC HIGH PRES BUILDS WESTWARD. THE COMBINATION OF THE HIGH AND LOWER PRESSURES OVER NW COLOMBIA WILL INDUCE A TIGHTER PRESSURE GRADIENT ALLOWING FOR THOSE WINDS TO INCREASE TO 15-20 KT. EXPECT SEAS TO BUILD TO 9 FT OVER THE MIDDLE PORTION OF THE CARIBBEAN N OF 11N BETWEEN 67W-80W TUE AND WED. WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE