000 AGXX40 KNHC 090730 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 230 AM EDT THU JUN 09 2011 GULF OF MEXICO... WEAK RIDGE EXTENDS E TO W ALONG 29N PER EARLY PRELIMINARY SURFACE ANALYSIS. LATEST BUOY REPORTS THROUGHOUT INDICATE LIGHT WINDS AND LOW SEAS. HIGHER WIND AND SEA CONDITIONS PREVAIL OVER THE FAR SE WATERS WHERE A TIGHT PRES GRADIENT THERE IS MAINTAIN NE-E WINDS OF 15-20 KT THERE DUE TO THE RIDGE TO THE N AND WEAK LOW PRES IN THE NW CARIBBEAN SEA. THESE WINDS WERE CONFIRMED BY AN OBSERVATION FROM SHIP "LAW02" AT 25N84W...AND BY THE WESTERN MOST FRINGE OF AN ASCAT PASS OVER THE MIDDLE STRAITS OF FLORIDA. BUOY REPORTS SHOW SEA HEIGHTS IN THE RANGES OF 1-3 FT...EXCEPT IN THE FAR SE GULF PORTION WHERE SEAS ARE IN THE RANGE OF 4-7 FT WITH THE NE-E 20 KT WINDS. WAVEWATCH GUIDANCE LOOKS REASONABLE FOR THE GULF...EXCEPT MAYBE 1-2 FT BELOW IN VALUES OVER THE FAR SE GULF AND STRAITS OF FLORIDA WHERE STRONGER E FETCH IS OCCURRING. WILL TAKE THIS INTO CONSIDERATION THROUGH FRI...OTHERWISE WILL FOLLOW REST OF VALUES FOR REMAINDER OF GULF FOR THIS FORECAST PERIOD. MODELS SUGGEST THAT THE RIDGE WILL CHANGE LITTLE THROUGH MON AS WEAK LOW PRES IN THE NW CARIBBEAN MOVES SLOWLY NW. THE LOW WILL WEAKEN INTO A TROUGH AS IT MOVES TO NEAR WESTERN CUBA AND THE FAR SE WATERS SAT...AND TO THE SOUTHERN MIDDLE GULF SUN. ALTHOUGH THIS SYSTEM WILL BE WEAK...THE PRES GRADIENT BETWEEN IT AND THE RIDGE WILL BE TIGHT ENOUGH TO ALLOW FOR THE NE-E 20 KT WINDS TO CONTINUE OVER THE FAR SE WATERS THROUGH AT LEAST EARLY FRI EVENING AT WHICH TIME THESE WINDS WEAKEN TO 10-15 KT AND SHIFT TO E-SE. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... THE BROAD AREA OF LOW PRES OVER THE NORTHWESTERN CARIBBEAN SEA DURING THE PAST SEVERAL DAYS HAS BECOME RATHER ILL-DEFINED SINCE THE LAST 24-48 HOURS UNDER UPPER LEVEL SW SHEAR INITIATED BY AN UPPER LEVEL CYCLONIC CIRCULATION LOCATED NEAR 26N88W. AS OF 0600 UTC THIS MORNING THE CENTER OF THE WEAK LOW WAS IDENTIFIED TO BE NEAR 19N31W...OR ABOUT 90 NM SW OF GRAND CAYMAN. A TROUGH EXTENDS FROM NORTHEASTWARD TO ACROSS CENTRAL CUBA. SATELLITE IMAGERY SHOWS AMPLE DEEP MOISTURE TO THE E OF THE LOW NOW CONFINED TO N OF 17N ALLOWING FOR CLUSTERS OF TSTMS TO AFFECT THE WATERS AROUND EASTERN CUBA AND HISPANIOLA. GUSTY WINDS CAN BE EXPECTED WITH THE TSTMS...BUT SHOULD MORE CONFINE TO THE OUTER REACHES OF THE OFFSHORE WATERS AND MOSTLY IN THE COASTAL WATERS OF EASTERN CUBA...HISPANIOLA AND PUERTO RICO DURING THE NEXT 36 HOURS. A PARTIAL ASCAT PASS FROM LATE LAST NIGHT REVEALED SE 15 KT WINDS BETWEEN JAMAICA AND THE LOW...AND NE WINDS OF 15-20 KT IN THE NORTHERN SEMICIRCLE OF THE LOW. SEAS THERE ARE IN THE RANGE OF 3-6 FT. AS THE LOW SLOWLY MOVES NW THROUGH SAT WHILE WEAKENING INTO A TROUGH...EXPECT WINDS OVER JUST ABOUT THE ENTIRE WESTERN CARIBBEAN W OF ABOUT 80W TO BECOME LIGHT IN A SLY DIRECTION. TRADES BEGIN TO INCREASE OVER THE CENTRAL AND EASTERN CARIBBEAN STARTING THU NIGHT AS CENTRAL ATLC RIDGING BUILDS SW TOWARDS THE NORTHERN TROPICAL N ATLC. THESE WINDS WILL REACH 20 KT THU NIGHT THROUGH FRI NIGHT...AND POSSIBLY 20-25 KT SAT AND OVER THE SOUTHERN SECTION OF THE EASTERN CARIBBEAN SEA WITH SEAS MAXING OUT TO 8 OR 9 FT. SW N ATLC... NE TO E WINDS OF 15-20 KT ARE CONFINED TO S OF 27N W OF 76W...AND FROM 22N TO 26N E OF 76W DUE TO A TIGHT PRES GRADIENT BETWEEN HIGH PRES OVER THE NORTHERN AND CENTRAL WATERS...AND THE LOW PRES AND TROUGH IN THE NW CARIBBEAN SEA. MAXIMUM SEAS OBSERVED ARE ABOUT 6-7 FT W OF THE BAHAMAS...AND FROM 22N TO 26N E OF 76W. GLOBAL MODELS FORECAST THE AREA OF HIGH PRES TO SLIDE SE THROUGH SAT AS IT WEAKENS. IN THE MEANTIME WEAK LOW PRES JUST E OF THE FAR SE WATERS MOVES NE. GLOBAL MODELS AND EVEN THE REGIONAL NAM HAVE COME INTO PRETTY GOOD AGREEMENT THAT LOW PRES FORMS BETWEEN THE BAHAMAS AND CENTRAL CUBA THIS AFTERNOON OR EVENING AND TRACKS TO THE N OVER OR JUST E OF THE CENTRAL BAHAMAS THROUGH FRI NIGHT... BEFORE LIFTING N OF AREA LATE SAT NIGHT OR EARLY SUN MORNING. THE GFS IS THE EXCEPTION BY TAKING IT NE ACROSS THE SE BAHAMAS...AND KEEPING IT TO THE E OF THE BAHAMAS FOR FRI AND SAT. FOR NOW WILL DESCRIBE AND ANALYZE THIS FEATURE AS A TROUGH ON NEXT ISSUED FORECAST AND GRAPHICAL CHARTS. ALL MODELS DO AGREE THAT THE MAIN EMPHASIS WITH THIS PROBABLE FEATURE WILL BE THE INCREASING GRADIENT OVER THE WESTERN ATLC WATERS AS THE LOW OR TROUGH TRACKS TO THE N FOR DAYS 4 AND 5. SO WILL HIGHLIGHT THIS FOR THIS FORECAST PACKAGE. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE