000 AGXX40 KNHC 090658 RRA MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 300 AM EDT SUN AUG 09 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. SW ATLC W OF 55W... DESPITE THE APPROACH OF A WEAKENING COLD FRONT OVER NE WATERS...GENERALLY LIGHT WINDS ARE SEEN OVER MUCH OF THE FORECAST AREA AS EVIDENCED IN BUOY AND SHIP OBSERVATIONS IN ADDITION TO THE 0108 AND 0250 ASCAT PASSES. THE EXCEPTION CONTINUES TO BE THE FAR SOUTHERN WATERS E OF THE BAHAMAS WHERE E-SE WINDS WERE GENERALLY IN THE 15-20 KT RANGE WITH SHIP REPORTS NEAR THE ATLC PASSAGES IN THE 20-25 KT RANGE. LATEST WAVEWATCH GUIDANCE CONTINUES TO WAIT TO BUILD SEAS E OF THE BAHAMAS ABOVE 8 FT UNTIL THU. SURFACE TROUGH OR WEAK LOW MENTIONED IN THE SECTION BELOW MAY POSSIBLY ENTER THE FAR SE PART OF THE SW ATLC ZONE BEGINNING TUE...THEN TO NEAR THE SE BAHAMAS WED. THERE IS CONSIDERABLE UNCERTAINTY ON JUST HOW FAR N THE SYSTEM WILL REACH...AND WHETHER A DEFINITIVE LOW FEATURE DEVELOPS FROM IT OR NOT. TROPICAL ATLC... A TROPICAL WAVE IS CURRENTLY ALONG 82W MOVING W 20 KT. THE WAVE WILL MOVE ACROSS THE REMAINDER OF THE WESTER CARIBBEAN THROUGH SUN AFTERNOON...THEN INLAND THE YUCATAN PENINSULA SUN EVENING. A SECOND WAVE JUST PASSED THROUGH THE LESSER ANTILLES AT 0000 UTC AND WILL MOVE THROUGH THE CARIBBEAN SEA THROUGH WED. FARTHER E...A TROUGH IN THE CENTRAL ATLC EXTENDS FROM 10N53W TO 18N51W MOVING W ABOUT 10 KT TO 15 KT. GLOBAL MODELS STILL HINT THAT A WEAK LOW FORMS ON THIS TROUGH AND TRACKS WNW TO NEAR THE EASTERN FRINGE OF THE TROPICAL N ATLC ON SUN...THEN INTO THE EASTERN CARIBBEAN SEA AND FAR NW PORTION OF THE TROPICAL N ATLC AND FAR SE POTION OF THE SW N ATLC NEXT WEEK. THIS SOLUTION IS STILL QUITE MURKY...ESPECIALLY CONSIDERING THE SYSTEM IS EXPECTED TO MEET UP WITH INCREASINGLY MORE CONFLUENT FLOW ALOFT...WHICH SHOULD INHIBIT CONVECTION...AS IT MOVES THROUGH THE LESSER ANTILLES ON TUE. BY THU...THE STRONG TROPICAL WAVE CURRENTLY NEAR 20W IS EXPECTED TO CROSS 35W INTO THE HIGH SEAS FORECAST AREA. THE MODELS SHOW A CONSIDERABLE AMOUNT OF DISAGREEMENT WITH THE SYSTEM...WITH THE GFS A DEEP OUTLIER BUT IN BETTER AGREEMENT WITH THE MODEL CONSENSUS ON THE TIMING OF THE SYSTEM THAN THE SLOW ECMWF. CARIBBEAN SEA... TRADES WILL CONTINUE IN THE 20 TO 25 KT RANGE OVER MUCH OF THE CENTRAL CARIBBEAN...WITH BRIEF OCCURRENCES OF 25 TO 30 KT WINDS ALONG THE COAST OF COLOMBIA THROUGH SUN AFTERNOON. THE ASCAT PASS FROM 0246 UTC SHOWED WINDS CURRENTLY IN THE 25-30 KT RANGE ALONG THE COAST OF COLOMBIA. AT 0000 UTC...SHIP OBSERVATION VQKZ5 REPORTED THE MAXIMUM SEAS UP TO 14 FT NEAR THE COAST OF COLOMBIA AT 12N76W...WITH SEAS ABOVE 10 FT NOTED AS FAR E AS 14N71W WHERE SHIP 9VKH2 REPORTED 13 FT SEAS. THESE SEAS WILL SUBSIDE SHARPLY BEGINNING MON TO ABOUT 8 OR 9 FT AS THE PRESSURE GRADIENT RELAXES OVER THE CARIBBEAN. THIS STILL APPEARS REASONABLE AT THE PRESENT TIME. GULF OF MEXICO... A WEAK RIDGE REMAINS IN PLACE ACROSS THE NORTHERN GULF. BOTH BUOY OBSERVATIONS AND A QUIKSCAT PASS FROM 0004 UTC SHOWED RELATIVELY LIGHT WINDS WITH THE BUOYS REPORTING SEAS OF 2 FT W OF ABOUT 91W...AND 2 TO 3 FT E OF 91W. THIS IN PRETTY MUCH IN LINE WITH WAVEWATCH MODEL GUIDANCES EXCEPT THE FAR SE WATERS NEAR THE STRAITS OF FLORIDA WHERE SEAS HAVE APPEARED UNDONE BY ABOUT 1 TO 2 FT...WITH THE EXCEPTION OF THE UKMET WAVE GUIDANCE WHICH CAUGHT ON TO THE SLIGHTLY HIGHER SEAS THERE. THERE IS CURRENTLY AN ACCELERATION OF THE EASTERLY FLOW THROUGH THE STRAITS OF FLORIDA ON THE EAST SIDE OF THE TROPICAL WAVE IN THE CARIBBEAN ALONG 82W. THESE WINDS ARE COUNTER TO THE GULF STREAM CURRENT THROUGH THE STRAITS AND MAY INDUCE SOME CONFUSED SEAS WHICH CAN INCREASE SIGNIFICANT WAVE HEIGHTS. THE STRONGER WINDS BEHIND THE TROPICAL WAVE ARE EXPECTED TO DIMINISH BY MORNING. GLOBAL MODEL GUIDANCE AND THE REGIONAL NAM GUIDANCE ARE IN VERY GOOD AGREEMENT THAT THE RIDGE WILL HOLD ACROSS THE NORTHERN GULF THROUGH THE FORECAST PERIOD WITH LITTLE OVERALL CHANGE IN PRESENT OBSERVED CONDITIONS. MODELS...FOR THE MOST PART...STILL HINT THAT A WEAK TROPICAL WAVE MOVE THROUGH THE SOUTHERN WATERS MON THROUGH WED...BUT LITTLE IN THE WAY OF SIGNIFICANT CHANGES TO WINDS AND SEAS WITH IT. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. $$ FORECASTER SCHAUER CLARK/AGUIRRE