000 AGXX40 KNHC 100638 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 240 AM EDT FRI JUL 10 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... NORTHERLY UPPER FLOW AT THE EASTERN PERIPHERY OF A BROAD UPPER LEVEL RIDGE OVER THE SOUTH CENTRAL PLAINS OF THE UNITED STATES IS PROVIDING DEEP LAYER SUBSIDENCE ACROSS THE GULF...HELPING TO SUSTAIN A SURFACE RIDGE ALONG 26N/27N ACROSS THE MIDDLE AND E GULF. WINDS ARE LIGHT AND VARIABLE IN THE VICINITY OF THE SURFACE RIDGE...WHICH IS ASSOCIATED WITH A SURFACE HIGH NEAR 25N86W. ANTICYCLONIC FLOW AROUND THE RIDGE AND HIGH IS ASSOCIATED WITH A BROAD SWATH OF E WINDS OF 15 TO 20 KT S OF THE RIDGE...SUPPORTING WIND WAVE HEIGHTS OF 3 TO 5 FT. THE STRONGEST WINDS ARE FOUND OVER THE SW GULF. LITTLE CHANGE IN THESE CONDITIONS WILL OCCUR DURING THE NEXT SEVERAL DAYS. HOWEVER...THE SURFACE RIDGE WILL GRADUALLY TRANSLATE NORTHWARD INTO THIS WEEKEND...WITH A WEAKENING PRES GRADIENT AND WINDS DIMINISHING SOMEWHAT ACROSS THE S GULF...AND WINDS BECOMING BECOMING NE ACROSS THE SW GULF EARLY NEXT WEEK. A STATIONARY FRONT DRAPED ACROSS THE SE CONUS WILL LIKELY WEAKEN DURING THE NEXT COUPLE DAYS AS ITS ASSOCIATED UPPER SUPPORT LIFTS NE OF THE AREA...WITH LITTLE IMPACT TO THE GULF. CARIBBEAN... FRESH TO STRONG TRADE WINDS WILL AFFECT THE CARIBBEAN DURING THE NEXT SEVERAL DAYS BETWEEN THE SURFACE RIDGE OVER THE CENTRAL NORTH ATLC AND A BROAD TROUGH OVER NORTHERN SOUTH AMERICA. THE PRIMARY FOCUS OF THESE STRONGER WINDS WILL BE FROM 11N TO 18N W OF 66W. THE STRONGEST WINDS WILL BE FOUND NEAR THE COAST OF COLOMBIA...WHERE WINDS WILL PERIODICALLY APPROACH 30 KT INTO EARLY NEXT WEEK. SEAS OF 8 TO 13 FT WILL BE COMMON FROM 11N-18N W OF 66W BY SUN. NE WINDS TO 20 KT WILL OCCASIONALLY OCCUR IN THE WINDWARD PASSAGE DURING THE NEXT WEEK. THE QUIKSCAT PASS FROM AROUND 09/2345 UTC CONFIRMED THE PRESENCE OF THESE STRONGER WINDS IN THE WINDWARD PASSAGE. ALSO...THE TROPICAL WAVE EXTENDING FROM 18N56W TO 7N58W WILL MOVE WESTWARD AROUND 20 KT AND ENTER THE E CARIBBEAN DURING THE NEXT DAY...FOLLOWED BY INCREASED SHOWER AND THUNDERSTORM ACTIVITY AFFECTING THE WINDWARD ISLANDS. THIS TROPICAL WAVE WILL ACCELERATE WESTWARD AS IT INTERACTS WITH THE FRESH TO STRONG TRADE WINDS ACROSS THE CARIBBEAN. ATLC... THE MAIN FORECAST CONCERN IS THE AMPLIFIED DEEP LAYER TROUGH OFF THE EASTERN UNITED STATES COAST. UPPER LEVEL CYCLONIC FLOW ASSOCIATED WITH THIS TROUGH EXTENDS AS FAR S AS THE FLORIDA PENINSULA...THOUGH THE TROUGH WILL DE-AMPLIFY OVER THE NEXT FEW DAYS AND DRIFT EASTWARD AS STRONGER UPPER LEVEL WINDS HAVE ALREADY ROUNDED THE BASE OF THE TROUGH. IN THE MEANTIME...AN ELONGATED SURFACE FRONT IS JUST N OF THE AREA...BEING SUPPORTED BY STRONG UPPER LEVEL DIFFLUENCE E OF THE UPPER TROUGH AXIS. AS THE ASSOCIATED UPPER ENERGY LIFTS N OF THE AREA DURING THE NEXT COUPLE DAYS...THE FRONT WILL LIKELY BECOME INCREASINGLY DIFFUSE WHILE DRIFTING SOUTHWARD INTO THE N WATERS...FOLLOWED BY NE WINDS OF 10 TO 15 KT. HOWEVER...SUFFICIENT DEEP LAYER ASCENT COULD SPIN UP A WEAK FRONTAL WAVE ALONG THE BOUNDARY EARLY SATURDAY...WITH A SMALL THREAT FOR STRONGER WINDS OF 20 KT NEAR THE WAVE. PREVIOUS ITERATIONS OF THE OPERATIONAL GFS WERE MUCH MORE AGGRESSIVE WITH A STRONGER WIND FIELD AROUND THE WAVE...WHICH WERE NOT BACKED UP BY THE GFS ENSEMBLE MEMBERS...OR OTHER GLOBAL MODEL GUIDANCE. THE LATEST GUIDANCE SUGGESTS THAT A WEAK LOW COULD DEVELOP ALONG THE BOUNDARY...BUT LIKELY N OF THE AREA...WITH LITTLE IMPACT TO THE DISCUSSION AREA. OTHERWISE...A SURFACE RIDGE OVER THE CENTRAL NORTH ATLC WILL MAINTAIN NE TO E TRADE WINDS OF 15 TO 20 KT ACROSS THE TROPICAL N ATLC AND FAR SOUTHERN PORTIONS OF THE SW NORTH ATLC FOR THE NEXT FEW DAYS. EARLY NEXT WEEK...AN UPPER LEVEL RIDGE BUILDING OVER THE CENTRAL ATLC WILL INTENSIFY THE SURFACE RIDGE...WITH TRADES INCREASING SOMEWHAT IN COVERAGE OVER THE N TROPICAL ATLC MON INTO TUE. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER COHEN. TROPICAL PREDICTION CENTER.