000 AGXX40 KNHC 130655 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 255 AM EDT MON JUL 13 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... EAST TO NORTHEASTERLY UPPER LEVEL FLOW AT THE SE 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 ACROSS THE N GULF ALONG 28N WITH A SURFACE HIGH NEAR 28N87W. WINDS ARE LIGHT AND VARIABLE IN THE VICINITY OF THE SURFACE RIDGE. ANTICYCLONIC FLOW AROUND THE RIDGE IS ASSOCIATED WITH A BROAD SWATH OF E WINDS OF 10 KT ACROSS THE SOUTHERN HALF OF THE GULF...WITH NE WINDS OF 10 TO 15 KT IN THE BAY OF CAMPECHE. THESE WINDS ARE GENERATING WIND WAVE HEIGHTS OF 2 TO 3 FT ACROSS THE S GULF. THE SURFACE RIDGE WILL GRADUALLY SINK SOUTHWARD ACROSS THE GULF NEXT WEEK...WITH A WEAKENING PRES GRADIENT AND WINDS DIMINISHING SOMEWHAT ACROSS THE S GULF. HOWEVER...NE WINDS TO 20 KT WILL BE A COMMON OCCURRENCE DURING THE EVENINGS NEAR THE W COAST OF THE YUCATAN PENINSULA...ENHANCED BY NEARBY TERRAIN VARIATIONS. A WEAK NEAR-SURFACE WAVE COULD RIDE EASTWARD ACROSS THE N PERIPHERY OF THE SURFACE RIDGE...LOCALLY INCREASING WINDS TO NEAR 15 KT AND ACCENTUATING A WIND SHIFT ACROSS THE NORTH CENTRAL AND NORTHEAST GULF ON TUE NEAR THE WAVE. BOTH THE GFS AND ECMWF DEPICT THIS SCENARIO...THOUGH THE GFS APPEARS TO OVER-AGGRESSIVELY AMPLIFY THIS FEATURE GIVEN THE LACK OF DEEP-LAYER SUPPORT. CARIBBEAN... FRESH TO STRONG TRADE WINDS WILL AFFECT THE CARIBBEAN DURING THE NEXT SEVERAL DAYS BETWEEN THE SURFACE RIDGE OVER THE GULF OF MEXICO AND CENTRAL NORTH ATLC...AND BROAD LOW PRESSURE OVER NORTHERN SOUTH AMERICA. THROUGH TUE...THE PRIMARY FOCUS OF THESE STRONGER WINDS WILL BE FROM 11N TO 18N W OF 67W. THE STRONGEST WINDS WILL BE FOUND NEAR THE COAST OF COLOMBIA...WHERE WINDS WILL PERIODICALLY REACH 30 KT INTO EARLY THIS WEEK. ADDITIONALLY...SEAS OF 8 TO 11 FT WILL ALSO BE COMMON FROM 11N-18N W OF 70W THROUGH EARLY THIS WEEK. ALSO...NE WINDS TO 20 KT WILL OCCASIONALLY OCCUR IN THE WINDWARD PASSAGE DURING THE SEVERAL DAYS. THE TROPICAL WAVE OVER THE GULF OF HONDURAS AND CENTRAL AMERICA WILL MOVE W OF THE CARIBBEAN DURING THE NEXT DAY. BY EARLY TUE...ANOTHER WESTWARD-MOVING TROPICAL WAVE... CURRENTLY ALONG 49W...WILL ENTER THE E CARIBBEAN. THE EASTERLY LOW LEVEL JET UPSTREAM OF THE WAVE AXIS IS RATHER STRONG...AND IS FORECAST TO INTENSIFY AS THE LOW LEVEL HEIGHT GRADIENT STEEPENS S OF A WEST-SOUTHWESTWARD-DRIFTING HIGH. IN FACT... WINDS AT 700 MB ARE FORECAST TO INCREASE TO 50 KT BEHIND THE WAVE AS IT TRACKS ACROSS THE CARIBBEAN. THE FAST MEAN LOW LEVEL FLOW WILL LIKELY ACCELERATE THE WAVE TO A FORWARD SPEED NEAR 25 KT AFTER IT ENTERS THE CARIBBEAN. THE EASTERLY LOW LEVEL JET FOLLOWING THE WAVE WILL CAUSE THE AREA OF 20-25 KT 10-METER WINDS TO EXPAND ACROSS A LARGE PART OF THE E CARIBBEAN BY WED. GIVEN THE ORIENTATION OF THE TOPOGRAPHY NEAR THE COAST OF COLOMBIA...WINDS WILL LIKELY REACH GALE FORCE ON THU AND FRI NEAR THE COAST OF COLOMBIA. THUS...AN OUTLOOK FOR GALES IS BEING INCLUDED IN THAT PORTION OF THE SW AND E CARIBBEAN NEAR THE COAST OF COLOMBIA. MAXIMUM SEAS WILL BUILD TO 14-15 FT NEAR THE COAST OF COLOMBIA BY LATE THIS WEEK. THE WAVE WILL ALSO BE ACCOMPANIED BY...AND FOLLOWED BY...A STRONG SURGE OF SAHARAN AIR...WHICH WILL LIMIT THE AREAL COVERAGE OF DEEP CONVECTION NEAR THE WAVE...BUT WILL ALSO INCREASE THE THREAT FOR STRONGER DOWNDRAFTS AND GUSTY OUTFLOW WINDS WITH ANY CONVECTION THAT DEVELOPS. ATLC... THE SURFACE PATTERN ACROSS THE AREA WILL BE CHARACTERIZED BY A SURFACE RIDGE ALONG 28N/29N ACROSS THE CENTRAL AND SW NORTH ATLC. THIS 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...WITH SW WINDS OF 15 TO 20 KT ACROSS THE FAR NW PORTIONS OF THE SW NORTH ATLC. WEAK PERTURBATIONS ROTATING AROUND THE RIDGE WILL LOCALLY ENHANCE THESE WINDS TO AROUND 20 KT...WITH SEAS IN THE 6 TO 8 FT RANGE. A TROPICAL WAVE CURRENTLY ALONG 49W IS MOVING W 15-20 KT. A STRONG LOW TO MIDDLE LEVEL WIND SURGE FOLLOWS THE WAVE...AND WILL MOVE ACROSS THE TROPICAL ATLC OVER THE NEXT FEW DAYS. THE POST-WAVE E WINDS OF 20 TO 25 KT WILL GENERATE BUILDING SEAS ACROSS THE TROPICAL N ATLC N OF 13N/14N THROUGHOUT THE WEEK...FORCING THE WAVE TO TILT FROM NE TO SW WITH TIME. THE FRESH TO STRONG TRADE WINDS...AND SIGNIFICANT HAZE IN SAHARAN AIR...WILL DOMINATE THE TROPICAL ATLC BY THE MIDDLE OF THE UPCOMING WEEK WITH THIS WIND SURGE. THE STRONGER WINDS WILL BUILD SEAS TO 8 TO 9 FT. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER COHEN. TROPICAL PREDICTION CENTER.