000 AGXX40 KNHC 150506 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 106 AM EDT WED JUL 15 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 EXTENDING FROM THE SOUTH CENTRAL PLAINS OF THE UNITED STATES INTO THE CENTRAL GULF IS PROVIDING DEEP LAYER SUBSIDENCE ACROSS THE GULF...SUSTAINING A SURFACE RIDGE ACROSS THE N GULF WITH A SURFACE HIGH NEAR 28N89W. 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 10-15 KT ACROSS THE SOUTHERN HALF OF THE GULF. THE RELATIVELY LIGHT WINDS ARE GENERATING WIND WAVE HEIGHTS OF 1 TO 3 FT...WITH HEIGHTS OF 2 TO 4 FT ACROSS THE BAY OF CAMPECHE. THE SURFACE RIDGE WILL REMAIN IN PLACE ACROSS THE GULF FOR MUCH OF THIS WEEK INTO THIS WEEKEND...THOUGH IT WILL SLIDE EASTWARD AS SUBSIDENCE OVER THE GULF WEAKENS IN RESPONSE TO THE SUPPORTING UPPER RIDGE TRANSLATING WESTWARD. 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. FOR SUN...A WEAK COLD BRUSH THE FAR N WATERS N OF THE RIDGE...LOCALLY INCREASING WINDS TO NEAR 15 KT AND ACCENTUATING A WIND SHIFT ACROSS THE NORTH CENTRAL AND NORTHEAST GULF NEAR THE FRONT. BOTH THE GFS AND ECMWF DEPICT THIS SCENARIO. LITTLE UPPER SUPPORT AT THE SOUTHERN END OF THE FRONT WILL PRECLUDE A THREAT FOR STRONGER WINDS. 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. THE PRIMARY FOCUS OF THESE STRONGER WINDS WILL BE ACROSS THE S TWO-THIRDS OF THE CARIBBEAN...WHERE E WINDS OF 20 TO 30 KT ARE ALREADY OCCURRING BASED ON THE QUIKSCAT PASS AROUND 14/2315 UTC...HIGHEST NEAR THE COAST OF COLOMBIA...WITH WIND WAVE HEIGHTS OF 8 TO 15 FT. ALSO...NE WINDS TO 20 KT WILL OCCASIONALLY OCCUR IN THE WINDWARD PASSAGE DURING THE NEXT SEVERAL DAYS. A WESTWARD-MOVING TROPICAL WAVE... CURRENTLY TILTED NW-SE AND EXTENDING FROM 24N63W TO 13N63W TO 7N60W...WILL MOVE ACROSS THE CENTRAL CARIBBEAN TODAY. THE EASTERLY LOW LEVEL JET UPSTREAM OF THE WAVE AXIS IS RATHER STRONG...WITH SPEEDS OF 45-50 KT WITHIN THE 700-650 MB LAYER... AS INDICATED BY THE 15/0000 UTC UPPER AIR OBSERVATIONS OVER THE LESSER ANTILLES. CORRESPONDINGLY...THE LOW LEVEL FLOW IS FORECAST TO INTENSIFY ACROSS THE CARIBBEAN FOR THE NEXT FEW DAYS...ESPECIALLY AS THE LOW LEVEL HEIGHT GRADIENT STEEPENS S OF A WEST-SOUTHWESTWARD-DRIFTING HIGH. THE STRONG MEAN LOW LEVEL FLOW WILL LIKELY ACCELERATE THE WAVE TO A FORWARD SPEED OF 20-25 KT AFTER IT MOVES ACROSS THE CARIBBEAN. ALSO...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 THIS EVENING THROUGH FRI NEAR THE COAST OF COLOMBIA. THUS...A GALE WARNING IS IN EFFECT FROM 11N-14N BETWEEN 73W-77W...INCLUDING THAT PORTION OF THE SW AND E CARIBBEAN NEAR THE COAST OF COLOMBIA WED-FRI. MAXIMUM SEAS WILL BUILD TO 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 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 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 OVER THE W CARIBBEAN IS FOLLOWED BY A STRONG LOW TO MIDDLE LEVEL WIND SURGE. 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. THE FRESH TO STRONG TRADE WINDS...AND SIGNIFICANT HAZE IN SAHARAN AIR...WILL DOMINATE THE TROPICAL ATLC DURING THE NEXT COUPLE DAYS WITH THIS WIND SURGE. THE STRONGER WINDS WILL BUILD SEAS TO 8 TO 9 FT. ANOTHER TROPICAL WAVE...CURRENTLY ALONG 40W S OF 18N...WILL TRACK WESTWARD AT 15-20 KT DURING THE NEXT FEW DAYS. THE WAVE WILL LIKELY ENTER THE TROPICAL N ATLC BY THE END OF THE WEEK. WHILE THE GFS SHOWS THE POTENTIAL FOR TROPICAL CYCLOGENESIS ALONG THIS WAVE...THIS APPEARS TO BE A CONVECTIVE FEEDBACK ISSUE...AS LITTLE GLOBAL MODEL GUIDANCE OR CLIMATOLOGY BACK UP THIS SOLUTION. WINDS OF 20 KT...HOWEVER...WILL LIKELY ACCOMPANY THE WAVE. WARNINGS ATLC... .NONE. CARIBBEAN... .GALE WARNING IN EFFECT FOR PORTIONS OF AMZ084 AND AMZ086 TONIGHT THROUGH FRI. GULF OF MEXICO... .NONE. FORECASTER COHEN. TROPICAL PREDICTION CENTER.