000 AGXX40 KNHC 160433 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1235 AM EDT THU JUL 16 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 27N87W. 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 WILL 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 15/2250 UTC...HIGHEST NEAR THE COAST OF COLOMBIA...WITH WIND WAVE HEIGHTS OF 8 TO 15 FT. HIGHER WINDS TO 35 KT ARE LIKELY OCCURRING NEAR THE COAST OF COLOMBIA...WHERE LOCAL TOPOGRAPHICAL VARIATIONS ARE LOCALLY ENHANCING THESE WINDS. ALSO...NE WINDS OF 20 KT WILL OCCASIONALLY OCCUR IN THE WINDWARD PASSAGE DURING THE NEXT SEVERAL DAYS. A WESTWARD-MOVING TROPICAL WAVE...CURRENTLY ALONG 74W/75W...WILL QUICKLY MOVE ACROSS THE CENTRAL AND W CARIBBEAN TODAY AND TONIGHT AT 25-30 KT. THE EASTERLY LOW LEVEL JET UPSTREAM OF THE WAVE AXIS IS RATHER STRONG...WITH SPEEDS OF 45-50 KT WITHIN THE 700-600 MB LAYER...AS INDICATED BY THE 16/0000 UTC UPPER AIR OBSERVATIONS OVER THE LESSER ANTILLES. CORRESPONDINGLY...THE LOW LEVEL FLOW REMAINS RATHER INTENSE ACROSS THE CARIBBEAN...AND THIS WILL CONTINUE FOR THE NEXT FEW DAYS...ESPECIALLY GIVEN THE STEEP HEIGHT GRADIENT S OF A LOW/MID-LEVEL HIGH. THE EASTERLY LOW LEVEL JET FOLLOWING THE WAVE WILL CONTINUE SUPPORTING A LARGE AREA OF 20-30 KT EASTERLY SFC WINDS ACROSS A LARGE PART OF THE S CARIBBEAN THROUGH LATE THIS WEEK. GIVEN THE ORIENTATION OF THE TOPOGRAPHY NEAR THE COAST OF COLOMBIA...WINDS WILL LIKELY REACH GALE FORCE THROUGH FRI NEAR THE COAST OF COLOMBIA. THUS...THE GALE WARNING REMAINS IN EFFECT FROM 11N-14N BETWEEN 73W-77W... INCLUDING THAT PORTION OF THE SW AND E CARIBBEAN NEAR THE COAST OF COLOMBIA THROUGH FRI. MAXIMUM SEAS WILL BUILD TO 15 FT NEAR THE COAST OF COLOMBIA BY LATE THIS WEEK. THE WAVE IS 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 IS 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. THE RIDGE WILL TRANSLATE NORTHWARD THIS WEEKEND...WITH A LARGER AREA OF NE TO E TRADE WINDS OF 20 KT ACROSS S PORTIONS OF THE SW NORTH ATLC. A TROPICAL WAVE OVER THE CENTRAL CARIBBEAN AND SW NORTH ATLC IS FOLLOWED BY A STRONG LOW TO MIDDLE LEVEL WIND SURGE. SIGNIFICANT HAZE IN SAHARAN AIR BEHIND THE WAVE WILL DOMINATE THE TROPICAL ATLC DURING THE NEXT COUPLE DAYS. ANOTHER TROPICAL WAVE...CURRENTLY ALONG 43W/44W S OF 16N... WILL LIKELY ENTER THE TROPICAL N ATLC BY SAT. 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 BACKS UP THIS SOLUTION. IN FACT...RECENT RUNS OF THE GFS HAVE BACKED OFF IN DEEPENING THE TROPICAL WAVE TO A LOW. WINDS OF 20 KT...HOWEVER...WILL LIKELY ACCOMPANY THE WAVE. WARNINGS ATLC... .NONE. CARIBBEAN... .GALE WARNING IN EFFECT FOR PORTIONS OF AMZ084 AND AMZ086 THROUGH FRI. GULF OF MEXICO... .NONE. FORECASTER COHEN/CANGIALOSI. TROPICAL PREDICTION CENTER.