000 AGXX40 KNHC 271825 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 225 PM EDT MON JUL 27 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... BROAD RIDGE OF HIGH PRESSURE REMAINS IN PLACE OVER THE GULF...EXTENDING OUT FROM THE 1029 MB SFC HIGH LOCATED NEAR 33N53W...WITH A DEEP UPPER LEVEL TROUGH DIGGING SOUTH THROUGH THE MISSISSIPPI VALLEY TO THE CENTRAL GULF COAST. NOT MUCH CHANGE TO THIS PATTERN THROUGH MID-WEEK...WITH GENERALLY E TO SE WINDS OF 5 TO 10 KT OVER THE E GULF...AND SE TO S WINDS OF 10 TO 15 KT OVER THE W GULF. HOWEVER...HIGHER E TO SE WINDS OF 15 TO 20 KT (OCCASIONALLY SHIFTING TO THE NE JUST OFF THE NW COAST OF THE YUCATAN) WILL BE LIKELY ACROSS PRIMARILY E PORTIONS OF THE BAY OF CAMPECHE DURING THE LATE EVENING/EARLY MORNING HOURS (00 TO 06 UTC EACH DAY) FROM MON THROUGH THU. SEAS WILL BE GENERALLY 2 TO 4 FT OVER THE W GULF THROUGH TUE...BUILDING TO 3 TO 5 FT WED AND THU. FOR THE E GULF...SEAS WILL BE GENERALLY 1 TO 3 FT THROUGH TUE...BUILDING TO 2 TO 4 FT BY WED AND THU. CARIBBEAN... MAIN FORECAST CONCERN WILL BE STRONG WINDS OVER THE CENTRAL AND E CARIBBEAN THROUGH LATE THIS WEEK...DRIVEN BY A NUMBER OF PROCESSES: 1. STRONG SURFACE PRES GRADIENT BETWEEN A SURFACE RIDGE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER N PORTIONS OF SOUTH AMERICA AND TROPICAL WAVES TRAVERSING THE BASIN. 2. STRONG LOW-LEVEL EASTERLY WIND SURGES FOLLOWING TROPICAL WAVES OVER THE BASIN. 3. LOCAL ENHANCEMENTS DUE TO TOPOGRAPHICAL VARIATIONS ALONG THE COAST OF COLOMBIA. A TROPICAL WAVE IS CURRENTLY ALONG 65W/66W S OF 20N...AND IS QUICKLY MOVING WESTWARD NEAR 25 KT. THIS WAVE IS BOTH BEHIND AND IS FOLLOWED BY STRONG 30-40 KT 950-800 MB JET CORES...WITH THE STRONGER CORE AHEAD OF THE WAVE. RECENT QUIKSCAT DATA...AS WELL AS SHIP AND BUOY REPORTS...INDICATE A BROAD SWATH OF E WINDS OF 20-25 KT...STRONGEST NEAR THE COAST OF COLOMBIA. THESE WINDS WILL LIKELY INTENSIFY BY THE MIDDLE OF THIS WEEK WITH THE PASSAGE OF THE AFOREMENTIONED TROPICAL WAVE. GLOBAL MODEL GUIDANCE SUGGESTS A NON-ZERO THREAT FOR GALE FORCE WINDS NEAR THE COAST OF COLOMBIA...PARTICULARLY WEDNESDAY MORNING WHEN THE STRONGEST POST-WAVE JET CORE WILL BE JUXTAPOSED WITH THE COAST OF COLOMBIA. HOWEVER...INSUFFICIENT CONFIDENCE EXISTS IN THE GALE POTENTIAL GIVEN THE LACK OF BOUNDARY LAYER MIXING DUE TO THE ABSENCE OF COLD AIR ADVECTION. NEVERTHELESS...THE AREA OF E 20-25 KT WINDS WILL LIKELY EXPAND ACROSS MUCH THE E CARIBBEAN BY LATE WEEK...WITH E WINDS TO 30 KT NEAR THE COAST OF COLOMBIA. THESE WINDS WILL BUILD WIND WAVE HEIGHTS TO 8 TO 12 FT ACROSS MUCH OF THE SOUTHERN TWO- THIRDS OF THE CARIBBEAN THROUGH THIS WEEK...WITH MAXIMUM SEAS TO 14 FT OVER THE CENTRAL CARIBBEAN BY WED AND THU. BUOY 42058 NEAR 15N75W IS ALREADY REPORTING 8 FT SEAS. ANOTHER TROPICAL WAVE ALONG 41W/42W S OF 15N MOVING W NEAR 20 KT WILL REACH THE E CARIBBEAN BY THE MIDDLE OF THIS WEEK...FURTHER SUPPORTING THE STRONG WIND THREAT. ATLANTIC S OF 31N W OF 55W... PERSISTENT DEEP LAYER TROUGH REMAINS OVER THE E UNITED STATES...WITH MOIST SOUTHWESTERLY FLOW ALOFT OVER W PORTIONS OF THE SW NORTH ATLC. SURFACE PRESSURE FALLS RESULTING FROM DEEP LAYER LIFT IN THIS FLOW IS NOW SUPPORTING A SURFACE TROUGH FROM 28N79W TO 32N78W TO N OF THE DISCUSSION AREA. THE RELATIVELY WEAK PRES GRADIENT ON EITHER SIDE OF THIS FEATURE IS KEEPING SUSTAINED WINDS RATHER WEAK OVER THE SW NORTH ATLC...GENERALLY SE 10 TO 15 KT E OF THE TROUGH AND SW 10 TO 15 KT W OF THE TROUGH. HOWEVER...WIND GUSTS UP TO 35 KT ARE LIKELY IN NUMEROUS SHOWERS AND THUNDERSTORMS NEAR THE SURFACE TROUGH...WHERE CONVECTIVE INSTABILITY AND DEEP LAYER MOISTURE CONVERGENCE ARE MAXIMIZED. FARTHER TO THE E...GENERALLY QUIESCENT WEATHER CONDITIONS PREVAIL WITH A DEEP LAYER RIDGE IN PLACE OVER THE CENTRAL ATLC. THE CORRESPONDING ZONALLY-ELONGATED SURFACE RIDGE ALONG 32N/33N IS ANCHORED BY A 1029 MB SURFACE HIGH CENTERED NEAR 33N53W. GENERALLY LIGHT WINDS...E TO SE WINDS OF 10 TO 15 KT...ARE PRESENT S OF THE RIDGE BASED ON THE 27/1015 UTC QUIKSCAT PASS...WITH BUOY REPORTS OVER THE SW NORTH ATLC INDICATING SIGNIFICANT WAVE HEIGHTS OF 3 TO 5 FT. HOWEVER...TO THE SW OF THE BAHAMAS...STRONGER WINDS...E TO SE WINDS OF 20 TO 25 KT...ARE RESULTING FROM THE STRONGER PRES GRADIENT BETWEEN THE AFOREMENTIONED RIDGE AND A TROPICAL WAVE ALONG 65W/66W S OF 20N. LITTLE CHANGE IN THE OVERALL SYNOPTIC PATTERN IS ANTICIPATED OVER THE AREA FOR THE REMAINDER OF THIS WEEK. HOWEVER...WINDS SW OF THE BAHAMAS COULD SLACKEN A BIT BY LATE WEEK AS THE AFOREMENTIONED SURFACE RIDGE SHIFTS NORTHWARD SLIGHTLY. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. $$ FORECASTER COHEN/LEWITSKY