000 AGXX40 KNHC 180750 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 345 AM EDT WED JUL 18 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A WEAK 1016 MB HIGH CENTER IS ANALYZED AT 29N87W WITH A RIDGE WSW TO CENTRAL TEXAS. AN ELONGATED UPPER LOW IS NOW IDENTIFIED TO CENTERED OVER THE FAR NE PART OF THE YUCATAN PENINSULA WITH A TROUGH E TO OVER WRN CUBA. SCATTERED SHOWERS AND TSTMS ARE CONFINED TO E OF A LINE FROM ABOUT 29N86W TO 26N87W TO 21N91W. A WEAK SURFACE TROUGH EXTENDS FROM NE FLORIDA SW 27N85W. THE RIDGE IS MAINTAINING LIGHT SEW WINDS TO ITS S ...EXCEPT E-SE WINDS TO THE 88W AS REVEALED BY THE LATEST AND CURRENT BUOY OBSERVATIONS AND REPORTS FROM OIL RIG PLATFORMS. THE ASCAT PASS FROM 0228 UTC LAST NIGHT CAPTURED THE E GULF WINDS. OBSERVED SEAS ARE MOSTLY AT 2 FT...WITH 1-2 FT IN THE FAR ERN PORTION OF THE GULF AND 2-3 FT IN THE SW GULF ZONES. MODELS ARE IN GOOD AGREEMENT THAT THE RIDGE WILL REMAIN IN PLACE THROUGH FRI...THEN LIFT N SAT AND SUN. THE SURFACE TROUGH WILL GRADUALLY BECOME DIFFUSE THROUGH TONIGHT. THE PRES DIFFERENCE BETWEEN THE RIDGE AND BROAD LOW PRES OVER SE MEXICO AND THE FAR SW GULF WILL ALLOW FOR SE 10-15 KT WINDS IN THE SW GULF ZONE TO BRIEFLY INCREASE TO 15-20 KT TONIGHT...AND THROUGH FRI BEFORE DIMINISHING TO 10-15 KT SAT AND SUN. THE NRN PORTION OF TROPICAL WAVE IN THE CARIBBEAN ALONG 83W WILL ENTER THE FAR SE GULF AND YUCATAN CHANNEL TONIGHT...THEN MOVE ACROSS THE YUCATAN PENINSULA THU AND THU NIGHT...AND INTO THE FAR ERN BAY OF CAMPECHE FRI AND REMAINDER BAY OF CAMPECHE AND SW GULF FRI NIGHT THROUGH SAT. THE WAVE WILL PERHAPS SHIFT THE 15-20 KT WINDS IN THE SW BAY OF CAMPECHE FROM NE TO SE ON FRI AS IT TRACKS WWD. IT MAY LIKELY AID IN THE DEVELOPMENT OF CONVECTION OVER THE YUCATAN PENINSULA AND ADJACENT WATERS THU THROUGH FRI. THE MULTIGRID NOAA WAVEWATCH III GUIDANCE WILL BE USED FOR THE THE OFFSHORES FORECAST THROUGH DAY 5 AS IT HAS INITIALIZED CLOSE TO REPORTED SEA STATE VALUES.. SW N ATLC S OF 31N W OF 65W... THE PRELIMINARY 0600 UTC SURFACE ANALYSIS HAS A RIDGE AXIS EXTENDING FROM A 1021 MB HIGH AT 26N66W SW TO S FLORIDA. SATELLITE WATER VAPOR IMAGERY SHOWS THE UPPER LEVEL LOW THAT IN PREVIOUS DAYS MOVED FROM THE NW ATLC TO ACROSS NE FLORIDA IS NOW OVER ERN GEORGIA AT 32N81W. THE NRN PORTION OF A CARIBBEAN TROPICAL WAVE IS WRN CUBA EXTENDING N TO THE WRN STRAITS OF FLORIDA. PARTIAL HIGH RESOLUTION ASCAT DATA FROM 0226 UTC LAST NIGHT ALONG WITH WRN ATLC BUOY OBSERVATIONS REVEALED SW WINDS OF 10-15 KT N OF THE RIDGE W OF 73W...AND S-SW 5-10 KT WINDS E OF 73W. E-SE WINDS OF 10-15 KT ARE NOTED S OF THE RIDGE...WITH E WINDS OF 15-20 KT BETWEEN THE SE BAHAMAS AND PUERTO RICO DUE TO THE SLIGHTER TIGHTER PRES GRADIENT THERE. DEEP ATMOSPHERIC MOISTURE THAT WAS CONFINED OVER THE FAR WRN PART OF THE BASIN HAS THINNED OUT SINCE YESTERDAY WITH THE UPPER LOW NOW HAVING MOVED INLAND THE SE U.S. SO SCATTERED SHOWER AND TSTM ACTIVITY HAS DECREASED OVER THOSE WATERS. THE GLOBAL MODELS FORECAST THE RIDGE TO GRADUALLY LIFT N TO 28N THU THROUGH FRI...TO 29N SAT AND TO 30N SUN. THE 1021 MB HIGH WILL DISSIPATE TONIGHT AS THE RIDGE BECOMES REINFORCED BY STRONGER CENTRAL ATLC RIDGING THAT BUILDS WSW. S OF THE RIDGE...E-SE 10-15 KT WINDS WILL PREVAIL E OF THE BAHAMAS WITH THE 15-20 KT E WINDS BETWEEN THE BAHAMAS AND PUERTO RICO THROUGH THE PERIOD. THE TROPICAL WAVE ACROSS WRN CUBA WILL ENTER THE FAR SE GULF OF MEXICO TONIGHT. A SLIGHTER ENHANCED PRES GRADIENT BEHIND THE WAVE SHOULD LEAD TO STEADY 15 KT E WINDS THROUGH THE STRAITS OF FLORIDA THROUGH SUN. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... A TROPICAL WAVE WITH RATHER GOOD TRACK HISTORY IS IN THE FAR WRN PORTION OF THE CARIBBEAN ALONG 82W N OF 15N MOVING W NEAR 12 KT. BROAD LOW PRES COVERS THE FAR SW CARIBBEAN AND ADJACENT AREAS OF CENTRAL AMERCIA AND S AMERICA. WITH THE WAVE BEING TO THE ESE OF THE GULF OF MEXICO LOW PUTTING IT UNDER THE TYPICALLY DIFFLUENT REGION FOUND TO THE ESE OF AN UPPER LOW...SCATTERED STRONG TSTMS WITH GUSTY WINDS ARE ALREADY BEING NOTED TO THE W OF WAVE FROM 15N TO 18N INCLUDING THE GULF OF HONDURAS. THE 0226 UTC ASCAT PASS FROM LAST NIGHT DEPICTED A SUBTLE NE TO SE WIND SHIFT ACROSS THE WAVE AXIS ALONG WITH INCREASING E WINDS OF 15-20 KT TO ITS SE. ASCAT DATA ALONG SUPPORTED BY WIND OBSERVATIONS FROM BUOY 42058 AT 15N75W NOTE A BROAD SWATH OF NE-E 20-25 KT WINDS COVERING MUCH OF THE CENTRAL CARIBBEAN SEA...AND WRN SECTION OF THE ERN CARIBBEAN. THE ASCAT DATA ALONG WITH OTHER BUOY OBSERVATIONS FROM THE CENTRAL AND ERN CARIBBEAN SEA REVEAL MOSTLY NE-E 15-20 KT WINDS WITH SEAS OF 4-7 FT. SEAS OF 6-8 FT ARE LOCATED WITHIN THE AREA OF 20-25 KT WINDS WITH MUCH HIGHER SEAS OF 8-12 FT TO THE S OF 15N BETWEEN 72W-80W. BUOY 42058 AT 15N75W IS CURRENTLY REPORTING COMBINED SEAS OF 10 FT...AND JUST RECENTLY REPORTED A COMBINED SEA OF 11 FT. ELSEWHERE ACROSS THE CARIBBEAN AND IN THE TROPICAL ZONES LIGHTER NE-E WINDS OF 10-15 KT ARE NOTED IN THE BUOY OBSERVATIONS...AND IN THE TROPICAL N ATLC ASCAT PASS FROM 0044 UTC LAST NIGHT. THE OBSERVED BUOY AND ASCAT DATA MATCH PRETTY WELL WITH BNDRY LAYER MODEL WIND FIELD FROM BOTH THE GFS AND ECMWF MODELS. THE BUOY DATA FROM THE TROPICAL N ATLC ZONE REVEAL SEAS IN THE RANGE OF 5-7 FT THERE. HOWEVER SEAS THERE BUILD TO 8 FT THU...AND CONTINUE THROUGH SUN. IN THE WRN CARIBBEAN SEA W OF ABOUT 83W SEAS ARE LOWER...IN THE 2-4 FT RANGE AS REPORTED BY BUOY 42056 AT 19.7N85W. THE TROPICAL WAVE WILL EXIT THE FAR NW CARIBBEAN AND ENTER THE FAR SE GULF OF MEXICO AND YUCATAN CHANNEL TONIGHT INTO THU. THE MODERATE TO FRESH TRADES THROUGHOUT MUCH OF THE CENTRAL CARIBBEAN WATERS WILL BE FURTHER REINFORCED INTO MOST OF THU AND INTO FRI AS THE ATLC HIGH PRES RIDGE N OF THE AREA STRENGTHENS AND INTERACTS WITH THE RELATIVELY LOWER PRES PRESENT OVER THE SW CARIBBEAN SEA. THE RESULTANT TIGHTER PRES GRADIENT WILL ALLOW FOR THESE WINDS TO EXPAND IN AREAL COVERAGE WITH THE POSSIBILITY OF NE-E WINDS REACHING TO 30 KT ALONG OR NEAR THE COAST OF COLOMBIA LATE THU NIGHT. ANOTHER TROPICAL WAVE IN THE TROPICAL ATLC IS E OF THE FORECAST ZONES ALONG 51W/52W S OF 18N MOVING W AT 15 KT. THIS WAVE WILL ENTER THE FAR ERN PORTION OF THE TROPICAL FORECAST WATERS EARLY TONIGHT...AND MOVE ACROSS THE REMAINDER OF THOSE ZONE THROUGH THU AND THROUGH THE LESSER ANTILLES AND FAR ERN CARIBBEAN THU NIGHT NIGHT INTO FRI. THE WAVE WILL THEN MOVE ACROSS THE REST OF THE ERN CARIBBEAN DURING FRI...THE CENTRAL CARIBBEAN FRI NIGHT AND SAT AND THE WRN PORTION OF THE CARIBBEAN SAT AND SUN. THE PRES DIFFERENCE ARISING BETWEEN THE WAVE AS IT TRACKS WWD INTO THE CARIBBEAN AND THE CENTRAL ATLC RIDGE FORECAST TO BUILDING WWD AND STRENGTHEN...WILL PROLONG THE 15-20 KT E WINDS OVER MUCH OF THE ERN CARIBBEAN AND TROPICAL N ATLC THROUGH THE END OF THE FORECAST PERIOD. ONCE IT REACHES THE CENTRAL CARIBBEAN FRI NIGHT THE SAME SITUATION WITH REGARDS TO THE PROLONGING OF THE STRONGER NE-E TRADES WILL OCCUR ALONG WITH AN EXPANSION OF THE AREAL COVERAGE OF THESE SAME WINDS. THE NOAA MULTIGRID WAVEWATCH III MODEL GUIDANCE BRIEFLY BUILDS SEAS RATHER HIGH...UP TO 15 FT IN THE SW CARIBBEAN TODAY BEFORE LOWERING THEM TO 10-12 FT THU...AND TO 10-11 FRI AND SAT. THE ENSEMBLE GUIDANCE FROM THE NOAA WAVEWATCH III COMBINED WITH THE FNMOC ENSEMBLE HAS EVEN HIGHER SEAS OF 16 FT ON WED AND 15 FT ON THU. THIS IS ABOUT 2-3 FT HIGHER THAN WHAT WAS ADVERTISED IN RECENT DAYS...SO I PLAN ON KEEPING THE CURRENTLY ADVERTISED MAX OF 12 FT THROUGH THE FORECAST PERIOD FOR THE SW CARIBBEAN WATERS WHICH SEEMS MORE SUITABLE GIVEN DURATION AND AREAL COVERAGE OF THE MODERATE TO FRESH TRADES. THIS IS ALSO RATHER CLOSE TO MAX OF 13 FT INDICATED BY THE MEAN ENSEMBLE OF THE NOAA WAVEWATCH III COMBINED WITH THE FNMOC ENSEMBLES. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE