000 AGXX40 KNHC 041856 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 256 PM EDT THU JUL 4 2013 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: GFS/ECMWF/OFFICIAL BLEND THROUGH SUN...THEN GFS BLEND WITH OFFICIAL THROUGH REMAINDER. AVERAGE TO MODERATE CONFIDENCE THROUGH DAY 3...HIGH CONFIDENCE DAY 4-7. RICH TROPICAL MOISTURE CONTINUES TO STREAM NORTHWARD OVER THE EASTERN GULF...BETWEEN A DEEP UPPER LEVEL TROUGH OVER THE CENTRAL PLAINS AND AN UPPER RIDGE OVER THE WESTERN ATLC OFF THE CAROLINAS. THIS CONTINUES TO BRING AREAS OF THUNDERSTORMS OVER THE EASTERN GULF E OF A LINE FROM ABOUT MOBILE TO 25N91W. S OF 25N THE THUNDERSTORMS BECOMES LESS IN COVERAGE. THE UPPER TROUGH CONTINUES TO SUPPORT A WEAK SURFACE TROUGH THAT EXTENDS FROM 27N95W WNW TO A WEAK 1013 MB LOW LOCATED JUST SE OF PENSACOLA. ANOTHER WEAK SURFACE TROUGH IS OVER THE EASTERN BAY OF CAMPECHE ALONG 93W S OF 22N MOVING W AROUND 7 KT. LATEST BUOY AND PLATFORM OBSERVATIONS INDICATE SE-S WINDS OF 15-20 KT IN THE E GULF...EXCEPT N OF ABOUT 27N WHERE A TIGHT GRADIENT THERE BETWEEN THE SURFACE TROUGH AND ATLC SURFACE RIDGING IS RESULTING IN SE-S 20-25 KT WINDS OVER THOSE WATERS. OVER THE REMAINDER OF THE GULF...WINDS ARE LIGHTER N-NE MAINLY IN DIRECTION AT 5-10 KT. WINDS ARE VARIABLE AT TIMES AT 5 KT IN THE SW PART OF THE GULF. THE SHOWER AND THUNDERSTORM ACTIVITY IS AT TIMES PRODUCING GUSTY WINDS. THE OBSERVATIONS SHOW SEAS RANGING FROM 4-7 FT IN THE E GULF TO 2-4 FT ELSEWHERE. THE EXCEPTION FOR MUCH HIGHER SEAS IN THE NE GULF ZONE N OF 27N WHERE SEAS HAVE PEAKED AT 8-10 FT. THE 20-25 KT WINDS IN THE FAR NE GULF ARE EXPECTED TO DIMINISH TONIGHT...HOWEVER THE SEAS WILL WILL REMAIN AT 6-9 FT IN S SWELL THERE. WITH REGARDS TO THE TROUGH OVER THE EASTERN BAY OF CAMPECHE...THE GLOBAL MODELS ARE IN RELATIVELY GOOD AGREEMENT THAT WEAK LOW PRES FORMS ALONG IT THIS EVENING AND MOVES IN A GENERAL WNW MOTION THROUGH SAT. THE 12 UTC GFS MEAN ENSEMBLE ALSO INDICATES THIS FEATURE TO MATERIALIZE BUT TAKES A FURTHER TO THE NW ACROSS THE WESTERN GULF THAN THE 00 UTC ECMWF MEAN ENSEMBLE FROM LAST NIGHT. IN ANY EVENT...THIS FEATURE WILL REMAIN WEAK THROUGH SAT AS IT BEGINS TO ALIGN ITSELF MORE WITH MORE WITH THE TROUGHING IN THE NW GULF THROUGH SAT. FOR DAY 3 WILL DEPICT A TROUGH IN THE GRIDS APPROACHING THE TEXAS COAST PER WPC/NHC MEDIUM RANGE...WITH FORECAST MOVING IT INLAND THE TEXAS COAST SUN NIGHT INTO MON. WINDS ARE EXPECTED TO BE ABOUT NE-E 10-15 KT ALONG AND NEAR THIS TROUGH WITH SEAS AROUND 3-5 FT. STILL CANNOT RULE OUT ENTIRELY THE POSSIBILITY OF WEAK TRANSIENT LOW PRES FORMING ON THE TROUGH BEFORE IT MOVES INLAND AS A STRONG UPPER LEVEL LOW DROPS S ACROSS THE WESTERN GULF SAT INTO SUN BEFORE MOVING W OF THE AREA DURING SUN. OTHERWISE...THE WESTERN EXTENSION OF ATLC HIGH PRES RIDGING WILL BE IN CONTROL OF THE GULF'S WEATHER THROUGH TUE WITH GENTLE TO MODERATE WIND CONDITIONS AND LOW SEAS OUTSIDE CONVECTION. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC... MODEL PREFERENCE: GFS BLEND WITH PREVIOUS OFFICIAL GRIDS. HIGH CONFIDENCE. BUOY OBSERVATIONS AND SCATTEROMETER DATA FROM THIS MORNING SHOW FRESH TO STRONG TRADES CONTINUING OVER THE CENTRAL CARIBBEAN...FRESH E TO SE WINDS OVER THE NW CARIBBEAN...AND FRESH NE TO E WINDS OVER TROPICAL N ATLC W OF 55W. BUOY OBSERVATIONS SHOW SEAS TO 9 FT OVER THE CENTRAL CARIBBEAN WHERE WINDS THE WINDS ARE THE STRONGEST. ONLY MINOR FLUCTUATIONS ARE EXPECTED WITH THESE WINDS THROUGH THE WEEKEND. A WEAK TROPICAL WAVE NEAR 72W IS MOVING WNW NEAR 17 KT. THIS WILL WAVE WILL MOVE ACROSS THE REMAINDER OF THE CENTRAL CARIBBEAN THROUGH FRI NIGHT THEN LOSE ITS IDENTITY OVER THE WESTERN CARIBBEAN SAT AS GUIDANCE TRIES TO INDICATE. EXPECTED SEAS IN THE SW CARIBBEAN TO REACH UP 10 FT...AT TIMES...THROUGH SAT BEFORE SUBSIDING TO 8 FT AND BUILDING BACK UP TO 10 FT LATE MON INTO TUE. ANOTHER TROPICAL WAVE WILL APPROACH THE FAR EASTERN TROPICAL N ATLC FRI EVENING...THEN REACH TO NEAR 58W S OF 17N BY EARLY SAT...AND INTO THE EASTERN CARIBBEAN SUN AND MON...THEN IT APPEARS IT WILL BE DIFFICULT TO TRACK AT THE SURFACE AS IT MOVES FURTHER W ACROSS THE CARIBBEAN. CENTRAL ATLC HIGH PRES BUILDING IN BEHIND IT WILL KEEP TRADES AT AROUND 20 KT ACROSS MUCH OF NORTHERN AND CENTRAL TROPICAL N ATLC. ...SW N ATLANTIC W OF 55W INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS BLEND WITH PREVIOUS OFFICIAL GRIDS. HIGH CONFIDENCE THROUGH DAY 3...AND AVERAGE CONFIDENCE DAY 4-7. AN UPPER LOW NEAR 24N76W CONTINUES TO SUPPORT SCATTERED THUNDERSTORMS ACROSS MUCH OF THE BAHAMAS. THE NORTHERN PORTION OF A TROPICAL WAVE S OF THE LOW HAS NOW SHIFTED TO CENTRAL HISPANIOLA. THE WAVE IS ALSO S OF AN ATLC RIDGE EXTENDING FROM BERMUDA TO NE FLORIDA. LATEST SATELLITE...SHIP...BUOY OBSERVATIONS AND SCATTEROMETER DATA HAVE SHOWN DURING THE DAY...AND ARE CURRENTLY SHOWING MODERATE TO FRESH WINDS OVER THE SOUTHERN PORTION OF THE AREA WITH GENTLE TO MODERATE WINDS PREVAILING OVER THE REMAINDER OF THE FORECAST AREA. SEAS ARE IN THE 4-6 FT RANGE...EXCEPT W OF THE BAHAMAS WHERE SEAS ARE IN THE 3-5 FT RANGE AND S OF 22N WHERE FRESH TRADES ARE SUPPORT 6-8 FT TO BRIEFLY 9 FT. THE RIDGE IS STILL FORECAST TO CHANGE LITTLE THROUGH SAT THEN WEAKEN SUN INTO EARLY NEXT WEEK THE UPPER LOW WEAKENS TO A SHARP TROUGH THEN DISSIPATES AS IT SHIFTS W OF THE AREA. ANOTHER UPPER LOW WILL CUT OFF FROM THE MAIN UPPER TROUGH OVER THE CENTRAL ATLC AND MIGRATE W ALONG 23N/24N FROM 55W THROUGH THE CENTRAL BAHAMAS FRI THOUGH MON...THEN INTERESTINGLY TO ACROSS S FLORIDA LATE MON AND TUE POSSIBLY INCREASING CHANCES FOR CONVECTION ALONG ITS PATH. MODELS SUGGEST THAT A WEAK SURFACE TROUGH MAY EVOLVE FROM THIS LOW...AND MOVE ACROSS THE SOUTHERN PORTION OF THE SW N ATLC ...INCLUDING THE BAHAMAS AND THEN TO S FLORIDA NEXT WEEK ATTENDANT BY 15-20 KT WINDS VEERING FROM NE TO SE ACROSS IT. THIS WILL BE REFLECTED IN THE LATEST PUBLISHED GRIDS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.