000 AGXX40 KNHC 210743 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 340 AM EDT WED AUG 21 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: PREVIOUS FORECAST BLENDED WITH LATEST GFS AND MWW3 WITH HIGH CONFIDENCE. WILL ADJUST SEAS ABOUT 1 FT HIGHER THAN MWW3 GUIDANCE IN STRAITS OF FLORIDA INTO FRI. THE PRELIMINARY SURFACE ANALYSIS HAS A WEAKENING TROPICAL WAVE S OF 26N ALONG 91W MOVING SLOWLY WESTWARD. HIGH PRES EXTENDS FROM THE ATLC SW ACROSS THE NE AND AND CENTRAL GULF. THE PRES PATTERN ACROSS THE AREA REMAINS RATHER WEAK. LATEST BUOY AND PLATFORM OBSERVATIONS ALONG WITH A FEW SHIP REPORTS DEPICT MAINLY GENTLE TO MODERATE WINDS ACROSS THE AREA. IN ADDITION... ASCAT DATA FROM JUST PAST 0300 UTC LAST NIGHT SHOWED SIMILAR WIND CONDITIONS. LATEST AND RECENT OBSERVATIONS SHOW RATHER LOW SEAS...IN THE 1-3 FT RANGE...WITH THE EXCEPTION OF THE STRAITS OF FLORIDA WHERE HIGHER SEAS OF 3-5 FT EXIST DUE TO THE LONG DURATION OF 15 KT E WINDS. THE TROPICAL WAVE WILL CONTINUE TO WEAKEN AS IT REACHES NEAR 95W TONIGHT...BECOMING RATHER DIFFUSE THEREAFTER AS IT APPROACHES NE MEXICO AND FAR SOUTHERN TEXAS. LITTLE OVERALL CHANGES WILL BE EXPECTED WITH CURRENT WIND AND SEAS CONDITIONS THROUGHOUT THE FORECAST PERIOD AS A WEAK PRES GRADIENT PREVAILS. WINDS AND SEAS MAY BE HIGHER IN AND NEAR SHOWER/TSTM ACTIVITY. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: PREVIOUS FORECAST BLENDED WITH LATEST GFS AND MWW3 WITH HIGH CONFIDENCE. A TROPICAL WAVE IS ANALYZED AT 0600 UTC ACROSS THE CENTRAL CARIBBEAN WATERS FROM HAITI TO INLAND COLOMBIA AT 12N73W MOVING W AT ABOUT 10-15 KT. A WEAK SURFACE TROUGH IS TO THE E OF THE WAVE ALONG A POSITION FROM JUST SE OF HISPANIOLA TO JUST W OF THE ABC ISLANDS. LATEST BUOY OBSERVATIONS REVEAL N-E TRADES IN THE FRESH CATEGORY IN SPEEDS OVER MUCH OF THE CENTRAL AND EASTERN SECTION OF THE CARIBBEAN. SATELLITE-DERIVED WINDS OVER THAT SAME AREA SHOW SIMILAR WIND SPEEDS AS WELL. A PARTIAL ASCAT PASS FROM 0128 UTC LAST NIGHT DEPICTED SIMILAR CONDITIONS WITH HIGHER RAIN-FLAGGED WIND VECTORS OVER THE WESTERN HALF OF THE EASTERN CARIBBEAN DUE TO EARLIER CONVECTION THAT HAD FIRED UP WITHIN 120 NM E OF THE TROUGH LAST NIGHT. RECENT SATELLITE IMAGERY SHOWS THAT THE CONNVECTION HAS JUST ABOUT DISSIPATED. THE BUOY OBSERVATIONS ARE REPORTING GENTLE NE TRADES ACROSS THE TROPICAL N ATLC ZONES WITH A POCKET OF LIGHT TO GENTLE NE WINDS OVER ZONE 037. THE BUOY OBSERVATIONS ARE RECORDING SEAS OF 4-6 FT RANGE IN THE EASTERN AND CENTRAL CARIBBEAN SECTIONS WITH A POCKET OF 6-7 FT SEAS WHERE THE EARLIER DEEP CONVECTION WAS NOTED E OF THE AFOREMENTIONED TROUGH. AN AREA OF 2-3 FT SEAS IS IN THE SE PART OF THE EASTERN CARIBBEAN...AND ALSO W OF ABOUT 79W WHERE A RECENT ALTIMETER PASS VERIFIED THESE VALUES. HIGHER SEAS OF 6-8 FT ARE NOW EVIDENT IN THE SW PORTION...ESPECIALLY NEAR THE COAST OF COLOMBIA WHERE NE-E WINDS HAVE INCREASED TO 20-25 KT. SEAS IN THE TROPICAL ATLC ARE SLIGHTER LOWER THAN 24 HOURS...IN THE 4-5 FT EXCEPT 3-4 FT S OF 13N AS INDICATED BY A RECENT ALTIMETER PASS. GUIDANCE SUGGESTS THAT THE TROPICAL WAVE AXIS WILL REACH FROM THE VICINITY OF CENTRAL CUBA TO JAMAICA TO NEAR 13N76W BY EARLY THIS EVENING...FROM WESTERN CUBA TO 15N80W BY DAYBREAK ON THU ...AND FROM FAR NW CUBA TO JUST E OF NE HONDURAS BY EARLY THU EVENING. BY FRI EVENING...THE WAVE IS EXPECTED TO BE APPROACHING THE NORTHERN YUCATAN PENINSULA AND GULF OF HONDURAS AREA. THE WAVE WILL THEN CROSS THE YUCATAN PENINSULA DURING FRI NIGHT... ...AND INTO SAT. IN THE WAKE OF THE WAVE...THE AREA OF 20-25 KT WINDS IN THE SW CARIBBEAN IS FORECAST TO EXPAND TO ENCOMPASS MUCH OF THE CENTRAL PART OF THE SEA INCLUDING THE EASTERN HALF OF THE WESTERN CARIBBEAN THROUGH SUN AS LOW PRES OVER COLOMBIA REMAINS DEEPER THAN TYPICALLY OBSERVED. WITH THESE WINDS SEAS WILL BE IN THE 6-9 FT RANGE. ELSEWHERE...CONDITIONS ARE EXPECTED TO VARY LITTLE THROUGH THE PERIOD WITH THE EXCEPTION OF THE CENTRAL PORTION OF THE TROPICAL N ATLC WHERE SEAS WILL BUILD AGAIN TO THE 5-6 FT RANGE IN AN E SWELL BEGINNING FRI. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: PREVIOUS FORECAST BLENDED WITH LATEST GFS AND MWW3 WITH HIGH CONFIDENCE. THE NORTHERN EXTENT OF A TROPICAL WAVE IS MOVING THROUGH THE SE BAHAMAS...WHILE A SURFACE RIDGE PREVAILS N OF THE FORECAST AREA ROUGHLY ALONG 32N. LATEST AND RECENT BUOY OBSERVATIONS ALONG WITH SEVERAL SHIP REPORTS REVEAL MODERATE TO FRESH E WINDS S OF 24N BETWEEN 69W AND 78W...INCLUDING THE APPROACH TO THE WINDWARD PASSAGE. THE WESTERN EDGE OF THE 0132 UTC ASCAT PASS FROM LAST NIGHT SUGGESTED SIMILAR CONDITIONS AS ALSO DID RECENT SATELLITE- DERIVED WIND DATA. ELSEWHERE THE BUOY OBSERVATIONS...ASCAT AND SATELLITE-DERIVED WIND DATA INDICATE LIGHTER E-SE WINDS IN THE GENTLE TO MODERATE TYPE INTENSITY. THE WINDS OF GENTLE CATEGORY ARE NOTED N OF 29N. THE BUOYS AND SHIP OBSERVATIONS ARE NOTING SEAS IN THE 4-5 FT S OF 26N...EXCEPT SEAS TO 8 FT BETWEEN THE SE BAHAMAS AND HISPANIOLA WHERE THE E MODERATE TO FRESH ARE OCCURRING. N OF 26N SEAS ARE LOWER...IN THE 3-4 FT RANGE...EXCEPT FOR 2-3 FT W OF THE BAHAMAS...AND N OF THE BAHAMAS W OF 79W. IN THE FAR SW PORTION AND STRAITS OF FLORIDA SEAS ARE IN THE 3-5 FT RANGE UNDER A STEADY E FETCH OF 15 KT TO OCCASIONALLY 20 KT WINDS. THE TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE REMAINDER OF THE FAR SOUTHERN THROUGH EARLY THU BEFORE IT MOVES FARTHER W ACROSS THE STRAITS OF FLORIDA IN THE AFTERNOON AND EVENING. BEHIND IT...A LOCALLY TIGHTER PRES GRADIENT WILL PREVAIL BETWEEN THE BAHAMAS...AND HISPANIOLA WITH E-SE WINDS THERE PULSATING TO 20 KT AND TO AROUND 8 FT THROUGH WED NIGHT...AND TO 6 FT THEREAFTER. ELSEWHERE ACROSS THE BASIN...THE RIDGE ALONG 32N IS FORECAST TO BEGIN TO SHIFT S THU AND WEAKEN IN RESPONSE TO A WEAK COLD FRONT THAT PUSHES SWD TO THE FAR NW PORTION SAT AND SUN. A RATHER LIGHT PRES GRADIENT WILL REMAIN OVER THE NORTHERN AND CENTRAL WATERS ALLOWING FOR ONLY MINOR CHANGES TO WINDS AND SEAS THERE THROUGHOUT THE PERIOD. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.