000 AGXX40 KNHC 200758 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 355 AM EDT TUE AUG 20 2013 UPDATED TO INCLUDE NEW LOW FEATURE ALONG GULF OF MEXICO STATIONARY FRONT 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 WITH HIGH CONFIDENCE. A WEAK SURFACE TROUGH IS JUST E OF THE NE MEXICO AND FAR SOUTHERN TEXAS COASTS. A TROPICAL WAVE EXTENDS FROM NEAR 26N87W SSW TO INLAND THE N CENTRAL YUCATAN PENINSULA MOVING W AT 10-15 KT. ATLC HIGH PRES RIDGING EXTENDS SW ACROSS CENTRAL FLORIDA...AND TO THE EASTERN GULF PORTION. LATEST BUOY AND PLATFORM OBSERVATIONS REVEAL GENTLE TO MODERATE WINDS THROUGHOUT WITH PREVAILING DIRECTION GENERALLY FROM THE E TO SE. E WINDS OF 15-20 KT CONTINUE THROUGH THE STRAITS OF FLORIDA. THE ASCAT PASS FROM 0334 UTC NICELY CAPTURED THE NE TO SE WIND SHIFT ACROSS THE WAVE. THE BUOY OBSERVATIONS ALONG WITH A RECENT ALTIMETER SHOW SEAS IN THE RANGE OF 2-3 FT THROUGHOUT. HIGHER SEAS OF 3-4 FT ARE IN THE FAR SE PART...WITH SEAS TO 6 FT IN THE STRAITS OF FLORIDA. WW3 GUIDANCE LOOKS REASONABLE WITH THESE OBSERVED VALUES...WILL USE GUIDANCE FOR THIS FORECAST. THE SURFACE TROUGH WILL MOVE INLAND IN JUST A FEW HOURS. THE TROPICAL WAVE WILL MOVE WESTWARD ACROSS THE S CENTRAL GULF PORTION THROUGH TONIGHT...THEN WEAKEN AS IT TRACKS NW TO NEAR 94W BY EARLY WED...AND TO 95W BY WED NIGHT. SCATTERED SHOWERS AND ISOLATED TSTMS WILL ACCOMPANY THE WAVE. THE HIGH PRES RIDGE OVER THE EASTERN GULF WILL WEAKEN THU THROUGH SAT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...MODEL PREFERENCE: PREVIOUS FORECAST BLENDED WITH LATEST GFS WITH HIGH CONFIDENCE. THE 0600 UTC PRELIMINARY SURFACE ANALYSIS HAS A TROPICAL WAVE ALONG 71W/72W MOVING W AT 10-15 KT. THE BUOYS INDICATE GENTLE TO MODERATE NE TO E TRADES THROUGHOUT. A PARTIAL ASCAT PASS FROM NEAR 0200 UTC LAST NIGHT SHOWED NE WINDS OF 15-20 KT NEAR THE COAST OF COLOMBIA. THE BUOYS INDICATE SEAS IN THE RANGE OF 4-5 FT...EXCEPT FOR 2-3 FT IN THE SE PART OF THE CARIBBEAN AND 5-6 FT IN THE SW AND FAR N CENTRAL CARIBBEAN AREAS...AND OVER MUCH OF THE CENTRAL TROPICAL N ATLC WATERS. GUIDANCE SUGGESTS THE WAVE WILL MOVE ACROSS THE REMAINDER OF THE CENTRAL CARIBBEAN THROUGH WED...THEN ACROSS THE WESTERN PORTION OF THE CARIBBEAN THU INTO MUCH OF SAT. LIKE THE PREVIOUS WAVE IT SHOULD BE HAVE LITTLE IMPACT OVERALL ON WINDS AND SEAS. THE ONLY EXCEPTION WILL BE IN THE SW CARIBBEAN SECTION WHERE A TIGHT GRADIENT IN THE WAKE OF THE WAVE WILL KICK UP THE TRADES THERE TO 20-25 KT BEGINNING TONIGHT...AND POSSIBLY LASTING INTO THU WITH SEAS BUILDING TO 8 FT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: PREVIOUS FORECAST BLENDED WITH LATEST GFS WITH HIGH CONFIDENCE. A RIDGE EXTENDS FROM NEAR BERMUDA SW TO ACROSS CENTRAL FLORIDA. THE RIDGE WILL BE THE DOMINANT FEATURE ACROSS THIS AREA THROUGH MOST OF THIS FORECAST PERIOD KEEPING AN E-SE WIND FLOW OF MODERATE SPEEDS THROUGHOUT...EXCEPT IN THE FAR NW PORTION WHERE GENTLE SE-S WINDS ARE NOTED. THE BUOYS THROUGHOUT ALONG WITH A FEW SHIP OBSERVATIONS ARE CURRENTLY REPORTING SEAS OF 3-5 FT...EXCEPT FOR LOWER SEAS OF 2-3 FT IN THE NW PORTION AND 4-6 FT E OF THE BAHAMAS...EXCEPT FOR A SMALL POCKET OF HIGHER 6-7 FT SEAS BETWEEN THE SE BAHAMAS AND HISPANIOLA WHERE A TIGHTER PRES GRADIENT EXISTS ALLOWING FOR 20 KT E WINDS. THIS TIGHTER PRES GRADIENT IS FOUND BETWEEN THE NORTHERN PORTION OF THE CARIBBEAN TROPICAL WAVE ALONG 71W/72W...AND THE RIDGE. THE WAVE WILL CONTINUE WESTWARD MOVING THROUGH THE ATLC APPROACH TO WINDWARD PASSAGE TONIGHT AND WED...AND SHOULD REACH THE STRAITS OF FLORIDA LATE THU INTO FRI. IN ITS WAKE...THE SURGE OF E 20 KT WINDS WILL FOLLOW WITH SEAS OF AROUND 7 OR 8 FT. THE RIDGE IS FORECAST TO WEAKEN THU THROUGH SAT...WITH WIND AND SEAS CONDITIONS THROUGHOUT ON THE RELATIVELY LOW SIDE EXCEPT BETWEEN THE SE BAHAMAS AND HISPANIOLA WHERE THE EXISTING TIGHTER PRES GRADIENT SHOULD ALLOW FOR SEAS OF 6-7 FT THROUGH WED NIGHT...LOWERING JUST A BIT TO 5-6 FT THU INTO EARLY FRI AND TO 4-5 FT THEREAFTER. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.