000 AGXX40 KNHC 171902 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT TUE AUG 17 2011 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE PRELIMINARY 18 UTC SURFACE ANALYSIS SHOWS A WEAK 1019 MB HIGH CENTERED OVER THE NW GULF NEAR 27N93W MAINTAINING A RATHER WEAK PRES GRADIENT. A WEAKENING STATIONARY FRONT IS ANALYZED OVER THE NORTHERN PORTION OF THE GULF EXTENDING FROM JUST N OF TAMPA FLORIDA NW TO SE LOUISIANA. ISOLATED SHOWERS AND TSTMS ARE S OF THE FRONT TO 26N. RECENT BUOY OBSERVATIONS ARE SHOWING LIGHT N-NE WINDS N OF THE FRONT...AND LIGHT SE 5 KT S OF THE FRONT. ELSEWHERE WINDS ARE VARIABLE 5-10 KT WITH THE EXCEPTION OF THE SW ZONE WHERE WINDS ARE E-SE 10 KT. SEAS CONTINUE ON THE LOW SIDE...IN THE RANGE OF 1-2 FT THROUGHOUT...EXCEPT IN THE SW ZONE WHERE SEAS ARE GENERALLY 2-3 FT. VERY LITTLE OVERALL CHANGES ARE EXPECTED IN THE FORECAST FOR THE GULF THROUGH MON. THE STATIONARY FRONT OVER THE NE GULF WILL LIFT N AS A WARM FRONT THROUGH THU. A WEAK TROUGH IN THE NW CARIBBEAN SEA WILL MOVE THROUGH THE YUCATAN CHANNEL...AND INTO THE FAR SE GULF TONIGHT AND THU. IT WILL HAVE LITTLE EFFECT ON WINDS AND SEA WITH ONLY ISOLATED SHOWERS AND TSTMS POSSIBLY MOVING ACROSS THOSE WATERS. A LOW PRES SYSTEM...POSSIBLY A TROPICAL CYCLONE...WILL MOVE FROM THE WESTERN CARIBBEAN SEA WESTWARD ACROSS THE YUCATAN PENINSULA LATE FRI AND SAT... WITH THE NORTHERN FRINGE EXPECTED TO MOVE ACROSS THE EASTERN BAY OF CAMPECHE ON SUN...AND BECOME DIFFUSE IN THE WESTERN PORTION OF THE BAY OF CAMPECHE LATE SUN INTO MON. STAY TUNED TO THE LATEST INFORMATION ON THE TROPICS FOR THE LATEST INFORMATION ON THIS FEATURE. OTHERWISE...WINDS AND SEAS THROUGHOUT WILL VARY VERY LITTLE THROUGH MON OVER THE REMAINDER OF THE GULF WITH THE EXCEPTION OF POSSIBLE HIGHER WINDS AND SEAS NEAR SHOWERS AND TSTMS. CARIBBEAN SEA... LATEST ASCAT DATA FROM 1400 UTC THIS MORNING ALONG WITH OBSERVATIONS SHOW THAT WINDS REMAIN RATHER LIGHT OVER MUCH OF THE CARIBBEAN. SEAS THROUGHOUT ARE IN THE 3-5 FT RANGE...EXCEPT IN THE SW ZONE NEAR THE COAST OF COLOMBIA WHERE HIGHER SEAS...IN THE RANGE OF 6-7 FT ARE NOTED. STILL THE MAIN WEATHER FEATURE IS THE VIGOROUS TROPICAL WAVE APPROACHING 76W EARLY THIS AFTERNOON. THE ASCAT PASS SHOWED SHOWED NE-E WINDS OF 20 KT N OF 15N BETWEEN THE WAVE AND 70W. HOWEVER...TO THE E AND SE OF THE WAVE WINDS SHIFT SHARPLY TO THE SE AS BUOY 42060 AT 16N64W IS SHOWS SE WINDS OF 10-15 KT WITH SEAS OF 3-4 FT. LATEST SATELLITE IMAGERY SHOWS THE ASSOCIATED CLOUD PATTERN OF THE WAVE NOW HAVING BECOME MORE CONSOLIDATED AND CIRCULAR. SCATTERED SQUALLS AND TSTMS MOVING QUICKLY TO THE W ARE OBSERVED FROM 14N TO 18N BETWEEN 72W AND 78W. THE 12 UTC GLOBAL MODELS FROM THIS MORNING ARE IN GENERAL AGREEMENT ON THE INITIAL STRENGTH OF WINDS WITH THE WAVE. WITH RESPECT TO FUTURE TRACK...THE GFS HAS MORE OF A TREND TO THE SW AS COMPARED TO THE OTHER MODELS. THE MAIN QUESTION WITH THIS FEATURE WILL BE IF AND AT WHAT TIME DOES LOW PRES FORM ALONG THE WAVE AXIS. THE NCEP MODELS FROM 12 UTC THIS MORNING SUGGEST THAT LOW PRES FORMS ALONG THE WAVE WHEN IT ENTERS THE WESTERN CARIBBEAN SEA THU NEAR 79/80W. BASED ON THE FACT THAT THE WAVE IS MOVING AT A FAST PACE FOR THE TIME BEING...I WOULD EXPECT LOW PRES TO FORM ON IT ONCE IT SLOWS DOWN OVER THE WESTERN CARIBBEAN ON THU AS EXPECTED...BUT MAY NOT OCCUR. WILL FORECAST THE WAVE TO REACH TO 83W BY FRI MORNING WITH THE LOW PRES AT 15N83W 1008 MB...THEN BEGIN TO MOVE INTO THE GULF OF HONDURAS LATER ON FRI...REACHING TO NEAR 16N87W 1006 MB BY SAT MORNING AND INLAND LATER ON SAT. THIS SYSTEM MAY VERY WELL WEAKEN BEFORE MOVE INLAND. FOR THIS FORECAST WILL FOREST A BRIEF PERIOD OF HIGHER WINDS AND SEAS AS IT MOVES THROUGH THE GULF OF HONDURAS FRI. TROPICAL N ATLC W OF 55W... SCATTERED SHOWERS AND TSTMS ARE CONFINED TO S OF 15N THIS AFTERNOON...BUT HAVE WEAKENED OVER THE PAST FEW HOURS. AN ASCAT PASS FROM NEAR 14 UTC THIS MORNING SHOWED NE-E 20 KT WINDS N OF ABOUT 16N...AND MUCH LIGHTER WINDS ELSEWHERE FROM NE-E TO 10N...AND E-SE S OF 10N WITH SPEEDS OF 5-10 KT. SEAS ARE 6-8 FT N OF 16N...AND 4-6 FT S OF 16N. NEXT MAJOR CHANGES TO AFFECT THIS ZONE WILL BE SEEN WHEN A LARGE E ATLC TROPICAL WAVE AND ASSOCIATED LOW PRES SYSTEM ENTER THE ZONE ON SAT. IT IS FORECAST TO THEN REACH TO NEAR 16N61W SUN...AND TO NEAR 18N66W PER THE AFTERNOON HPC/NHC MEDIUM RANGE CONFERENCE CALL. THESE POINTS ARE A LITTLE SLOWER THAN 12 UTC GFS MODEL RUN. THIS FEATURE WILL HAVE MAJOR IMPLICATIONS ON WINDS AND SEAS AS ACROSS MUCH OF THE ZONE WITH INCREASING TRENDS ON WIND SPEEDS AND SEA HEIGHTS. SOUTHWEST N ATLC... THE PRELIMINARY 18 UTC SURFACE ANALYSIS HAS A WEAK RIDGE ALONG 28N E OF 74W...WHILE A DISSIPATING SURFACE TROUGH EXTENDS FROM THE NW BAHAMAS TO E OF CENTRAL FLORIDA. A WEAKENING STATIONARY FRONT EXTENDS FROM 31N78W TO NE FLORIDA. ASCAT DATA ALONG WITH BUOYS HINTED AT RELATIVELY LIGHT WINDS THROUGHOUT...EXCEPT S OF 23N E OF THE SE BAHAMAS WHERE A TIGHT PRES GRADIENT CREATED BETWEEN THE RIDGE AND THE TROPICAL WAVE IN THE EASTERN CARIBBEAN SEA IS ALLOWING FOR NE-E WINDS OF 20 KT AND SEAS OF 7-9 FT PER A FEW SHIP OBSERVATIONS. SEAS ARE IN THE 2-4 FT RANGE E OF 75W...EXCEPT S OF 23N WHERE SEAS ARE UP TO 8 FT...AND SW OF THE BAHAMAS WHERE LOWER SEAS IN THE 1-2 FT ARE NOTED. THE FORECAST THROUGH THE PERIOD HAS THE STATIONARY FRONT DISSIPATING THROUGH THU. THE RIDGE WILL LIFT N TO 30N THROUGH THU. THE MAIN CHANGES WITH RESPECT TO WINDS AND SEAS ARE EXPECTED TO MATERIALIZE IN THE SE WATERS AS A TROPICAL WAVE WITH POSSIBLE LOW PRES MOVES THROUGH THE NE CARIBBEAN SEA AND OVER PORTIONS OF THE FAR SE WATERS OF THE ATLC. WINDS AND SEAS ARE FORECAST TO INCREASE OVER THE FAR SE WATERS ON SUN AND MON FOR NOW...BUT THIS MAY CHANGE TO SOME EXTENT PENDING OUTCOME OF EVOLUTION AND FUTURE TRACK OF THIS SYSTEM. STAY TUNED TO THE LATEST INFORMATION ON THE TROPICS CONCERNING THIS SYSTEM. WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE