000 AGXX40 KNHC 151901 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT MON AUG 15 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... LATEST SURFACE ANALYSIS SHOWS A WEAK 1015 MB HIGH CENTERED OVER THE NW GULF NEAR 27N94W WITH A RIDGE NW TO NE TEXAS AND ANOTHER SE TO THE FAR SE PORTION. THIS FEATURE WILL CONTINUE TO BE THE RULING FEATURE ACROSS THE GULF THROUGH EARLY THU. THE PRELIMINARY 18 UTC SURFACE ANALYSIS SHOWS A WEAKENING COLD FRONT EXTENDING FROM NE FLORIDA SW TO JUST SE OF LOUISIANA WITH SCATTERED SHOWERS AND TSTMS S OF IT TO NEAR 26N. A WEAK TROPICAL WAVE IS OVER THE SW GULF AND BAY OF CAMPECHE ALONG 95W MOVING W AT 10-15 KT. CURRENT AND RECENT BUOY OBSERVATIONS ELSEWHERE ACROSS THE GULF SHOW LIGHT W-NW WINDS TO THE W OF FRONT TO 93W...AND LIGHT SW-W WINDS S OF THE FRONT TO 26N. WINDS OVER THE REMAINDER OF THE AREA ARE GENERALLY SE-S 5-10 KT. SEAS ARE IN THE RANGE OF 1-2 FT THROUGHOUT...EXCEPT IN THE SW ZONE WHERE SEAS OF 2-3 ARE FOUND IN A SMALL POCKET FROM 20N-22N BETWEEN 92W-94W. THE HIGH WILL REFORM AS A RIDGE ROUGHLY ALONG 28N LATER ON THU THROUGH SAT...WHILE THE COLD FRONT MOVES SLOWLY S THROUGH TUE NIGHT...THEN IS FORECAST TO BECOMING STATIONARY AND DISSIPATE TROUGH LATE THU. THE TROPICAL WAVE WILL MOVE WESTWARD INTO MEXICO BY TUE MORNING. WINDS AND SEAS THROUGHOUT WILL VARY VERY LITTLE THROUGH FRI... WITH THE EXCEPTION OF POSSIBLE HIGHER WINDS AND SEAS NEAR SHOWERS AND TSTMS. CARIBBEAN SEA... LATEST ASCAT DATA ALONG WITH OBSERVATIONS SHOW THAT WINDS HAVE DIMINISHED QUITE SUBSTANTIALLY OVER MUCH OF THE CARIBBEAN SINCE YESTERDAY. THIS IS DUE TO WEAKENING ATLC HIGH PRES ALLOWING FOR THE PRES GRADIENT TO SLACKEN. 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 OCCURRING. FORESEEABLE CHANGES TO THE WINDS AND SEAS IN THE CARIBBEAN WILL BE ATTRIBUTED TO A TROPICAL WAVE CURRENTLY JUST E OF THE AREA NEAR APPROACHING THE WINDWARD ISLANDS. THE WAVE IS PRECEDED NUMEROUS SHOWERS AND TSTMS OUT AHEAD IT...AND MOVING RAPIDLY INTO THE FAR EASTERN CARIBBEAN AT THIS TIME. GLOBAL MODEL RUNS FROM 12 UTC THIS MORNING ARE PRETTY MUCH IN CONSENSUS AGREEMENT IN TRACKING THE WAVE WNW THROUGH THE CARIBBEAN WHILE SLOWING DOWN SOME THROUGH TUE NIGHT...AND WITH NO LOW DEVELOPMENT. HOWEVER...THE NOGAPS SHOWS LOW PRES DEVELOPING ON THE WAVE IN THE EASTERN CARIBBEAN WED...WHILE THE GFS RUN NOW ALSO SHOWS LOW PRES FORMING ON THE WAVE BUT BRIEFLY ON TUE. FOR THIS FORECAST WILL USE MODEL CONSENSUS WITH RESPECT TO TRACK AS ALSO DISCUSSED IN THE HPC/NHC MEDIUM RANGE GUIDANCE GUIDANCE...FOR FORECAST POINTS FOR THE WAVE THROUGH DAYS 5. WILL FOREAST WAVE TO NEAR 75W BY THU...TO NEAR 82W FRI AND TO NEAR 86W...AND HOLD OFF ON MENTION OF LOW PRES FORMING FOR NOW. THE MAIN ISSUE WITH THIS WAVE FOR THE NEAR AND MEDIUM TERM FORECAST WILL BE A TIGHT PRES GRADIENT TO ITS N ALLOWING FOR NE-E 20 KT...AND GUSTY WINDS WITH HIGH SEAS IN AND NEAR THE NUMEROUS SHOWERS AND TSTMS AHEAD OF IT. TROPICAL N ATLC W OF 55W... A STRONG TROPICAL WAVE ALONG 58W/59W S OF 17N IS MOVING W 17 KT. NUMEROUS SHOWERS AND TSTMS WITH GUSTY WINDS ARE LOCATED FROM 13N016N W OF 56W. AN ASCAT PASS FROM 13 UTC THIS MORNING SHOWED NE-E 20 KT WINDS N OF THE WAVE WITH SEVERAL RAIN FLAGGED VECTORS OF 25 KT. WINDS WILL DIMINISH THROUGH TUE MORNING AS THE WAVE MOVES INTO THE EASTERN CARIBBEAN SEA. ELSEWHERE WINDS ARE NE-E 10-15 KT N OF 15N...AND E-SE 10-15 KT S OF 15 KT. WINDS OVER THE WESTERN PORTION WILL DIMINISH TO THESE SPEEDS BY WED. SOUTHWEST N ATLC... THE PRELIMINARY SURFACE ANALYSIS HAS A WEAK RIDGE NOW ALONG 24N AND E OF 68W...WHILE A SURFACE TROUGH EXTENDS FROM 23N71W TO EASTERN CUBA. SATELLITE IMAGERY AND MODEL GUIDANCE SHOWS A WEAKENED DEEP LAYER TROUGH JUST OFF THE SE U.S. COAST THAT IS EXPECTED TO AMPLIFY THROUGH TUE. TROPICAL STORM GERT IS CONTINUING TO PULL AWAY THE NE OF THE NE CORNER OF THE AREA EARLY THIS AFTERNOON. A WEAK FRONTAL TROUGH...SUPPORTED BY THE UPPER TROUGH...IS OVER THE FAR NW WATERS EARLY THIS AFTERNOON. ASCAT DATA ALONG WITH BUOYS HINTED AT RELATIVELY LIGHT WINDS THROUGHOUT. SEAS ARE IN THE 3-5 FT RANGE...EXCEPT SW OF THE BAHAMAS WHERE LOWER SEAS IN THE 1-2 FT ARE NOTED. THE FORECAST THROUGH THE PERIOD HAS THE FRONTAL TROUGH STALLING AND SLOWLY DISSIPATING THROUGH WED. HIGH PRES WILL THEN BUILD ALONG 28N THROUGH FRI. A TROUGH FROM 24N69W TO EASTERN CUBA WILL TRACK WNW ACROSS THE SE AND CENTRAL BAHAMAS THROUGH TUE NIGHT... THEN REACH THE NW BAHAMAS WED BEFORE DISSIPATING. E-SE WINDS TO BRIEFLY 20 KT MAY MATERIALIZE BEHIND THE TROUGH S OF ABOUT 22N. A RIDGE WILL THEN BUILD ALONG 29N IN THE WAKE OF THIS SYSTEM ON WED...THEN SHIFT SLIGHTLY N THU THROUGH SAT. 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