000 AGXX40 KNHC 201858 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 255 PM EDT SUN MAY 20 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE 12 UTC SURFACE ANALYSIS SHOWS A PERSISTENT TROUGH THAT EXTENDS FROM ALONG THE E COAST OF THE YUCATAN PENINSULA EXTENDING NNE TO THE FAR SE WATERS JUST N OF THE YUCATAN CHANNEL. ELSEWHERE A RIDGE EXTENDS FROM THE U.S. E COAST SW INTO THE FAR NORTHERN GULF. LATEST AND CURRENT SHIP...BUOYS...OIL PLATFORMS...SHOW RELATIVELY LIGHT TO GENTLE WINDS PREVAILING OVER MUCH OF THE GULF WITH SEAS IN THE RANGE OF 2-4 FT. IN THE SRN PORTIONS OF THE MIDDLE AND WRN GULF AND ALSO CENTRAL AND SRN PORTIONS OF THE ERN GULF NE-E WINDS 15-20 KT ARE NOTED BY THE BUOYS AND A FEW SHIPS IN THOSE AREAS WITH SEAS OF 2-4 FT...EXCEPT 4-5 FT S OF 25N BETWEEN 87W AND 92W. MODELS REMAIN IN FAIRLY GOOD AGREEMENT FOR THE FORECAST PERIOD. THE SURFACE TROUGH WILL CONTINUE TO EXTEND INTO THE FAR SE GULF WATERS FROM THE WESTERN CARIBBEAN THROUGH THE PERIOD. MODELS SHOW THAT THE RIDGE REDEVELOPS AS A HIGH CENTER IN THE FAR NW GULF... THEN SHIFTS EWD TO THE CENTRAL GULF BY WED AND TO THE FAR NE GULF THU AND FRI. THE ONLY UNCERTAINTY IN THE FORECAST WILL BE IN THE MEDIUM TO LONG TERM PERIODS AT WHICH TIMES THE GLOBAL MODELS SUGGEST THAT LOW PRES FORMS ALONG THE TROUGH IN THE WRN CARIBBEAN AND TRACKS NE. HOWEVER...GENERAL CONSENSUS AMONG THE MODELS WITH THE EXCEPTION OF THE NOGAPS IS THAT IT SHOULD REMAIN E OF THE SE GULF AND MOVE ACROSS WRN CUBA WED. THE NOGAPS HAS BEEN CONSISTENTLY SHOWING A LOW THAT QUICKLY TRACKS NE FROM THE ERN YUCATAN PENINSULA TUE TO ACROSS THE YUCATAN CHANNEL AND OVER THE FAR SE GULF WATERS TUE NIGHT AND TO ACROSS S FLORIDA EARLY WED. WILL FOLLOW THE CONSENSUS OF THE MODELS FOR THIS FORECAST PERIOD. IT IS POSSIBLE THAT THE PRES GRADIENT MAY INCREASE SLIGHTLY IN THE FAR SE GULF TUE THROUGH WED AS THE RESULT OF POSSIBLE LOW PRES PASSING TO THE E OF THE AREA. ELSEWHERE...EXPECT LIGHT TO MODERATE WINDS OVER THE NORTHERN GULF WATERS WITH MODERATE TO FRESH WINDS PREVAILING OVER THE SOUTHERN GULF WATERS. SEAS GENERALLY WILL BE 1 TO 3 FT OVER THE NORTHERN WATERS...AND 2 TO 4 FT OVER THE SOUTHERN WATERS THROUGH THE PERIOD EXCEPT POSSIBLY HIGHER IN THE FAR SE PORTION PENDING OUTCOME OF LOW PRES TRACK FROM W CARIBBEAN SEA. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... A BROAD TROUGH CONTINUES ALONG THE E COAST OF THE YUCATAN PENINSULA WITH A WEAK 1009 MB LOW AT NEAR 20N87W. A SURFACE RIDGE PREVAILS N OF THE REMAINDER OF THE AREA. LATEST OBSERVATIONS INDICATE MODERATE E-SE WINDS OVER THE WESTERN CARIBBEAN AROUND THE TROUGH WITH SEAS 4 TO 5 FT AND MODERATE TO FRESH TRADES OVER THE CENTRAL AND EASTERN CARIBBEAN AS WELL AS THE TROPICAL N ATLC WATERS WITH SEAS 6 TO 8 FT. THE EXCEPTION IS IN THE S CENTRAL CARIBBEAN WHERE A LARGE FETCH OF NE-E 20-25 KT WINDS IS RESULTING IN SEAS OF 8-10 FT THERE. LATEST MODEL RUNS SUGGEST THAT THE TROUGH WILL GRADUALLY SHIFT EASTWARD THROUGH WED...THEN MOVE BACK W TOWARDS THE END OF THE FORECAST PERIOD. THE ONLY QUESTION MARKS APPEAR WITH RESPECT TO NEW LOW PRES THAT MODELS SUGGEST FORMS ALONG THE TROUGH AND TRACKS NEWD. WILL WAIT FOR MORE DEFINITIVE MODEL SOLNS ON THIS ASPECT OF THE FORECAST BEFORE BEING MORE SPECIFIC IN THE FORECAST WITH LOW FEATURE. IN ANY EVENT...PLENTY OF ATMOSPHERIC MOISTURE AND INSTABILITY ASSOCIATED WITH THE BROAD TROUGH WILL CONTINUE TO RESULT IN NUMEROUS SHOWERS AND TSTMS OVER MUCH OF THE WRN AND CENTRAL CARIBBEAN THROUGH THE PERIOD. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... MINIMAL TROPICAL STORM ALBERTO IS JUST N OF THE FAR NW WATERS. A TROUGH TO THE E OF IT EXTENDS 31N76W SW TO S FLORIDA. ANOTHER MORE PROMINENT TROUGH IS E OF THE 1ST TROUGH FROM 31N74W TO EASTERN CUBA. AN ASCAT PASS FROM THIS MORNING VALID 1516 UTC SHOWED NORTHERLY WINDS W OF THE 1ST TROUGH AXIS N OF 30N. A SURFACE RIDGE EXTENDS ALONG 28N E OF 70W. FRESH 20 KT WINDS PREVAIL E OF 70W WITH LIGHT TO GENTLE BREEZE PREVAILING OVER THE REMAINDER OF THE AREA. THE LAST NHC ADVISORY VALID 15 UTC FORECASTS ALBERTO TO MOVE SLOWLY SW TO NEAR 31.2N 79.7W EARLY TONIGHT...THEN BEGIN TO TRACK BACK NE MON MORNING TO NEAR 31.4N 79.1W AS A MINIMAL TROPICAL STORM AND TO NEAR 32.N 77.6W BY MON EVENING. BASED ON THIS TRACK...TROPICAL STORM CONDITIONS ARE POSSIBLE FOR A SHORT WHILE N OF 30N FROM NEAR 79W TO NEAR 80W TONIGHT AND INTO MON. SO A TROPICAL STORM WARNING CONTINUES IN EFFECT FOR THOSE WATERS THROUGH MON MORNING. WINDS ARE EXPECTED TO DIMINISH BELOW TROPICAL STORM FORCE EARLY MON AFTERNOON OR SOONER IF ALBERTO WEAKENS EARLIER THAN ANTICIPATED. ELSEWHERE...WEAK RIDGING WILL PREVAIL OVER THE AREA THROUGH THE PERIOD. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE) GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. ATLANTIC... .AMZ111...TROPICAL STORM WARNING N OF 30N W OF 79W... FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE