000 AGXX40 KNHC 181850 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT FRI MAY 18 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 NRN PORTION OF A SURFACE TROUGH EXTENDS FROM THE NW CARIBBEAN NE TO ACROSS THE SE GULF WATERS. LATEST SHIP...BUOY...CMAN STATIONS...SATELLITE DERIVED WINDS INDICATE MOSTLY LIGHT WINDS PREVAILING ACROSS THE AREA WITH SEAS GENERALLY 2 FT OR LESS. A PARTIAL ASCAT PASS FROM NEAR 16 UTC THIS MORNING CONFIRMED THESE WINDS. AS MENTIONED IN THE PREVIOUS FORECAST...MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE FORECAST PERIOD. HIGH PRESSURE WILL BUILD ACROSS THE AREA PUSHING THE SURFACE TROUGH E OF THE AREA BY SAT...WITH A SURFACE RIDGE PREVAILING JUST N OF THE AREA THROUGH LATE MON BEFORE SHIFTING S TO THE FAR NRN PORTION TUE AND WED. WITH THIS SCENARIO...LIGHT TO MODERATE WINDS CAN BE EXPECTED 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. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... BROAD TROUGHING OVER THE WRN CARIBBEAN CONTINUES TO BE THE MAIN FEATURE OF INTEREST FOR THE CARIBBEAN BASIN. LATEST SURFACE ANALYSIS HAS THE TROUGH EXTENDING FROM THE NE YUCATAN PENINSULA SSE TO A WEAK 1010 MB LOW AT 18N87W AND TO INLAND THE NW PORTION OF HONDURAS. FIRST VISIBLE IMAGERY FROM THIS MORNING AND INTO EARLY THIS AFTERNOON REVEALED A PARTIALLY EXPOSED SWIRL OF LOW CLOUDS WITHIN 60-90 OF THE LOW. SMALL CLUSTERS OF TSTMS ARE WITHIN SE AND S OF THE LOW TO THE COAST OF HONDURAS...AND NEWLY DEVELOPED ONES ARE WITHIN 60 NM TO THE N OF THE LOW. AN OSCAT PASS FROM OVERNIGHT LAST NIGHT REVEALED FRESH TO MODERATE E WINDS IN THE GULF OF HONDURAS...BUT NO EVIDENCE OF A CIRCULATION. ON THE OTHER HAND...THE ASCAT PASS FROM LATE LAST NIGHT...AND FROM NEAR 16 UTC THIS MORNING SHOWED A CYCLONIC CIRCULATION AT 17N87W WITH MODERATE SE-S WINDS WITHIN 60 NM IN THE NE AND E QUADRANTS. A SURFACE RIDGE PREVAILS N OF THE FORECAST. THE 1420 UTC ASCAT PASS FROM THIS MORNING SHOWED FRESH TRADES OVER THE SRN SECTION OF CENTRAL CARIBBEAN...WITH EMBEDDED FRESH TO STRONG TRADES THERE. SHIP WITH CALL LETTER ID "DDSC2" NW OF COLOMBIA AT 12N74W REPORTED NE WINDS OF 25 KT AT 15 UTC THIS MORNING. MODERATE TO FRESH TRADES ELSEWHERE ACROSS THE CARIBBEAN. IT MISSED JUST ABOUT THE ENTIRE TROPICAL N ATLC ZONE WITH THE EXCEPTION OF THE FAR NW PART WHERE MODERATE NE WINDS WERE NOTED. BUOY 41101 AT 14.7N56W IS REPORTING E WINDS OF 20 KT OF OF EARLY THIS AFTERNOON. BASED ON THIS...AND ON THE LATEST SURFACE PRES ANALYSIS...CAN INFER THAT MODERATE NE-E TRADES ARE PRESENT ELSEWHERE ACROSS THE TROPICAL N ATLC WATERS. THE MODELS ARE IN GENERAL AGREEMENT WITH BROAD TROUGHING PREVAILING OVER THE WESTERN CARIBBEAN WATERS THROUGHOUT THE FORECAST PERIOD. THERE ARE SOME DIFFERENCES...HOWEVER...WITH RESPECT TO THE FORECAST PSNS OF THE PRESENT LOW AT 18N87W IN THE MEDIUM TO LONG TERM PERIODS OF THE FORECAST. AFTER SUN...THE GFS FAVORS A NEW LOW THAT DEVELOPS FARTHER E THEN THE PRESENT ON WITH A TRACK ACROSS WRN CUBA TO FAR WRN STRAITS OF FLORIDA BY LATE WED NIGHT. THE 00 UTC FROM LAST NIGHT PRETTY MICH KEEPS THE WEAK LOW RELATIVELY IN THE SAME PLACE AS IT IS TODAY THROUGH WED WITH STILL THE ASSOCIATED AMPLIFYING TROUGH WED. THE UKMET IS SIMILAR TO THE GFS IN TAKING THE LOW IN A GENERAL NNE TRACK MON THROUGH WED...BUT IS MUCH FARTHER TO THE NW KEEPING THE LOW OVER THE SE GULF. THE CANADIAN IS SIMILAR TO THE GFS IN DEVELOPING A LOW FARTHER E MON...THEN TAKING IT NEWD ACROSS CENTRAL CUBA TUE TO NE OF THE BAHAMAS BY LATE TUE NIGHT. BASED ON THESE MODELS DEPICTIONS OF LOW PRES IN THE WRN CARIBBEAN...MY CONFIDENCE LEVEL IS ON THE LOW SIDE WITH RESPECT TO LOW PRES PSNS IN THE LONG TERM OF THE FORECAST...BUT HIGHER IN KEEPING THE BROAD TROUGH OVER THAT LOCATION. I WILL LEAN TOWARDS THE GFS ENSEMBLE N KEEPING A TROUGH OVER THE WRN CARIBBEAN THAT AMPLIFIES THROUGH THE PERIOD SINCE IT APPEARS THAT MORE THAN ONE WEAK LOW MAY IN THIS TROUGH AREA DURING THE FORECAST PERIOD AS THE TROUGH AMPLIFIES. THIS THINKING IS SIMILAR TO THAT OF PREVIOUS FORECASTS. EXPECTED SCATTERED SHOWERS AND TSTMS WITH POSSIBLE GUSTY WINDS TO PERSIST OVER THE WRN CARIBBEAN INTO WED. MODERATE TO FRESH WINDS ARE STILL FORECAST TO BECOME MORE E-SE IN DIRECTION OVER THE MAJORITY OF THE WRN CARIBBEAN AND WRN PORTION OF THE CENTRAL CARIBBEAN SAT THROUGH SUN NIGHT...AND INTO THE EARLY AND MID PORTIONS OF NEXT WEEK AS THE BROAD TROUGH IN THE NW CARIBBEAN AMPLIFIES TO THE NE. MODERATE TO FRESH TRADE TRADES ARE FORECAST TO CONTINUE OVER THE REMAINDER OF THE CARIBBEAN AND TROPICAL N ATLC WATERS THROUGH WED. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... THE 18 UTC PRELIMINARY ANALYSIS HAS A WEAKENING COLD FRONT OVER THE FAR NW PORTION OF THE AREA EXTENDING FROM 31N78W SW TO ACROSS N CENTRAL FLORIDA. LATEST SHIP...BUOY...AND RECENTLY RECEIVED ASCAT DATA SHOW FRESH TO LOCALLY STRONG WINDS PREVAILING TO THE E OF 70W WITH LIGHT TO MODERATE WINDS PREVAILING W OF 70W. VERY DEEP ATMOSPHERIC MOISTURE RESULTING IN NUMEROUS SHOWERS AND SCATTERED TSTMS IS CONFINED TO THE E OF 75W DUE TO A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH AN UPPER LEVEL TROUGH PIVOTING EWD AROUND AN UPPER LEVEL LOW THAT IS JUST SE OF SRN S CAROLINA. THE TROUGH WILL REACH FROM NEAR 31N75W TO NW BAHAMAS BY SAT MORNING AS THE FRONT BECOMES DIFFUSE...AND FROM NEAR 31N74W TO S FLORIDA BY EARLY SUN AFTERNOON WHERE IT WILL THEN STALL AND DISSIPATE THROUGH SUN. THE STRONGEST WINDS WILL GENERALLY CONTINUE E OF 70W WITH LIGHT TO MODERATE WINDS PREVAILING W OF 70W THROUGH THE PERIOD. UNCERTAINTY IN THE LONG TERM PART OF THE FORECAST WILL BE WITH THE FUTURE STATUS OF THE BROAD TROUGH IN THE WRN CARIBBEAN SEA AS ITS FAR NRN EXTENSION WILL MOST PROBABLY BE A FACTOR WITH RESPECT TO UNSETTLED WEATHER CONDITIONS IN THE SW AND PORTION OF THE ATLC BASIN WITH THIS FEATURE ALSO BEING A SOURCE OF CONTINUING TO AID MOISTURE ALREADY PRESENT TO THE E OF 75W. AS MENTIONED ABOVE UNDER CARIBBEAN AND TROPICAL N ATLC... SOME OF THE GLOBAL MODELS SUGGEST THAT LOW PRES MAY TRACK NE FROM THE CARIBBEAN SEA AND ACROSS OR NEAR THE BAHAMAS EARLY NEXT AND TO THE JUST N OF THE AREA BY WED. WILL HAVE TO WAIT FOR FUTURE MODEL RUNS TO SEE IF THEY CONTINUE TO SHOW THIS SCENARIO SETTING UP IN MORE CONSISTENT MANNER BEFORE MAKING MENTION OF IT IN THE FORECAST. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE) GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE