000 AGXX40 KNHC 270749 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 348 AM EDT MON MAY 27 2013 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: MEDIUM CONFIDENCE IN THE 00Z GFS AND MWW3 BLENDED WITH THE OFFICIAL FORECAST THROUGH FRI. FOR THE SECOND DAY IN A ROW...AN ASCAT PASS OVER THE SW GULF HAS COME IN WITH WINDS STRONGER THAN ANY OF THE MODEL INITIAL FIELDS. THE STRONGER GFS SEEMS TO HAVE A BETTER HANDLE ON THE WINDS OFF THE NW COAST OF THE YUCATAN PENINSULA THAN THE REST OF THE GUIDANCE. THE STRONGER GFS ALSO SEEMS TO BE IN BETTER AGREEMENT WITH OBSERVATIONS IN THE STRAITS OF FLORIDA. WILL RELY MOST HEAVILY ON THE GFS EARLY IN THE FORECAST PERIOD. FROM MON NIGHT THROUGH WED...AN UPPER TROUGH IS EXPECTED TO DIG SOUTHWARD THROUGH THE EASTERN GULF AND MOVE INTO FLORIDA. DIFFERENCES IN THE WIND FORECAST OVER THE GULF ARE SMALL THROUGH WED. BY THU...THE GFS CARRIES STRONGER WINDS IN THE SE GULF OF MEXICO THAN THE REST OF THE GUIDANCE AS HIGH PRESSURE BUILDS FROM THE NE AND A STRONGER SURFACE TROUGH BEGINS TO DEVELOP BETWEEN FLORIDA AND THE BAHAMAS. CONFIDENCE IS LOWERED WITH THE EVOLUTION OF THIS TROUGHING AND ITS ASSOCIATED UPPER LOW OVER THE SW N ATLC. HOWEVER...THE PREFERENCE THERE IS TOWARD THE 00Z GFS/MWW3 SOLUTION. A BLEND OF THE 00Z GFS/MWW3 AND THE WEAKER PREVIOUS FORECAST SHOULD HELP TONE THINGS DOWN OVER THE EASTERN GULF COMPARED TO THE RESPECTIVE DETERMINISTIC RUNS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: MEDIUM CONFIDENCE IN GFS AND MWW3 BLENDED WITH PREVIOUS OFFICIAL FORECAST THROUGH TUE...THEN A BLEND THAT INCLUDES THE ECMWF AND EC WAVE WED THROUGH FRI. NONE OF THE MODELS HAVE A GOOD HANDLE ON THE AREA OF FRESH TO STRONG E-NE TRADE WINDS ALONG THE COAST OF COLOMBIA AS SEEN BY THE 0248 UTC ASCAT PASS. THEY ARE ALL TOO WEAK...WITH THE 00Z GFS CLOSEST TO REALITY. SHIP OBSERVATIONS OVER 8 FT HAVE BEEN REPORTED IN THE LAST 6 HOURS IN THIS AREA OF STRONG WINDS. THE MWW3 AND EC WAVE SHOW A SMALLER AREA OF SEAS OVER 8 FT BY 06Z THIS MORNING THAN THE OBSERVATIONS SUGGEST...WITH THE MWW3 CLOSER TO THE OBSERVATIONS. A SLIGHTLY STRONGER VERSION OF THE GFS/MMW3 LOOKS REASONABLE HERE THROUGH TUE. STARTING TUE...AN UPPER TROUGH DIGGING OVER THE EASTERN GULF OF MEXICO WILL INCREASE TROUGHING OVER THE NW CARIBBEAN. BY WED...THE 00Z GFS BUILDS A LARGER AREA OF FRESH EASTERLY WINDS ACROSS THE CENTRAL AND WESTERN CARIBBEAN COMPARED TO THE 00Z ECMWF WHICH BUILDS A LARGER CIRCULATION OF LIGHT TO GENTLE WINDS AROUND LOW PRESSURE IN THE SW CARIBBEAN. THE UKMET AND NAVGEM AGREE MORE WITH THE ECMWF ON THE DEVELOPMENT OF THE WEAK AREA OF LOW PRESSURE...BUT ARE STRONGER THAN THE ECMWF WITH THE WINDS. WITH CONFIDENCE IN ANY ONE MODEL SOMEWHAT SHAKEN HERE AS WELL AS WITH THE EVOLUTION OF THE SYSTEM TO THE N...A BLEND OF THE PREVIOUS FORECAST WITH THE 00Z GFS/MM3 AND 00Z ECMWF/EC WAVE SEEMS PRUDENT FOR WED THROUGH FRI. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: MEDIUM TO CONFIDENCE IN A BLEND OF THE PREVIOUS OFFICIAL FORECAST WITH THE 00Z GFS/MWW3 MON AND FRI...WITH THE 00Z ECMWF AND EC WAVE BLENDED INTO THE MIX TUE THROUGH FRI. NONE OF THE MODELS ARE STRONG ENOUGH WITH THE E-NE WINDS OVER THE BAHAMAS COMPARED TO THE AREA OF FRESH TO STRONG WINDS SEEN IN THE 0250 UTC ASCAT PASS AND FROM SHIP OBSERVATIONS. THE GFS IS THE STRONGEST SOLUTION...BUT STILL REQUIRED BUMPING UP TO MATCH THE OBSERVATIONS. THE MODELS GENERALLY AGREE ON BUILDING MORE EASTERLY WINDS BETWEEN CUBA AND THE BAHAMAS OVERNIGHT MON NIGHT INTO TUE IN RESPONSE TO THE INCREASING PRESSURE GRADIENT BETWEEN BUILDING HIGH PRESSURE TO THE NE AND TROUGHING APPROACHING FLORIDA FROM THE WEST. THIS SURFACE TROUGH IS ASSOCIATED WITH AN UPPER TROUGH DIGGING THROUGH THE EASTERN GULF OF MEXICO LATE MON AND TUE AND STALLING E OF FLORIDA WED THROUGH FRI. THE 00Z GFS HAS BACKED OFF ON THE 30 KT WINDS THE 18Z RUN CARRIED OVER THE BAHAMAS AND IS WEAKER WITH THE SURFACE REFLECTION OF THE TROUGH E OF FLORIDA BY THU WHICH SEEMED TO BE AN ARTIFACT OF GRID-SCALE FEEDBACK. THE 00Z RUN IS IN AGREEMENT WITH THE 00Z ECMWF ON EXPANDING 25 KT WINDS OVER THE BAHAMAS STARTING WED. WITH CONFIDENCE LOWERED IN ANY ONE OPERATIONAL RUN WITH THE EVOLUTION OF THIS SYSTEM...PREFER TO ADD A BLEND OF THE GFS/ECMWF AND THEIR WAVE MODELS INTO THE MIX TUE THROUGH THU. THE GFS AND ECMWF DIVERGE BY FRI WHEN THE ECMWF DEVELOPS A STRONGER TROUGH AND SHIFTS THE STRONG WINDS NORTHWARD LEAVING LIGHT TO GENTLE WINDS BETWEEN THE BAHAMAS AND CUBA FRI. THE UKMET AND NAVGEM AGREE WITH THE GFS BY FRI AND THE GFS/ECMWF ENSEMBLE MEANS SHOW A WEAKER SURFACE TROUGH THAN THE OPERATIONAL ECMWF SUGGESTS ON FRI. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER SCHAUER. NATIONAL HURRICANE CENTER.