000 AGXX40 KNHC 130637 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 237 AM EDT WED APR 13 2016 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: 00Z GFS BLENDED WITH THE OFFICIAL WIND FORECAST. THE 06Z NWPS BLENDED WITH THE OFFICIAL WAVE FORECAST. MEDIUM CONFIDENCE. THE MODELS AGREE ON WINDS REMAINING BELOW A FRESH TO STRONG BREEZE WITH THE WEAK COLD FRONT MEANDERING AROUND THE NORTHERN GULF COASTAL PLAIN THROUGH TONIGHT. THE FRONT IS EXPECTED TO MOVE S THROUGH THE E GULF THU...WITH A FRESH TO STRONG BREEZE DEVELOPING IN THE NE GULF BY THU NIGHT BEHIND THE FRONT. THE MODELS BEGIN TO DIVERGE BY FRI NIGHT WITH THE GENERAL UPPER PATTERN. THE 00Z GFS CARRIES STRONGER SHORTWAVE ENERGY THROUGH THE SE UNITED STATES FRI NIGHT THROUGH SAT NIGHT THAN THE 12Z/12 ECMWF AND IS FASTER TO DRAG THE FRONT S. THE 00Z UKMET AND 18Z GEFS MEAN SIDE WITH THE GFS SOLUTION HERE AT THAT TIME. GETTING INTO EARLY NEXT WEEK...THE MODELS AGREE ON PHASING THIS ENERGY INTO THE POSITIVELY TILTED UPPER TROUGH OVER THE SW N ATLC AND BUILDING THE RIDGING OVER THE CENTRAL GULF AHEAD OF THE H5 TROUGHING MOVING INTO THE SOUTHERN PLAINS. THE EC ENS MEAN HEDGES TOWARD THE 00Z GFS SOLUTION BY PHASING THE ENERGY MORE SLOWLY AND HOLDING THE H5 TROUGH MORE POSITIVELY TILT THAN THE 12Z/12 ECMWF. THE MODEL CONSENSUS IS MORE LIKE THE GFS. THESE DIFFERENCES ALOFT IMPACT THE STRENGTH OF THE PRES GRADIENT ACROSS THE NORTHERN GULF THU NIGHT THROUGH SUN NIGHT. THEREFORE...FEEL COMFORTABLE LEANING TOWARD THE GFS TO ADJUST THE GRIDS. ELSEWHERE...THE 00Z GFS SHOWS A FRESH TO STRONG BREEZE DEVELOPING ALONG THE NW COAST OF THE YUCATAN PENINSULA THIS AFTERNOON AND SLOWLY DISSIPATING AS IT MOVES W WITH THE THERMAL TROUGH OVERNIGHT. THE GFS KEEPS WINDS AT OR BELOW 20 KT AS THE COLD FRONT MOVES S THROUGH THE E GULF AND TROUGHING LINGERS INTO THE WEEKEND. A FRESH TO STRONG BREEZE SHOULD RETURN HERE ON SUN. THE GFS GENERALLY HANDLES THIS DIURNAL PATTERN BETTER THAN THE OTHER MODELS...SO THE GFS IS PREFERRED THROUGH THU. THE 06Z NWPS INCORPORATES THE FAVORED WIND FIELD AND WILL BE USED TO ADJUST THE GRIDS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH THE OFFICIAL WIND FORECAST. THE 06Z NWPS BLENDED WITH THE OFFICIAL WAVE FORECAST. HIGH CONFIDENCE. AS STATED ABOVE...THE 00Z GFS AND 00Z UKMET ARE FAVORED OVER THE 12Z/12 ECMWF WITH THE GENERAL PATTERN N OF THE AREA...ESPECIALLY BY THU NIGHT. THE RIDGING BUILDING OVER THE GULF SHOULD ALLOW A FRESH BREEZE TO DEVELOP ALONG THE N COAST OF HONDURAS FRI NIGHT AND INCREASE TO FRESH TO STRONG SAT NIGHT AND SUN NIGHT AS THE PRES GRADIENT BUILDS. IN THE TROPICAL ATLC...THE PREFERENCE FOR WIND HAS BEEN HEDGED TOWARD THE 00Z GFS. SEE THE SW N ATLC SECTION BELOW FOR DETAILS CONCERNING THE TROUGHING N OF THE NE CARIBBEAN. THIS TROUGHING WILL WEAKEN THE WINDS ACROSS THE TROPICAL ATLC. THE ABSENCE OF ANY SIGNIFICANT LONG-PERIOD SWELL IN THE ATLC PROVIDES MORE CONFIDENCE IN USING THE NWPS AND MWW3 TO ADJUST THE SEAS AS THE ECMWF IS GENERALLY BETTER WITH LONG-PERIOD SWELL. SINCE THE 06Z NWPS INCORPORATES THE FAVORED WIND FIELD...WILL USE IT TO ADJUST THE GRIDS. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS BLENDED WITH OFFICIAL WIND FORECAST. 00Z MWW3 BLENDED WITH OFFICIAL WAVE FORECAST. MEDIUM CONFIDENCE. AS STATED ABOVE...THE LACK OF SIGNIFICANT LONG-PERIOD SWELL IN THE ATLC HAS BOOSTED CONFIDENCE IN THE MWW3/NWPS SOLUTIONS EARLY IN THE FORECAST PERIOD. WINDS ARE EXPECTED TO REMAIN WELL BELOW ADVISORY CRITERIA OVER MUCH OF THE AREA...EXCEPT THE FAR NW WATERS...THROUGH THU. BEGINNING THU...THE 12Z/12 ECMWF STRAYS FROM THE MODEL CONSENSUS BY CARRYING A LESS AMPLIFIED SHORTWAVE SYSTEM FROM THE WESTERN ATLC THROUGH THE MISSISSIPPI VALLEY THAN THE MODEL CONSENSUS AND PHASES IT MORE QUICKLY...ALLOWING THE ECMWF TO HAVE A LESS POSITIVELY-TILTED UPPER TROUGH OVER THE SW N ATLC THAN THE DETERMINISTIC MODEL AND ENS CONSENSUS. THE 00Z GFS AND UKMET ARE IN AGREEMENT ON DEVELOPING A COASTAL BOUNDARY OFF THE SOUTHEASTERN COAST...PRIMARILY N OF THE AREA...THAT WILL FUNNEL FRESH TO STRONG NE WINDS IN THE JAX COASTAL ZONES WHILE THE ECMWF CARRIES WEAKER FLOW UNTIL IT DEVELOPS LOW PRES IN THIS AREA FRI. THE GFS AND UKMET SHOW AN INVERTED TROUGH ALONG THE FL E COAST...BUT DO NOT DEVELOP A SURFACE LOW FRI LIKE THE ECMWF. THE ECMWF APPEARS TO SUFFER FROM GRID-SCALE FEEDBACK PROBLEMS HERE AS IT GENERATES OVER 5 INCHES OF PRECIPITATION NEAR THE LOW FROM 18Z FRI TO 00Z SAT. HOWEVER...THE GFS ALSO SEEMS TO HAVE SOME GRID- SCALE ISSUES HERE. THE FORECAST HEDGES TOWARD THE MORE GFS AS IT APPEARS TO HAVE LESS OF AN ISSUE WITH FEEDBACK AND AGREES WITH THE CONSENSUS WHICH DOES NOT PLACE A LOW HERE. FARTHER E...THE GFS LOOKS LIKE A CONSENSUS OF THE MODELS AND ENS MEANS WITH THE MEAN POSITION OF THE LOW PRES IN THE VICINITY OF BERMUDA THIS WEEKEND. THE 18Z GEFS MEAN IS FARTHER W WHILE THE EC AND EC ENS MEAN ARE TO THE E. HOWEVER...THE EC ENS MEAN LEANS MORE TOWARD THE GFS POSITION AND IS LESS AGGRESSIVE WITH THE RIDGING TO ITS NE THAN THE ECMWF...MORE LIKE THE GFS. THE GFS WAS USED TO ADJUST THE GRIDS. THE MWW3 WAS USED TO ADJUST THE WAVE GRIDS EARLY...BUT IT WILL BE HEDGED TOWARD THE 06Z NWPS WHICH ADOPTS THE FAVORED WIND FORECAST. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER SCHAUER. NATIONAL HURRICANE CENTER.