Marine Interpretation Message
Issued by NWS

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000
AGXX40 KNHC 271819
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
119 PM EST SAT DEC 27 2014

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: GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST.
LATEST MWW3 AND TAFB-NWPS USED FOR WAVE HEIGHTS. MEDIUM
CONFIDENCE.

THE 00Z ECMWF HAS BACKED OFF WITH THE STRENGTH OF THE WINDS
BEHIND THE COLD FRONT TONIGHT THROUGH SUN...DELAYING WINDS
REACHING 25 KT UNTIL 18Z SUN WHILE THE 12Z GFS SHOWS WINDS THAT
STRONG AS SOON AS THE FRONT MOVES OVER THE 72 DEGREE WATERS IN THE
NW GULF TONIGHT AND CONTINUES TO SHOW WINDS TO 30 KT ALONG THE
COAST OF VERACRUZ SUN AFTERNOON. THE FRONT APPEARS TO BE
STRONG...WITH THE OBSERVATION IN SAN ANTONIO DIPPING 15 DEGREES IN
THE LAST 2 HOURS AND WINDS INCREASING FROM 5 KT AHEAD OF THE FRONT
TO 20 KT BEHIND IT. THE STRONGER SOLUTION SEEMS MORE LIKELY...SO
THE GFS WAS USED TO ADJUST THE FORECAST. THE GFS IS SLIGHTLY
FASTER TO MOVE THE FRONT EASTWARD THROUGH THE NE GULF AS IT
WEAKENS SUN NIGHT AND MON. THE MODELS HAVE HAS A HARD TIME
SETTLING ON A FORECAST WITH THIS FRONT...SO CONFIDENCE IS NOT
EXTREMELY HIGH. BOTH THE GFS AND ECMWF SHOW HIGH PRES BUILDING IN
EARNEST BEHIND THE FRONT TUE AND WED...WITH THE GFS SLIGHTLY
STRONGER WITH WINDS OVER THE N GULF WED. BY WED NIGHT...BOTH
MODELS SHOW TROUGHING BUILDING OVER THE W GULF AND INCREASE WINDS
TO 20-25 KT IN THE NW PORTION. THERE IS ALSO GOOD AGREEMENT ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE TEXAS COAST THU. THE GFS
SOLUTION IS NOT THAT FAR OFF THE ECMWF HERE...SO IT WAS USED
THROUGHOUT THE FORECAST PERIOD TO ADJUST THE WINDS. THE MWW3 HAD
LARGER SEAS BEHIND THE FRONT TONIGHT THROUGH MON NIGHT THAN THE
NWPS AND LOOKS MORE REASONABLE COMPARED TO THE PREFERRED STRONG
WIND SPEEDS OF THE GFS. BEYOND MON NIGHT...THE NWPS COMES INTO
BETTER AGREEMENT WITH THE MWW3 AND WAS USED TO ADJUST THE
FORECAST.

...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL
FORECAST. LATEST TAFB-NWPS USED FOR WAVE HEIGHTS IN THE CARIBBEAN
WITH THE MWW3 ALSO USED IN THE BLEND IN THE TROPICAL N ATLC. HIGH
CONFIDENCE.

BAGGY HIGH PRES OVER THE BAHAMAS HAS ALSO INCREASED THE PRES
GRADIENT IN THE LEE OF CUBA AND IN THE WINDWARD PASSAGE WHERE
20-25 KT WINDS ARE CURRENTLY FOUND. WINDS IN THE LEE OF CUBA ARE
EXPECTED TO DIMINISH BELOW A STRONG BREEZE LATER TODAY AS HIGH
PRES ORGANIZES NE OF THE AREA WHILE WINDS IN THE WINDWARD PASSAGE
WILL REMAIN A FRESH TO STRONG BREEZE THROUGH SUN MORNING. THE
STRONGER...HIGHER RESOLUTION GFS WAS USED FOR THE WIND FORECAST
HERE...WITH WINDS BUMPED UP A BIT AS IT HAS A LOW BIAS IN ENHANCED
NE FLOW EVENTS HERE. THE NWPS SEAS WERE HIGHER THAN THE MWW3 HERE
AND MORE CLOSELY MATCHED THE WINDS. AS THE HIGH MOVES E...THE
AREA OF WINDS AT OR ABOVE ADVISORY CRITERIA CENTERED OVER THE
CENTRAL CARIBBEAN WILL SHRINK. THE GFS SEEMS REASONABLE AND
GENERALLY DOES BEST WITH THE STRONGER WINDS ALONG THE COAST OF
COLOMBIA WHERE IT SHOWS 30 KT EVERY MORNING THROUGH THE PERIOD. IN
THE TROPICAL N ATLC...NE SWELL HAS BROUGHT SEAS OVER 8 FT TO WATERS
N OF 14N ACCORDING TO AN 1100Z ALTIMETER HAS. SEAS OVER 8 FT WILL
SPREAD OVER THE ENTIRE AREA THROUGH THE WEEKEND. SEAS WILL BE
SLOW TO SUBSIDE HERE. THE NWPS IS STILL SPINNING UP THE SWELL OVER
THE ATLC BASIN AND APPEARS LOW WITH WAVE HEIGHTS ON DAY 1. RELIED
MORE ON THE MWW3 FOR WAVES EARLY IN THE PERIOD. THE MWW3 AND NWPS
ARE IN GOOD AGREEMENT ON SEAS HOVERING IN THE 7-9 FT RANGE INTO
MON AND TUE AND SUBSIDING FURTHER ON WED.

...SW N ATLANTIC S OF 31N W OF 55W INCLUDING THE BAHAMAS...

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL
FORECAST THROUGH WED WITH THE ECMWF ADDED WED NIGHT AND THU.
LATEST TAFB-NWPS AND MWW3 USED FOR WAVE HEIGHTS WITH THE EC WAVE
ADDED WED NIGHT AND THU. MEDIUM CONFIDENCE.

NE SWELL OVER 8 FT OVER WATERS E OF 70W CONTINUES TO SPREAD
SW...CURRENTLY APPROACHING PUERTO RICO AND EXPECTED TO REACH THE
SE BAHAMAS TONIGHT BEFORE GRADUALLY SUBSIDING SUN NIGHT THROUGH
TUE. THE NWPS IS SLOWER TO ADVANCE THE SWELL THAN THE MWW3 FOR THE
FIRST 24 HOURS...BUT THEN IS IN BETTER AGREEMENT WITH THE MWW3.
THE MWW3 WAS RELIED ON FOR ADJUSTING SEAS FOR DAY 1. THE 12Z GFS
AND 00Z ECMWF HAVE COME INTO MUCH BETTER AGREEMENT WITH THE TIMING
OF THE COLD FRONT MOVING OFF THE NE FLORIDA COAST TUE...WITH BOTH
MODELS EXTENDING THE FRONT FROM 31N71W TO CAPE CANAVERAL TUE
EVENING AND WEAKENING THE FRONT WED. LARGER DIFFERENCES COME INTO
PLAY WED NIGHT AND THU WHEN THE WHEN THE GFS BUILDS CONSIDERABLY
STRONGER HIGH PRES N OF THE AREA WHERE THE ECMWF SHOWS A TROUGH AT
THE SURFACE. THE GFS SHOWS A SOLID AREA OF 20 KT NE WINDS OVER N
WATERS WED NIGHT WHILE THE ECMWF GENERALLY SHOWS A GENTLE BREEZE
WITH MORE NORTHERLY FLOW OVER W WATERS. THE UKMET DOES NOT SHOW
GOOD AGREEMENT WITH EITHER MODEL AND THE CORRESPONDING ENS MEANS
LOOK LIKE WEAKER VERSIONS OF THE OPERATIONAL MODEL. A BLEND OF THE
12Z GFS AND 00Z ECMWF SEEMS BEST FOR ADJUSTING THE FORECAST FROM
WED NIGHT ONWARD.

$$

.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.


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