000
AGXX40 KNHC 290741
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
341 AM EDT MON APR 29 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: AVERAGE CONFIDENCE WITH A GFS/ECMWF BLEND
OVERALL...EXCEPT STRAIT GFS OVER WESTERN GULF LATE IN THE PERIOD TO
CAPTURE EXPECTED GALES.

RIDGING PERSISTS FROM A 1027 MB HIGH OFF NEW ENGLAND...DOWN THE
EASTERN SEABOARD...ACROSS THE FLORIDA PENINSULA TO THE TEXAS
COAST. A TROUGH REMAINS ANCHORED OVER THE WESTERN YUCATAN. BUOY
AND SCATTEROMETER DATA SHOW MODERATE TO FRESH E TO SE FLOW OVER
THE SE GULF THIS MORNING. SEAS ARE RUNNING 2 TO 4 FT
OVERALL...WITH SLIGHTLY HIGHER SEAS OVER THE SE GULF. ALOFT...A
MID/UPPER TROUGH FROM THE OHIO VALLEY TO TEXAS IS DIGGING INTO THE
EASTERN PORTION OF THE NATION. MODEL CONSENSUS IS CONSISTENT
SHOWING A MID LEVEL LOW CUTTING OFF OVER LOUISIANA AND EAST TEXAS
TUE...SUPPORTING A WEAK TROUGH ALONG THE NORTHERN GULF COAST. THE
MAIN IMPACT WILL BE AREAS CONVECTION OVER THE COASTAL WATERS
THROUGH MID WEEK. THIS FEATURE WILL LIFT OUT AHEAD OF A DEEP LAYER
TROUGH DIGGING INTO THE PLAINS WITH AN ATTENDANT COLD FRONT
PUSHING INTO THE NW GULF WATERS BY LATE THU. 00Z GFS AND 12Z ECMWF
REMAIN IN DECENT AGREEMENT WITH THE TIMING OF THE FRONT. GIVEN THE
COLD AIR BEHIND THE FRONT AND THE RELATIVELY WARM WATERS OVER THE
WESTERN GULF...IT IS LIKELY THAT STRONG GRADIENT FLOW WILL MIX TO
THE SURFACE OVER THE FAR WESTERN GULF FRI. THE PAST TWO RUNS OF
THE GEFS INDICATE UP TO 40% PROBABILITIES FOR GALES BY FRI MORNING
NEAR TAMPICO...BUT HAVE DROPPED GALES FARTHER SOUTH OFF THE
VERACRUZ COAST IN GMZ023. THIS IS PRESUMABLY DUE TO HIGH SUN
ANGLES AND BETTER AIRMASS MODIFICATION. GRIDS OVER THE WESTERN
GULF FOLLOW OPERATIONAL GFS GUIDANCE WITH GFS/ECMWF BLEND
ELSEWHERE. LOOKING AHEAD TO THE WEEKEND...THE FRONT SAGS SE AND
STALLS OVER THE SE GULF BY SAT. WINDS AND SEAS DIMINISH RAPIDLY
FROM W TO E AS HIGH PRES BUILDS OVER THE NW GULF COASTAL AREA.

...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W... MODEL PREFERENCE: GFS/ECMWF BLEND WITH HIGH
CONFIDENCE AS MODELS IN CLOSE AGREEMENT THROUGH DAY 6.

HIGH PRES N OF REGION MAINTAIN MODERATE TO FRESH BREEZE ACROSS
TROPICAL N ATLC AND CENTRAL CARIBBEAN WITH GENTLE TO MODERATE E
FLOW THROUGH MID WEEK. FRESH BREEZE EXPECTED ACROSS GULF OF
HONDURAS TUE THROUGH THU AS RIDGE STRENGTHENS BEFORE DRIFTING E.
LONG PERIOD NE SWELL 6-7 FT SEEP THROUGH ATLC PASSAGES TODAY AND
TONIGHT THEN BEGINNING SUBSIDING THROUGH WED. WINDS DIMINISH
ACROSS THE BASIN LATER IN THE WEEK AS THE HIGH PRES N OF THE AREA
SHIFTS E AND IS REPLACED BY LOW PRES...THUS WEAKENING THE PRES
GRADIENT OVER THE REGION.

...SW N ATLANTIC INCLUDING THE BAHAMAS...
MODEL PREFERENCE: GFS WITH GOOD CONFIDENCE BASED ON COMPATIBILITY 
WITH ENSEMBLE.

WEAK RIDGING IS IN PLACE OVER THE SW N ATLC WATERS THIS
MORNING...WITH GENTLE TO MODERATE RETURN FLOW NOTED N OF 28N W OF
77W...AND MODERATE TO FRESH EASTERLY FLOW ACROSS THE BAHAMAS INTO
THE STRAITS OF FLORIDA. BUOYS AND A 02 UTC ALTIMETER PASS INDICATE
SEAS 6 TO 9 FT IN NE SWELL OVER MUCH OF THE AREA OUTSIDE THE
BAHAMAS. THIS IS SLIGHTLY HIGHER THAN THE MWW3 GUIDANCE IS
INITIALIZES ALTHOUGH IS MORE IN LINE WITH WITH ECWAVE AND UKMET
WAVEGUIDANCE. MODEL GUIDANCE IS IN DECENT AGREEMENT THROUGH
MIDWEEK SHOWING A GRADUAL EASTWARD SHIFT OF THE RIDGE...AHEAD OF A
TROUGH SAGGING SE FROM THE CAROLINAS TO THE OFFSHORE WATERS OF NE
FLORIDA AND N OF GRAND BAHAMA. MODELS ALSO INDICATE A BROAD MID
LEVEL SHEAR AXIS FROM THE CAROLINA COAST THROUGH N FLORIDA THEN W
ACROSS THE NORTHERN GULF COAST. THE ECMWF AND UKMET TREND FARTHER
S WHILE THE GFS IS IN BETTER ALIGNMENT WITH THE GEFS AND EC
ENSEMBLE. BY FRI...THIS FEATURE WEAKENS AND SHIFTS E...AHEAD OF A
NEGATIVELY TILTED TROUGH MOVING INTO THE MISSISSIPPI VALLEY. AGAIN
THE ECMWF AND UKMET REMAIN THE MORE AGGRESSIVE MODELS. SIMILARLY
AT THE SURFACE...THE 00Z GFS FOLLOWS THE GEFS AND EARLIER RUN OF
THE EC ENSEMBLE MEAN BETTER THAN THE OPERATIONAL ECMWF WHICH
TRENDS MORE WITH THE UKMET AS FASTER AND MORE AGGRESSIVE WITH THE
DEVELOPMENT OF THE LOW PRES. AS A RESULT FORECAST FOLLOWS MORE
CONSERVATIVE GFS ATTM.

.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...GALE CONDITIONS EXPECTED FRI.
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 CHRISTENSEN. NATIONAL HURRICANE CENTER.