Marine Interpretation Message
Issued by NWS

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AGXX40 KNHC 211751
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
151 PM EDT THU AUG 21 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: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL.
NWPS/MWW3 BLEND USED FOR WAVE PARAMETERS. HIGH CONFIDENCE.

A RIDGE EXTENDS FROM FL BAY TO THE MS DELTA WITH A HIGH PRES
CENTER ALONG THE RIDGE NEAR 28N87W. THIS FEATURE CONTINUES TO
MAINTAIN CONTROL OF THE WEATHER PATTERN OVER THE AREA.THE HIGH
WILL GRADUALLY SHIFT NW ALONG THE RIDGE TO THE N-CENTRAL GULF
TODAY AND TONIGHT...THEN SHIFT FURTHER NW OVER INTERIOR LA ON
FRI...WITH A RIDGE EXTENDING SE TO THE SE GULF WATERS. THE HIGH
WILL SHIFT SE ALONG THE RIDGE AND BACK OVER THE NE GULF OVER THE
WEEKEND AND CONTINUE EARLY NEXT WEEK AS THE RIDGE BECOMES
ALIGNED FROM SW LA TO FL BAY.

VARIABLE 5-10 KT WINDS EXPECTED OVER THE NE GULF WATERS TILL FRI
WHEN THEY BECOME NE AT 5-10 KT. THE LIGHT AND VARIABLE CONDITIONS
WILL DEVELOP AGAIN ON FRI NIGHT AND SAT...THEN BECOME NE ACROSS
THE NE PORTION EARLY MON...AND INTO TUE BY THEN THE GRADIENT MAY
BE TIGHTENING AS A TROPICAL LOW...POSSIBLY A TROPICAL CYCLONE...
CONTINUES NW OVER OR VERY NEAR THE BAHAMAS.

S OF 23N...EXPECT AN EVENING ENHANCEMENT OF 15-20 KT NE WINDS
ALONG THE W COAST OF THE YUCATAN PENINSULA EACH EVENING SETTING
UP AN INVERTED TROUGH OVER THE EASTERN BAY OF CAMPECHE DURING
THE LATE NIGHT HOURS. THE TROUGH WILL SHIFT W ACROSS THE CENTRAL
BAY OF CAMPECHE DURING EACH MORNING...AND LOSE IDENTITY DURING
THE EARLY AFTERNOON HOURS ACROSS THE CENTRAL BAY OF CAMPECHE.

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

MODEL PREFERENCE:  LATEST GFS BLENDED WITH PREVIOUS OFFICIAL
...WEIGHTED MORE TOWARDS THE GFS. NWPS/MWW3/PREVIOUS OFFICIAL BLEND
USED FOR WAVE PARAMETERS. AVERAGE CONFIDENCE W PORTION...LOW
CONFIDENCE E PORTION.

FRESH TO LOCALLY STRONG EASTERLY TRADES WILL CONTINUE ACROSS THE
S-CENTRAL CARIBBEAN THROUGH EARLY FRI. THE TROPICAL LOW PRES
NEAR 15N56W 1009 MB HAS CHANGED LITTLE IN ORGANIZATION DURING THE
PAST SEVERAL HOURS...PARTIALLY DUE TO AN EASTERLY WAVE MERGING
WITH THE CIRCULATION AND SOME DRY AIR INTRUDING INTO THE SYSTEM.NHC
GUIDANCE FAVORS THE LOW TRACKING NORTHWESTERLY...WITH GOOD
POTENTIAL FOR TROPICAL CYCLONE FORMATION. EVEN IF THE LOW DOES NOT
DEVELOP SIGNIFICANTLY...THERE IS STRONG GRADIENT NE OF THE LOW
LEVEL CIRCULATION...ROUGHLY FROM 15N-21N BETWEEN 52W-60W...WHERE
E 20-25 KT WINDS ARE CURRENTLY SUPPORTED AS NOTED IN THE 1308
ASCAT PASS FROM THIS MORNING. EXPECT THE GRADIENT TO GRADUALLY
TIGHTEN TONIGHT INTO FRI SUPPORTING AN INCREASE TO AT LEAST 20-30
KT BY LATE FRI NIGHT. RECON WILL INVESTIGATE THE AREA TODAY AND
GET A BETTER HANDLE OF THE AFFECTED AREA. THERE IS SOME
POSSIBILITY OF A MINIMUM GALE WARNING BEING POSTED OVER THE N...OR
NE...SEMICIRCLE EVEN IF TROPICAL CYCLONE FORMATION DOES NOT OCCUR.

FOR THIS FORECAST WILL MAITAIN CLOSE CONTINUITY WITH PREVIOUS FORECAST
REGARDING FORECAST TRACK OF THE TROPICAL LOW. THE LOW WILL REACH
TO NEAR 15N61W BY EARLY THIS EVENING...NEAR 16N66W EARLY ON
FRI...THEN TO VICINITY NE HISPANIOLA LATE FRI NIGHT...TO NEAR
THE WINDWARD PASSAGE AT SUNSET SAT...WITH THE LOW THEN MOVING NW
THROUGH THE BAHAMA CHAIN THROUGH MON NIGHT. EXACT TRACK AND
INTERACTION WITH THE LARGER ISLANDS WILL OF COURSE PLAY A MAJOR
PART IN THE ORGANIZATION OR WEAKENING OF THIS TROPICAL LOW...AND
MARINERS SHOULD EXPECT FREQUENT ADJUSTMENTS TO THE NDFD
GRIDS...TEXT AND MARINE GRAPHICS OVER THE NEXT WEEK. IN ANY EVENT
EXPECT AT LEAST FRESH TO STRONG WINDS WITHIN 540 NM N AND NE OF
THESE ESTIMATED POSITIONS.

...SW N ATLANTIC INCLUDING THE BAHAMAS...

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL
WHICH WAS MOSTLY GFS. NWPS USED FOR WAVE PARAMETERS. LOW-MED
CONFIDENCE DUE TO TROPICAL LOW.

PLEASE ALSO REFER TO CARIBBEAN AND TROPICAL ATLC SECTION FOR
DETAILS ON THE TROPICAL LOW. SIMILARLY TO THE GULF OF MEXICO...
A RIDGE NEAR 27N IS THE DOMINATE WEATHER FEATURE PRESENTLY
CONTROLING THE WIN D REGIME THROUGHOUT. THE RIDGE IS FORECAST
BY THE MODELS TO GRADUALLY SHIFT N TO NEAR 30N ON SUN...AND
RETREAT EASTWARD MON AND TUE AS STRONGER RIDGING BUILDS SSW
ALONG THE U.S. SE COAST.  A TROPICAL LOW...POSSIBLY A TROPICAL
CYCLONE...IS EXPECTED TO MOVE NW ACROSS THE CARIBBEAN AND INTO THE
ATLC NEAR HISPANIOLA ON SAT...THEN CONTINUE NW ACROSS OR VERY NEAR
THE BAHAMA ISLANDS THROUGH MON BEFORE TURNING NE WHILE INCREASING
ITS FORWARD SPEED. SW 10-15 KT WINDS WILL CONTINUE N OF THE RIDGE
THROUGH THE REST OF THIS AFTERNOON AND TONIGHT BEFORE DIMINISHING
TO 5-10 KT ON FRI. EASTERLY TRADES FROM THE RIDGE AXIS S TO ALONG
25N ARE EXPECTED TO CONTINUE INITIALLY AT 5-10 KT. TO THE S OF 25N
MODERATE 10-15 KT TRADES ARE EXPECTED W OF 65W...EXCEPT FOR 15-20
KT CONDITIONS ALONG THE N COAST OF HISPANIOLA. EXPECT EASTERLY
20-25 KT WINDS ACROSS THE WATERS S OF 23N E OF 65W THROUGH TONIGHT
...INCREASING TO 20-30 KT LATE FRI. MUCH UNCERTAINTY...BUT
EXPECT AT A MINIMUM A LARGE AREA OF ENHANCED 20-25 KT WINDS TO
SHIFT W ACROSS THE WATERS S OF 24N E OF THE BAHAMAS TODAY THROUGH
FRI...THEN MOVE THROUGH THE SOUTHERN BAHAMAS ON SAT...THE CENTRAL
BAHAMAS ON SUN...AND THE NORTHERN BAHAMAS ON SUN WITH POSSIBLE
TROPICAL CYCLONE FORMATION THROUGHOUT THE ENTIRE PERIOD. GUIDANCE
FROM THE NHC/WPC MEDIUM RANGE COORDINATION WILL BE USED FOR
THE FORECAST OF THE LOW...HOWEVER CAN ANTICIPATE MORE CHANGES ARE
VERY POSSIBLE TO THE NDFD GRIDS...TEXT AND MARINE GRAPHICS OVER
THE NEXT FEW DAYS WITH RESPECT TO THE AFOREMENTIONED TROPICAL LOW.

$$

.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 AGUIRRE. NATIONAL HURRICANE CENTER.



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