Marine Interpretation Message
Issued by NWS

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000
AGXX40 KNHC 201826
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
226 PM EDT WED AUG 20 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 USED FOR WAVE PARAMETERS. HIGH CONFIDENCE.

THE NORTHERN EXTENSION OF A TROPICAL WAVE OVER THE WESTERN BAY OF
CAMPECHE WILL MOVE INLAND MEXICO THIS AFTERNOON. A RIDGE EXTENDS
FROM FL BAY TO THE NW GULF COAST WITH A HIGH PRES CENTER ALONG THE
RIDGE NEAR 27N87W. THE HIGH WILL GRADUALLY SHIFT NW ALONG THE
RIDGE TO THE N-CENTRAL GULF ON THU AND THU NIGHT...THEN SHIFTING
NW OVER 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 INTO EARLY NEXT WEEK.

VARIABLE 5-10 KT WINDS EXPECTED OVER THE NE GULF WATERS TILL FRI
...THEN LIGHT AND VARIABLE CONDITIONS DEVELOPING AGAIN ON FRI
NIGHT AND SAT. EXPECT SE-S 10-15 KT RETURN FLOW ACROSS THE
W-CENTRAL AND NW WATERS AROUND THE W PERIPHERY OF THE RIDGE
THROUGH THU NIGHT...EXCEPT INCREASING BRIEFLY TO 15-20 KT DURING
THE LATE NIGHT HOURS. THE GRADIENT WILL GRADUALLY RELAX FRI
THROUGH MON.

S OF 23N...EXPECT AN EVENING ENHANCEMENT OF 20-25 KT NE WINDS
ALONG THE W COAST OF THE YUCATAN PENINSULA THIS EVENING AND
AGAIN ON THU EVENING WITH THE MOST SIGNIFICANT EVENT TONIGHT.
THESE 20-25 KT CONDITIONS WILL SPREAD W ALONG 22N GRADUALLY
BECOMING E TO SE LATE TONIGHT...AND DIMINISH TO SE AT 20 KT NEAR
22N94W BY SUNRISE THU. THE THU EVENING EVENT WILL DAMPEN QUICKLY
TO E AT 10-15 KT BY SUNRISE FRI. AS STATED PREVIOUSLY...BEGINNING
FRI EVENING THE LOCALLY ENHANCED EVENING WINDS WILL SET 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.

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

MODEL PREFERENCE:  LATEST GFS BLENDED WITH PREVIOUS OFFICIAL
WHICH CONSISTED OF A GFS/ECMWF BLEND FOR DAY 4 AND 5. NWPS USED
FOR WAVE PARAMETERS. LOW-MED CONFIDENCE.

FRESH EASTERLY TRADES WILL CONTINUE ACROSS THE CENTRAL CARIBBEAN
THROUGH EARLY FRI WITH THE MAXIMUM AFFECTED AREA OCCURRING
DURING THE LATE NIGHT HOURS. TROPICAL LOW PRES CONTINUES NEAR
11N53W BUT REMAINS DISORGANIZED FOR THE TIME BEING. LATEST
NHC/WPC GUIDANCE FAVORS THE LOW TRACKING NORTHWESTERLY...WITH THE
POTENTIAL FOR TROPICAL CYCLONE FORMATION. THE GRIDS HAVE BEEN
ADJUSTED IN THE MEDIUM RANGE PERIODS TO ACCOUNT FOR SHIFT IN THE
TRACK OF THE LOW OR POSSIBLE TROPICAL CYCLONE SLIGHTLY TO THE N
FROM THE ONES SHOWN IN PREVIOUS GRIDS. THIS WAS BASED ON THE
NHC/WPC MIDDAY COORDINATION. PRESENTLY...A SURFACE LOW CENTER IS
EXPECTED TO MOVE INTO THE TROPICAL ATLC WATERS NEAR 13N55W LATE
TONIGHT WITH 20-25 KT WINDS WITHIN ABOUT 240 NM OVER THE NE
SEMICIRCLE. THE AREA OF ENHANCED WINDS WILL INCREASE TO 20-30
KT...AND SHIFT TO OVER THE N SEMICIRCLE AS THE LOW CONTINUES TO
NEAR 14N59W ON THU EVENING...TO NEAR NEAR 15N64W EARLY ON
FRI...NEAR 16N68W ON FRI EVENING...THEN BEGIN TO ACCELERATE IN
FORWARD SPEED AS TRACKS MORE TO THE NW REACHING A PSN TO JUST S OF
CENTRAL HISPANIOLA EARLY ON SAT. THE LOW WILL OR POSSIBLE TROPICAL
CYCLONE IS THEN FORECAST TO APPROACH THE EASTERN PART OF CUBA
EARLY SUN...AND CONTINUE NW THROUGH THE STRAITS OF FLORIDA
THEREAFTER. INTERACTION WITH THE LARGER ISLANDS WILL OF COURSE
PLAY A MAJOR PART IN THE ORGANIZATION OF THIS TROPICAL LOW...AND
MARINERS SHOULD EXPECT FREQUENT ADJUSTMENTS TO THE NDFD
GRIDS...TEXT AND GRAPHICS OVER THE NEXT WEEK.

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

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL
WHICH CONSISTED OF A GFS/ECMWF BLEND FOR DAY 4 AND 5. NWPS/MWW3 USED
FOR WAVE PARAMETERS. LOW-MED CONFIDENCE DUE TO TROPICAL LOW.

A RIDGE WILL PERSIST NEAR 27N THROUGH THU NIGHT...THEN SHIFT N TO
28N FRI THROUGH MON. EXPECTING SW 10-15 KT CONDITIONS N OF THE
RIDGE...EXCEPT DIMINISHING SOME W OF 73W OVER THE WEEKEND...AND
INTO MON.

EASTERLY TRADES FROM THE RIDGE AXIS S TO ALONG 22N ARE EXPECTED
TO CONTINUE AT 5-10 KT. TO THE S OF 22N MODERATE 10-15 KT TRADES
ARE EXPECTED...EXCEPT FOR 15-20 KT CONDITIONS ALONG THE N COAST
OF HISPANIOLA TILL LATE FRI WHEN THE EFFECTS OF A TROPICAL LOW
SHIFTING W ACROSS THE NORTHER CARIBBEAN WILL BEGIN TO SPREAD
ACROSS THE WATERS S OF 21N. MUCH UNCERTAINTY FOR THE 3-6 DAY
FORECAST AT THIS TIME AS MODEL GUIDANCE CONTINUES TO VARY.

$$

.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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