Marine Interpretation Message
Issued by NWS

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AGXX40 KNHC 260857 CCA
MIMATS

MARINE WEATHER DISCUSSION...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL
350 AM EDT TUE JUL 26 2016

CORRECTED SW N ATLC SECTION FOR HIGH PRES LOCATION

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: FOR WINDS USED BLEND OF 00Z GFS WITH PREVIOUS
OFFICIAL. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 AND TAFB NWPS
OUTPUT WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE.

A MID-LEVEL LOW NEAR 27N89W ALONG WITH AMPLE DEEP MOISTURE
PRESENT ACROSS THE AREA IS PROVIDING INSTABILITY LEADING TO THE
EXISTENCE OF SCATTERED SHOWERS AND ISOLATED TSTMS OVER MUCH OF
THE CENTRAL AND ERN GULF PORTIONS. IN ADDITION...A SURFACE
TROUGH EXTENDS FROM NEAR 28N87W NW TO A 1012 MB LOW OVER SE
LOUISIANA. WEAK HIGH PRES RIDGING IS PRESENT OVER THE FAR
ERN GULF ALONG 27N E OF 87W.

LATEST BUOY OBSERVATIONS AND RECENT ASCAT DATA INDICATE THAT THE
PRES GRADIENT OVER THE AREA IS SUPPORTING GENERALLY GENTLE TO
MODERATE WINDS THROUGHOUT WITH WINDS NOTED IN A CYCLONIC FASHION
OVER THE N CENTRAL WATERS BETWEEN 86W-91W AS WAS ALSO NOTED IN
THE 0234Z ASCAT PASS. THE BUOY OBSERVATIONS ALONG WITH RECENT
ALTIMETER PASSES SHOW RELATIVELY LOW SEAS OF 1-2 FT RANGE...
EXCEPT FOR HIGHER SEAS IN THE 3-5 FT RANGE S OF 25N BETWEEN
89W-97W AND FROM 25N-29N BETWEEN 84W-91W.

THE MID LEVEL LOW IS FORECAST TO WEAKEN AS IT CONTINUES WESTWARD
TO NW GULF THIS AFTERNOON. GLOBAL MODELS ARE IN GOOD AGREEMENT
THAT THE ATLC RIDGE WILL EXTEND WESTWARD ACROSS THE REMAINDER OF
THE GULF TONIGHT THROUGH SAT NIGHT. OTHERWISE...THE TYPICAL
CLIMO THERMAL TROUGH IN THE YUCATAN PENINSULA WILL PUSH OFFSHORE
INTO THE SW GULF EACH NIGHT THROUGH THE PERIOD ATTENDANT BY A
BRIEF PERIOD OF FRESH N TO NE WINDS AND A SLIGHT INCREASE OF
SEAS.

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

MODEL PREFERENCE: FOR WINDS USED BLEND OF 00Z GFS WITH PREVIOUS
OFFICIAL. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 AND TAFB
NWPS OUTPUT WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE.

THE PRES GRADIENT BETWEEN HIGH PRES ACROSS THE CNTRL ATLC AND
LOWER PRES IN THE NRN PORTIONS OF S AMERICA...AND ALSO IN THE SW
CARIBBEAN WHERE THE ERN PORTION OF THE E PACIFIC MONSOON TROUGH
IS LOCATED IS MAINTAINING FRESH TO STRONG ELY WINDS ACROSS THE S
CNTRL CARIBBEAN. THE GRADIENT PRODUCING THESE WINDS WILL TIGHTEN
FURTHER TONIGHT...AND CONTINUE TO DO SO THROUGH THU. THIS WILL
ALLOW FOR THESE WINDS TO EXPAND IN COVERAGE N TO JUST S OF
HISPANIOLA...AND EWD TO NEAR 69W BY THU WITH RESULTANT SEAS
BUILDING TO 10 FT. AS THE GRADIENT RELAXES ON FRI...THE WINDS
WILL RESPOND BY DECREASING IN BOTH COVERAGE AND IN SPEEDS.
HOWEVER...THE SEAS TO 10 FT WILL BE SLOW IN SUBSIDING IN THE
CNTRL CARIBBEAN ON FRI.

A TROPICAL WAVE MOVING RAPIDLY WWD UNDER THE ATLC RIDGE CROSSED
THE LESSER ANTILLES ON MON EVENING...AND IS ANALYZED OVER THE
FAR ERN CARIBBEAN AS OF 06Z. SCATTERED SHOWERS AND TSTMS ARE
OCCURRING ALONG AND NEAR THE NRN PORTION OF THE WAVE OVER THE
VIRGIN ISLANDS. THE WAVE WILL MOVE ACROSS THE REMAINDER OF THE
ERN CARIBBEAN THROUGH THIS EVENING...THEN ACROSS THE CNTRL
CARIBBEAN WED AND WED NIGHT...AND THE WRN CARIBBEAN THU AND THU
NIGHT BEFORE MOVING INLAND CENTRAL AMERICA. ANOTHER TROPICAL
WAVE WILL REACH THE TROPICAL N ATLC LATE FRI NIGHT...AND THE ERN
CARIBBEAN SAT AND SAT NIGHT. MODELS SUGGEST THAT THIS WAVE WILL
BE ACCOMPANIED BY A WELL PRONOUNCED NE TO SE WIND SHIFT ALONG A
WITH A POCKET OF TIGHT PRES GRADIENT AND BUILDING SEAS ALONG ITS
NRN SEGMENT.

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

MODEL PREFERENCE: FOR WINDS USED BLEND OF 00Z GFS WITH PREVIOUS
OFFICIAL. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 AND TAFB NWPS
OUTPUT WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE...EXCEPT
AVERAGE CONFIDENCE SE PORTION SAT AND SAT NIGHT.

A RIDGE AXIS EXTENDING FROM A 1020 MB HIGH NEAR 28N69W NW TO NE
FL IS THE MAIN FEATURE OVER THE BASIN. A WEAK SURFACE TO LOW-
LEVEL TROUGH IS OVER THE CNTRL BAHAMAS. ONLY ISOLATED SHOWERS
AND TSTMS ARE NOTED WITHIN 90 NM OF THE TROUGH AT THIS TIME.

THE 06Z ANALYSIS REVEALS A RATHER WEAK PRES GRADIENT THROUGHOUT
WITH LIGHT TO GENTLE E-SE WINDS ACROSS MUCH OF THE
BASIN...EXCEPT FOR THE NE PORTION WHERE WINDS ARE LIGHT AND
VARIABLE MAINLY W-NW IN DIRECTION AND FROM THE SE BAHAMAS TO THE
COAST OF HISPANIOLA WHERE E WINDS ARE IN THE MODERATE TO FRESH
RANGE. BOTH BUOY AND ALTIMETER DATA SHOW SEAS IN THE RANGE OF 3-
5 FT E OF THE BAHAMAS...EXCEPT FOR SEAS OF 2-3 FT N OF 25N AND
ALSO N OF THE BAHAMAS W OF 77W. SEAS IN THE LOWER RANGE OF 1-2
ARE SW OF THE BAHAMAS...AND 1-2 FT N OF 27N W OF 70W. A SMALL
POCKET OF SEAS IN THE 5-6 FT RANGE ARE NOTED BETWEEN THE SE
BAHAMAS AND HISPANIOLA.

THE RIDGE IS FORECAST TO CHANGE LITTLE THROUGH THU NIGHT...THEN
WILL BE REPLACED BY STRONGER CNTRL ATLC RIDGING THAT BUILDS
WESTWARD NEAR 29N FRI THROUGH SAT NIGHT. MODELS SUGGEST THAT
TIGHTENING OF THE PRES GRADIENT IS LIKELY TO OCCUR IN THE SE
PORTION OF THE BASIN BEGINNING LATE ON SAT AS THE NRN PORTION OF
A TROPICAL WAVE MOVES THROUGH THAT AREA. WINDS THERE WILL
RESPOND IN A NE TO SE FASHION WILL INCREASING IN SPEEDS WITH
RELATED SEAS POSSIBLY BUILDING TO AROUND 7 OR 8 FT. OTHERWISE...
THE FLOW PATTERN S OF THE RIDGE WILL BECOME E-SE WITH WINDS IN
THE GENTLE TO MODERATE RANGE...EXCEPT FOR THE STRONGER PULSING E
WINDS TO THE STRONG CATEGORY BETWEEN THE BAHAMAS AND HISPANIOLA.
WITH THESE WINDS SEAS ARE EXPECTED TO BUILD TO 7 FT...WITH
WAVEWATCH GUIDANCE AND NWPS OUTPUT SHOWING SEAS BUILDING TO 8 FT
WED NIGHT AND AGAIN ON SAT NIGHT.

$$

.WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE
COORDINATED THROUGH AWIPS II COLLABORATION 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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