000
AGXX40 KNHC 250800
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
400 AM EDT MON JUL 25 2016

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.

THE MID TO UPPER LEVEL LOW THAT WAS E OF FL THE PAST FEW DAYS IS
PRESENTLY OVER THE FAR SE GULF. THIS FEATURE IN COMBINATION WITH
AN INVERTED TROUGH OVER THE SW GULF ARE LEADING TO AMPLE
INSTABILITY RESULTING IN SCATTERED SHOWERS AND TSTMS OVER MUCH
OF ERN AND CNTRL WATERS. THIS ACTIVITY HAS AMOUNTED TO MORE THAN
EARLIER ANTICIPATED. THE NRN PORTION OF A TROPICAL WAVE AXIS
OVER THE EASTERN PACIFIC ALONG 95W EXTENDS N TO 20N IN THE BAY
OF CAMPECHE AREA. SCATTERED SHOWERS AND TSTMS WITH FREQUENT
LIGHTNING STRIKES ARE OBSERVED WITHIN 180 NM E OF THE AXIS. THE
WEAK ATLC RIDGE AXIS THAT WAS OVER THE NRN GULF THE PAST SEVERAL
DAYS HAS SHIFTED S TO NEAR 27N E OF 88W.

LATEST BUOY OBSERVATIONS AND RECENT ASCAT DATA INDICATE THAT THE
PRES GRADIENT OVER THE AREA IS SUPPORTING GENERALLY GENTLE ELY
WINDS...EXCEPT FOR THE FAR EASTERN PART OF BAY OF CAMPECHE ALONG
THE YUCATAN PENINSULA WHERE WINDS OF MODERATE INTENSITY FROM THE
NE-E IN DIRECTION ARE NOTED. THE BUOY OBSERVATIONS ALONG WITH
RECENT ALTIMETER PASSES SHOW RELATIVELY LOW SEAS OF 1-2 FT RANGE.

THE MID TO UPPER LEVEL LOW IS FORECAST TO WEAKEN AS IT CONTINUES
WESTWARD TO THE CENTRAL GULF OVER THE NEXT 24-36 HRS. THE ATLC
RIDGE WILL THEN SHIFT BACK N TO THE NRN PORTION OF THE GULF
THROUGH THE END OF THE WEAK...WITH THE ASSOCIATED GRADIENT
EXPECTED TO SUPPORT GENERALLY GENTLE TO MODERATE E-SE WINDS
THROUGHOUT. THE AFOREMENTIONED TROPICAL WAVE WILL MOVE W OF THE
GULF TONIGHT. 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 CENTRAL ATLC AND
LOWER PRES IN 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 A
SMALL PORTION OF THE FAR S CENTRAL CARIBBEAN AS WELL AS WITHIN
ABOUT 90 NM OF THE COAST OF COLOMBIA. THE GRADIENT PRODUCING
THESE WINDS WILL TIGHTEN BEGINNING ON TUE...AND CONTINUE TO
DO SO THROUGH MUCH OF FRI. THIS WILL ALLOW FOR THESE WINDS TO
EXPAND IN COVERAGE N TO JUST S OF HISPANIOLA...AND EASTWARD TO
NEAR 69W BY THU WITH RESULTANT SEAS BUILDING TO 10 FT. AS THE
GRADIENT THEN RELAXES SOME ON FRI...THE WINDS WILL RESPOND BY
DECREASING IN BOTH COVERAGE AND SPEEDS. HOWEVER...SEAS TO 10 FT
WILL BE SLOW IN SUBSIDING IN THE CENTRAL CARIBBEAN ON DAY 5
(FRI).

A TROPICAL WAVE OVER THE CENTRAL TROPICAL N ATLC WITH AXIS
ANALYZED ALONG 56W S OF 21N IS RACING W AT ABOUT 30 KT. THIS
WAVE WILL MOVE ACROSS THE LESSER ANTILLES AND EASTERN CARIBBEAN
TONIGHT INTO TUE...THEN OVER THE CENTRAL CARIBBEAN DURING THE
REMAINDER OF TUE AND THROUGH WED NIGHT...AND THE WESTERN
CARIBBEAN THU THROUGH EARLY FRI. THE WAVE WILL HELP ADD MOMENTUM
TO THE EXPECTED TIGHTENING PRES GRADIENT IN THE CENTRAL
CARIBBEAN.

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

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 RIDGE AXIS EXTENDING ALONG 27N/28N IS THE MAIN FEATURE OVER
THE BASIN. A WEAK SURFACE TO LOW-LEVEL TROUGH IS ANALYZED AS OF
06Z ALONG 69W S OF 22N. ONLY ISOLATED SHOWERS AND TSTMS ARE
NOTED WITHIN 120 NM W 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 MAINLY S-
SW IN DIRECTION. BOTH BUOY AND ALTIMETER DATA SHOW SEAS IN THE
RANGE OF 2-4 FT E OF THE BAHAMAS...0-1 FT SW OF THE
BAHAMAS...AND 1-2 FT N OF 27N W OF 70W. A SMALL POCKET OF SEAS
IN THE 4-5 FT RANGE ARE NOTED BETWEEN THE SE BAHAMAS AND
HISPANIOLA.

THE RIDGE IS FORECAST TO RE-ALIGN ITSELF ROUGHLY ALONG A PSN
FROM 29N69W NW TO NE FL BY TUE NIGHT WITH A 1020 MB HIGH
FORECAST TO BE NEAR 29N69W. THIS HIGH WILL WEAKEN SLIGHTLY IN
RESPONSE TO A FRONTAL TROUGH THAT BRUSHES THE FAR NE WATERS. 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.
SEAS ARE EXPECTED TO BUILD TO 8 FT BETWEEN THE SE BAHAMAS AND
HISPANIOLA TONIGHT BEFORE SUBSIDING TO 5-6 FT ON TUE.

$$

.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.