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AGXX40 KNHC 220806
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
405 AM EDT MON SEP 22 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 FORECAST. LATEST MWW3 USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE THROUGH TUE NIGHT. HIGH CONFIDENCE THEREAFTER.

LATEST SURFACE ANALYSIS HAS A STATIONARY FRONT FROM JUST N OF TAMPA BAY SW TO A WEAK 1013 MB LOW AT 27N89W AS CAPTURED ON A WIND SAT PASS FROM LAST NIGHT. WEAK HIGH PRES IS PRESENT ELSEWHERE. LATEST SATELLITE-DERIVED WINDS AND BUOY DATA SHOW MODERATE TO FRESH E WINDS N OF 26N...AND GENTLE E WINDS S OF 26N. THE OBSERVATIONS SHOW SEAS IN THE RANGES OF 1-2 FT E OF 91W...AND 2-4 FT W OF 91W EXCEPT FOR A POCKET OF HIGHER SEAS OF 4-6 FT E OF CENTRAL TEXAS FROM 26N TO 28N W OF 94W. NWPS WAVE PARAMETERS ARE RUNNING 2 FT UNDER CURRENT AND LATEST REPORTED VALUES FOR THE WESTERN GULF. OBSERVED VALUES ARE CLOSER TO THE MWW3 GUIDANCE.

SATELLITE WATER VAPOR SHOWS AMPLE DEEP LAYER MOISTURE CONFINED TO OVER THE EASTERN PORTION OF THE GULF TO THE SE OF AN UPPER TROUGH THAT STRETCHES FROM THE SE U.S. SW TO 25N89W AND TO EASTERN BAY OF CAMPECHE. THE UPPER TROUGH IS ENHANCING INSTABILITY ALONG...AND TO THE S OF THE STATIONARY FRONT AND WEAK 1013 MB WHERE SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED. ISOLATED SHOWERS AND TSTMS ARE WITHIN 60 NM OF THE LOW.

AN AUTUMNAL TYPE WEATHER PATTERN WILL BEGIN TO SET-UP GOING INTO THE MIDDLE PART OF THE WEAK AS A COLD FRONT PRESENTLY N OF THE AREA MOVING THROUGH THE SE U.S. PUSHES S TO OVER THE N CENTRAL AND NE GULF TONIGHT AND EARLY ON TUE WHILE THE CURRENT STATIONARY FRONT SLOWLY LOSES ITS IDENTITY. A LARGE DOME OF RELATIVELY HIGH PRESS WITH ASSOCIATED DRIER AIR WILL SURGE SOUTHWARD ACROSS THE FRONT TO OVER THE FAR NORTHERN GULF WATERS THROUGH THU BEFORE WEAKENING SOME ON FRI AS SUGGESTED BY THE MODELS. THE COLD FRONT WILL TRANSITION TO A STATIONARY FRONT DURING THE PERIOD. A TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND FRONTAL BOUNDARY WILL INITIATE AN INCREASE OF THE ELY WINDS TO THE FRESH TO STRONG RANGE OVER THE FAR N CENTRAL GULF WATERS WITH MOST OF THESE WINDS MAINLY OVER THE COASTAL WATERS BEGINNING TUE NIGHT...AND CONTINUING THROUGH MUCH OF THU BEFORE DIMINISHING TO MODERATE INTENSITY LATE ON THU AND INTO FRI. E WINDS OVER THE FAR NE GULF ARE EXPECTED TO INCREASE TO MAINLY THE MODERATE RANGE BEGINNING TONIGHT...AND LAST THROUGH FRI. WAVEWATCH GUIDANCE FORECASTS SEAS THERE TO BUILD TO AROUND 6 OR 7 FT UNDER THE INCREASING ELY WINDS.

AN INVERTED TROUGH THAT SETS-UP OFF THE FLORIDA COAST BY TUE NIGHT WILL MOVE WESTWARD ACROSS FLORIDA AND INTO THE EASTERN GULF THU THROUGH FRI. LOW-LEVEL MOISTURE RELATED TO THIS TROUGH IN COMBINATION WITH THAT FROM THE TROUGH ALOFT SHOULD HELP TRIGGER ADDITIONAL SHOWER AND TSTM ACTIVITY OVER THE EASTERN PORTION. SOME MOISTURE FROM THE EASTER CARIBBEAN TROPICAL COULD GET CAUGHT UP IN SW FLOW AHEAD OF THE UPPER TROUGH AND MOVE INTO THE E GULF AS WELL...BUT IT APPEARS THE BULK OF THIS MOISTURE SHOULD STAY JUST SE OF THE AREA.


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

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. MWW3/NWPS BLEND WITH MORE WEIGHT TOWARDS THE MWW3 FOR WAVE PARAMETERS. HIGH CONFIDENCE.

RELATIVELY BENIGN CONDITIONS CONTINUE OVER THE CARIBBEAN AND TROPICAL N ATLC WATERS PER LATEST SHIP AND BUOY DATA ALONG WITH PARTIAL ASCAT DATA FROM LAST NIGHT. BASED ON LATEST MODEL DATA THESE CONDITIONS ARE EXPECTED TO CHANGE VERY LITTLE THROUGH THE END OF WEEK WITH ELY WINDS REMAINING IN THE GENTLE TO MODERATE CATEGORY...AND SEAS SEAS AT RATHER LOW LEVELS THROUGH THE PERIOD.

NWPS VALUES ARE ABOUT 2 FT TOO LOW OVER THE WESTERN CARIBBEAN. WILL WEIGH WAVEHEIGHTS CLOSER TO THE MWW3 FOR GUIDANCE.

THE SUBTROPICAL RIDGE N OF THE AREA IS WEAK MAINTAINING A LIGHT PRES GRADIENT ACROSS THE CARIBBEAN. THE 06 UTC SURFACE ANALYSIS SHOWS A TROPICAL WAVE OVER THE EASTERN CARIBBEAN NEAR 63W MOVING W ABOUT 15-20 KT. ANOTHER WAVE HAS MOVED INTO THE WESTERN CARIBBEAN JUST E OF THE COAST OF HONDURAS AND NICARAGUA MOVING W AT 15 KT. A LARGE AREA OF SCATTERED SHOWERS AND TSTMS IS OBSERVED TO THE E OF THE WAVE ALONG 63W COVERING MUCH OF THE TROPICAL N ATLC WATERS FROM 13N TO 20N BETWEEN 55W AND 62W...MAINLY ENHANCED BY AN UPPER LOW NE OF THE AREA NEAR 25N51W THAT EXTENDS A TROUGH SW TO JUST NE OF THE TROPICAL N ATLC WATERS.

THE TROPICAL WAVE ALONG 63W WILL MOVE ACROSS THE REST OF THE EASTERN CARIBBEAN THROUGH TONIGHT...THEN ACROSS THE CENTRAL CARIBBEAN TUE THROUGH MUCH OF WED...AND THE WESTERN CARIBBEAN LATE WED THROUGH THU NIGHT. THE WAVE OVER THE WESTERN CARIBBEAN SEAS WILL MOVE INLAND TONIGHT. THESE WAVES ARE EXPECTED TO HAVE LITTLE IMPACTS ON WINDS AND SEAS. GUSTY WINDS ARE POSSIBLE WITH ASSOCIATED SHOWER AND TSTM ACTIVITY.




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

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL. MWW3/NWPS BLEND USED FOR WAVE PARAMETERS. MEDIUM-HIGH CONFIDENCE.

THE 06 UTC SURFACE ANALYSIS HAS A COLD FRONT EXTENDING FROM NEAR 31N71W TO 28N76W WHERE IT BECOMES STATIONARY TO 29N79W AND SW TO INLAND FLORIDA NEAR CAPE CANAVERAL. RELATIVELY WEAK HIGH PRES IS PRESENT ELSEWHERE. AN ASCAT PASS FROM 0120 UTC LAST NIGHT SHOWED MODERATE S-SW WINDS OVER THE FAR NE PORTION OF ZONE 113 AND GENTLE E-SE WINDS ELSWHERE. THE BUOY AND SHIP OBSERVATIONS ALONG WITH A ALTIMETER PASSES SHOW SEAS IN THE 4-5 FT RANGE E OF THE BAHAMAS AND 1-2 FT SEAS W OF THE BAHAMAS...AND ALSO N OF 27N W OF 80W. HIGHER SEAS OF 6-7 FT ARE UNDER THE MODERATE S-SW WINDS.

UPCOMING CHANGES PERTAIN TO A COLD FRONT FORECAST TO MOVE OFF THE U.S SE COAST AND INTO THE FAR NW WATERS LATE TONIGHT INTO EARLY TUE. WITH THE UPPER SUPPORT HANGING BACK TO THE W OF THE AREA OVER THE GULF OF MEXICO...THE FRONT WILL SAG A LITTLE S BEFORE BECOMING STATIONARY LATER IN TUE. MODELS IN PRETTY GOOD CONSENSUS IN DEPICTING STRONG HIGH THAT BUILDS S JUST TO THE NW OF THE AREA TUE THROUGH THU NIGHT BEFORE WEAKENING SOME ON FRI. THIS WILL PROVIDE A WEDGE TYPE PATTERN OF HIGH PRES RIDGING OVER NE FLORIDA WITH AN INVERTED TROUGH SETTING UP ALONG THE N AND CENTRAL FLORIDA COAST. THE PRES GRADIENT BETWEEN THE RIDGE AND TROUGH WILL ALLOW FOR ELY WINDS TO INCREASE OVER THE FAR NW WATERS LATE TUE THROUGH WED AFTERNOON. THE INVERTED TROUGH WILL MOVE W OF THE AREA AND INTO THE EASTERN GULF THU ALLOWING FOR THE GRADIENT OVER THE FAR NW WATERS TO SLACKEN.

$$


.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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