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AGXX40 KNHC 200759
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
359 AM EDT SAT SEP 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 FORECAST. MWW3 USED FOR WAVE PARAMETERS. HIGH CONFIDENCE.

A SURFACE TROUGH EXTENDS FROM THE NW BAHAMAS WSW ACROSS S FLORIDA AND ACROSS THE GULF FROM NEAR FORT MYERS TO 27N87W TO 25N95W. LATEST SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED S OF THE TROUGH MOVING EASTWARD. A RIDGE EXTENDS SW ACROSS THE EASTERN PORTION OF THE U.S. TO EASTERN ALABAMA. LATEST SATELLITE-DERIVED WINDS...ALTIMETER DATA ALONG WITH SHIP AND BUOY DATA DEPICT GENTLE TO MODERATE WINDS WITH SEAS IN THE 1-3 FT RANGE OVER JUST ABOUT THE ENTIRE AREA...EXCEPT FOR A SMALL POCKET OF 3-4 FT SEAS JUST E OF NE MEXICO AND FAR SOUTHERN TEXAS...AND IN THE EASTERN BAY OF CAMPECHE. HIGHER SEAS OF 5-8 FT ARE CONFINED TO THE FAR NE GULF N OF 29N BETWEEN 85W-87W. LOW PRES IS FORMING E OF THE GULF ALONG THE TROUGH E OF CENTRAL FLORIDA. THE LOW IS FORECAST TO LIFT NE INTO EARLY SUN. WITH THIS TAKING PLACE THE TROUGH WILL LIFT SLIGHTLY NORTHWARD TO EXTEND FROM CENTRAL FLORIDA TO THE CENTRAL GULF BY LATE ON SUN. THE TROUGH WILL SLOWLY DISSIPATE EARLY NEXT WEEK. RELATIVELY BENIGN CONDITIONS WILL PREVAIL OVER MUCH OF THE GULF WATERS THROUGH THE FORECAST PERIOD. THE TIGHT PRES GRADIENT OVER THE N CENTRAL AND NE GULF BETWEEN THE RIDGE AND THE AFOREMENTIONED TROUGH IS CURRENTLY ALLOWING FOR FRESH ELY WINDS TO EXIST N OF 27N E OF 91W. THESE WINDS WILL DIMINISH TO A GENTLE BREEZE THIS AFTERNOON AND TONIGHT...AND SEAS THERE WILL SUBSIDE AS THE GRADIENT SLACKENS WITH THE LOW E OF THE GULF LIFTING NE...AND THE RIDGE JUST N OF THE AREA BREAKS DOWN. WEAK TROUGHING WILL LINGER OVER THE SW GULF THROUGH PERIOD WITH VERY LITTLE IMPACT ON WINDS AND SEAS.


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

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. MWW3 USED FOR WAVE PARAMETERS. HIGH CONFIDENCE.

A TROPICAL WAVE IS OVER THE CENTRAL PART OF THE CARIBBEAN NEAR 72W
...WITH AN ESTIMATED WESTWARD MOTION OF 10-15 KT. LATEST SATELLITE- DERIVED WINDS...ALTIMETER DATA ALONG WITH SHIP AND BUOY DATA DEPICT GENTLE TO MODERATE TRADES OVER THE CARIBBEAN AND TROPICAL N ATLC WATERS. SEAS ARE IN THE 2-4 FT RANGE OVER THE CARIBBEAN WATERS...EXCEPT IN THE LEE OF CUBA WHERE SEAS ARE IN THE 1-2 FT RANGE. SEAS ARE IN THE 4-5 FT IN THE TROPICAL N ALTC DUE TO A NE TO E SWELL THERE. A WEAK PRES GRADIENT WILL PREVAIL OVER THE FORECAST WATERS THROUGH THE FORECAST PERIOD WITH LITTLE CHANGE IN WINDS...AND SEAS REMAINING AT RELATIVELY LOW RANGES. THE TROPICAL WAVE WILL MOVE ACROSS THE REMAINDER OF THE CENTRAL CARIBBEANTHROUGH TONIGHT...AND ACROSS THE WESTERN PORTION OF THE SEA THROUGH EARLY TUE WITH LITTLE IMPACT ON WINDS AND SEAS AS IT REMAINS RATHER WEAK AT THE SURFACE. ANOTHER TROPICAL WAVE CURRENTLY E OF THE TROPICAL N ATLC ZONES NEAR 51W PER LATEST ASCAT PASS FROM JUST AFTER 00 UTC LAST NIGHT. THIS POSITION COINCIDES VERY WELL WITH THAT OF THE GLOBAL MODELS. THE WAVE WILL ENTER THE EASTERN PORTION OF THE TROPICAL N ATLC EARLY THIS EVENING...AND MOVE ACROSS THE REMAINDER OF THOSE WATERS TONIGHT BEFORE PASSING THROUGH THE LESSER ANTILLES AND INTO EASTERN CARIBBEAN SEA EARLY ON SUN. MODELS SUGGEST THAT THE NE TO SE WIND SHIFT WILL ACCOMPANY THE WAVE AS IT MOVES THROUGH THE EASTERN CARIBBEAN SEA THROUGH LATE MON...THEN DAMPEN OUT AS IT MOVES ACROSS THE CENTRAL CARIBBEAN TUE THROUGH WED NIGHT. EXCEPT FOR TSTM ACTIVITY THAT CAN GENERATE GUSTY WINDS...THIS WAVE WILL ALSO HAVE LITTLE IMPACT ON WINDS AND SEAS.


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

MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. MWW3 USED FOR WAVE PARAMETERS. HIGH CONFIDENCE...EXCEPT FOR MEDIUM CONFIDENCE WITH EXPECTED LOW PRES OFF THE FLORIDA COAST.

THE 06 UTC SURFACE ANALYSIS HAS A PERSISTENT STATIONARY FRONTAL BOUNDARY THAT STRETCHES FROM NEAR BERMUDA WSW TO 29N75W TO INLAND FLORIDA NEAR CAPE CANAVERAL. TO ITS S...A TROUGH EXTENDS FROM NEAR 27N73W W TO WEST PALM BEACH FLORIDA...AND CONTINUES W TO NEAR FORT MYERS AND ACROSS MUCH OF THE GULF OF MEXICO. A WEAK RIDGE EXTENDS FROM 30N65W SW TO STRAITS OF FLORIDA.

LATEST SATELLITE-DERIVED WINDS ALTIMETER DATA ALONG WITH SHIP AND BUOY DATA DEPICT LIGHT TO GENTLE WINDS ACROSS MUCH OF THE BASIN... WITH THE EXCEPTION OF FRESH NE WINDS OVER THE NW PORTION N OF ABOUT 29N AND W OF 75W WHERE A TIGHT PRES GRADIENT THERE BETWEEN HIGH PRES STRETCHING NE TO SW OVER THE EASTERN U.S. AND THE STATIONARY FRONT IS SUPPORTING THESE WINDS. SEAS THERE ARE IN THE 5-8 FT RANGE. SEAS ELSEWHERE ARE IN THE 3-4 FT...EXCEPT FOR LOWER SEAS OF 1-3 FT W OF THE BAHAMAS.

A RATHER VIGOROUS UPPER TROUGH OVER THE SE U.S. AND N CENTRAL/NE GULF OF MEXICO WILL SWING EASTWARD ACROSS THE NW PORTION OF THE FORECAST WATERS THIS AFTERNOON...AND HELP SPIN UP LOW PRES OF THE FLORIDA COAST NEAR 29N79W AS THE SURFACE TROUGH LIFTS NW AND APPEARS TO MERGE WITH THE STATIONARY FRONT. MODELS ARE IN BETTER AGREEMENT WITH TIMING OF LOW ONCE IT FORMS TO TRACK NEWD AND ACCELERATE REACHING THE WATERS JUST N OF THE AREA NEAR 32N78W TONIGHT. WINDS WILL STRENGTHEN IN THE SE QUADRANT OF THE LOW WITH SEAS IN THAT AREA BUILDING TO AROUND 8 OR 9 FT. ONCE THE LOW LIFTS N OF THE AREA...THE WINDS IN THE NW PORTION WILL DIMINISH TO 10-15 KT AND TO 5-10 KT SUN NIGHT INTO MON WITH SEAS SUBSIDING TO 3-4 FT. HOWEVER...FRESH SLY WINDS OVER THE FAR NORTHERN WATERS... MAINLY IN ZONE 113...WILL LINGER INTO AT LEAST THE EARLY PART OF SUN AFTERNOON AS THE TIGHT PRES GRADIENT BETWEEN STRENGTHENING ATLC HIGH PRES AND A TRAILING TROUGH FROM LOW SLOWLY SLACKENS. BY LATE SUN AFTERNOON OR EARLY EVENING...THE WINDS THERE SHOULD HAVE DIMINISH TO 10-15 KT AND SEAS TO 4-6 FT. THE TROUGH WILL LINGER OVER THE NW WATERS THROUGH EARLY NEXT WEEK BEFORE DISSIPATING. STRENGTHENING HIGH PRES WILL SURGE SOUTHWARD OVER THE SE U.S. TUE NIGHT THROUGH WED NIGHT WITH INCREASING NE WINDS OVER THE NW WATERS EXPECTED AS AN INVERTED TROUGH TO ITS S SETS UP ALONG THE N AND CENTRAL FLORIDA COASTS. OTHERWISE...ASIDE FROM WIND/SEA CONDITIONS ASSOCIATED WITH THE EXPECTED LOW PRES/TROUGH CONDITIONS ELSEWHERE WILL CHANGE VERY LITTLE THROUGH THE FORECAST PERIOD.

$$


.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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