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AGXX40 KNHC 050735
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
335 AM EDT TUE MAY 5 2015

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.

MODEL PREFERENCE: 00 UTC GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. 00 UTC TAFB NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE.

A FAIRLY TIGHT PRESSURE GRADIENT IS IN PLACE AT THE SURFACE THIS MORNING BETWEEN STRONG HIGH PRES OFF THE CAROLINA COAST AND A BROAD SURFACE TROUGH FROM THE WESTERN TIP OF CUBA TO THE GULF OF HONDURAS. THE SURFACE TROUGH IS RELATED TO A BROAD UPPER TROUGH REACHING FROM THE NE GULF ACROSS WESTERN CUBA TO THE SW CARIBBEAN. BUOY OBSERVATIONS AND A 0345 UTC SCATTEROMETER PASS INDICATED 20 TO 25 KT WINDS ACROSS MUCH OF THE CENTRAL GULF WITH SEAS REACHING 8 FT OVER THE N CENTRAL GULF AND SE GULF. JET DYNAMICS ALOFT ARE SUPPORTING AREAS OF SHOWERS AND THUNDERSTORMS OVER THE SE GULF AND THE STRAITS OF FLORIDA.

THE TROUGH TO THE SOUTH WILL DAMPEN OUT AS THE HIGH PRES SHIFTS INTO THE TENNESSEE VALLEY...ALLOWING WINDS OVER THE EASTERN GULF TO DIMINISH. SEAS WILL SUBSIDE ACCORDINGLY THROUGH TODAY...WITH 3 TO 5 FT OVER THE WESTERN GULF AND 1 TO 3 FT OVER THE FAR EASTERN GULF THROUGH MID WEEK. SE RETURN FLOW WILL INCREASE HOWEVER OVER THE WESTERN GULF STARTING MID WEEK BETWEEN THE HIGH PRES OVER THE SOUTHEASTERN UNITED STATES AND LOW PRES MOVING INTO THE SOUTHERN PLAINS. WITH SEAS BUILDING 5 TO 7 FT. MEANWHILE WINDS WILL PULSE TO FRESH LEVELS ALONG AND JUST OFFSHORE OF THE NW YUCATAN PENINSULA DURING THE EVENING AND OVERNIGHT HOURS EACH NIGHT THROUGH THE WEEK.


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

MODEL PREFERENCE: 00 UTC GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. 00 UTC TAFB NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE.

SURFACE TROUGHING IS LOCATED IN THE NW CARIBBEAN WHICH CAN BE ATTRIBUTED BROAD AND ELONGATED UPPER TROUGHING REACHING FROM THE N CENTRAL GULF OF MEXICO THROUGH THE NW CARIBBEAN INTO THE SW CARIBBEAN THIS MORNING. DIVERGENCE ALOFT ASSOCIATED WITH THE LEFT FRONT EXIT REGION OF A JET STREAK ON THE WEST SIDE OF THE TROUGH AND THE RIGHT REAR ENTRANCE REGION ON ANOTHER JET STREAK ON THE EAST SIDE OF THE TROUGH IS ENHANCING A SCATTERED THUNDERSTORM ACTIVITY N OF 18N E OF 85W THROUGH CUBA.

A TIGHT PRES GRADIENT IS IN PLACE ACROSS THE S CENTRAL CARIBBEAN BETWEEN SUBTROPICAL RIDGING AND LOWER PRES ALONG NW COLOMBIA. THIS PATTERN IS SUPPORTING FRESH TO STRONG NE TO E WINDS ALONG THE NORTHERN COASTS OF COLOMBIA AND VENEZUELA. RESULTANT SEAS ARE 8 TO 11 FT ACCORDING TO THE LATEST TAFB NWPS LOCAL MODEL GUIDANCE. THE FORECAST CONTINUES TO CALL FOR THIS AREA OF FRESH TO STRONG TRADES TO EXPAND ACROSS THE CENTRAL CARIBBEAN THROUGH TONIGHT AND PERSISTING THROUGH FRI WITH SEAS BUILDING TO 10 TO 13 FT AS THE SUBTROPICAL RIDGE BUILDS TO THE NORTHEAST. MODERATE TO FRESH TRADES WILL PERSIST OVER THE TROPICAL N ATLC WITH SEAS 5 TO 8 FT.


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

MODEL PREFERENCE: BLEND OF 00 UTC ECMWF/GFS. 00 UTC TAFB NWPS FOR WAVE PARAMETERS. MEDIUM CONFIDENCE THEN LOW CONFIDENCE FRI AND SAT.

JET DYNAMICS ALOFT ASSOCIATED WITH AN UPPER TROUGH FROM THE NE GULF THROUGH THE NW CARIBBEAN CONTINUES TO ENHANCE NUMEROUS SHOWERS AND SCATTERED TSTMS ACROSS THE BAHAMAS...CUBA AND JUST OFFSHORE OF S FLORIDA. LATEST OBSERVATIONS INDICATE FRESH EASTERLY WINDS BETWEEN THE BAHAMAS AND STRAITS OF FLORIDA WITH A TIGHT PRES GRADIENT IN PLACE BETWEEN ATLC RIDGING AND TROUGHING OVER THE NW CARIBBEAN. SEAS ARE 5 TO 7 FT OVER MOST AREAS OUTSIDE THE BAHAMAS.

THE FORECAST ISSUE FOR THE REMAINDER OF THE WEEK CONTINUES TO BE THE DEVELOPMENT OF LOW PRES OVER THE NORTHERN BAHAMAS. RUN TO RUN CONSISTENCY AMONG THE MAJOR MODELS IS POOR...BUT LATEST TRENDS SHOW THE ECMWF AND GFS IN SLIGHTLY BETTER AGREEMENT ON POSITION...TIMING...AND INTENSITY THROUGH THU...WITH A TROUGH FORMING OVER THE CENTRAL BAHAMAS THIS MORNING...LOW PRES FORMING ALONG THE TROUGH OVER THE NORTHERN BAHAMAS EARLY WED...THEN SHIFTING NNE THROUGH THU REACHING NEAR 31N75W BY LATE THU. THE GFS HAS MODERATED SLIGHTLY AND DOES NOT SHOW RAPID DEEPENING IN OF THE LOW AS IN EARLY RUNS AND IS NOW MORE IN LINE WITH THE OPERATIONAL ECMWF. THE ECMWF IN TURN HAS SHIFTED ITS TRACK SLIGHTLY MORE TO THE EAST IN LINE WITH THE GFS. THE UKMET TRACK REMAINS EVEN FARTHER EAST. THE PATTERN BECOMES MORE UNCERTAIN LATE IN THE WEEK WITH THE GFS SHOWING A DUE WEST MOVEMENT ALONG 31N AND DEEPENING THE LOW SLIGHTLY...WITH THE ECMWF LARGELY DISSIPATING THE LOW. THE OFFICIAL FORECAST FOLLOWS A GFS/ECMWF BLEND WITH ONLY A SLIGHT EASTWARD TWEAK TO THE PREVIOUS FORECAST TRACK. ELSEWHERE MODERATE SE FLOW PERSIST ACROSS THE REGION IN THE WAKE OF THE TROUGH/LOW.

$$


.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 CHRISTENSEN. NATIONAL HURRICANE CENTER.

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