000 AGXX40 KNHC 051834 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 234 PM EDT Mon Jun 5 2017 Marine Weather Discussion for the Gulf of Mexico, Caribbean Sea, and Tropical North Atlantic from 07N to 19N between 55W and 64W and the Southwest North Atlantic including the Bahamas ...GULF OF MEXICO... A broad area of low pressure and an associated surface lows and troughs are analyzed over the western Gulf of Mexico. One low of 1007 mb is near 23N93W, and the other low also of 1007 mb is near southwest Louisiana near 29N94W. Latest buoy observations show generally moderate southeast to south winds throughout, except for gentle to moderate winds over the NW Gulf where numerous strong thunderstorms, some with frequent lightning per lightning data, are observed. This activity is being triggered off by a rather potent mid to upper level low over eastern Texas embedded in a broad trough with multiple disturbances riding east-northeastward through its base. Winds in the vicinity of the low near 23N93W are observed to be gentle to moderate. The observations along with latest altimeter data reveal seas in the 3-5 ft range, except for lower seas of 2-3 ft in the far southern portion of the SW Gulf and 1-2 ft over eastern Gulf portion east of about 86W. The low near 23N93W will weaken as it continues to slowly lift north-northeast this afternoon, and become absorbed into the circulation of the low near 29N94W tonight. The culmination of this will be deepening low that moves east-northeast across the northern Gulf waters through Tuesday night, and reaches northern Florida on Wednesday. In its wake, a cold front will drop south over the northern gulf coast and enter the northern gulf on Wednesday night followed by mostly moderate northerly winds, with a few brief instance of fresh winds mainly over the coastal waters of the far northern Gulf. The cold front will then become stationary over the eastern and central Gulf waters during Thursday while weakening. The frontal remnants will then lift back north as a warm front Friday through Saturday night. Moderate to fresh southerly winds will continue to the east of the low as it makes its way across the Gulf, while gentle winds are expected north and west of this low under a weak pressure pattern. By Thursday night seas should be 1-3 ft throughout with little change into Saturday. The plume of deep moisture with resultant numerous showers and scattered thunderstorms that had been affecting much of the western and central Gulf the past few days has shifted to the eastern portion of the Gulf as well as the eastern part of the central Gulf. With the mid-upper trough over eastern Texas forecast to press eastward across the basin through early Thursday, expect the aforementioned moisture and shower and thunderstorm activity to shift eastward and should be confined to mostly east of the forecast waters, with some activity over the far southeast Gulf waters. As drier air filters in behind the mid-upper trough and cold front this should help keep shower and thunderstorm activity activity by late this week. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A high pressure ridge axis will extend from the central Atlantic to the Bahamas through the middle of this week, supporting fresh to strong easterly winds across the central Caribbean, and mainly moderate to fresh trades across the remainder of the Caribbean and the tropical Atlantic forecast waters. The ridge will then weaken as it shifts southeastward through the end of the week. This will weaken the gradient supporting the fresh to strong easterly winds, and winds will diminish to mainly gentle to moderate category over the Caribbean and tropical Atlantic forecast waters, except fresh north of Venezuela to about 15N. Scattered showers and isolated thunderstorms are possible over the extreme northwest part of the Caribbean Thursday through Friday as weakening Gulf of Mexico front approaches the Yucatan Channel and NW Cuba locations. A tropical wave axis near 57W early this afternoon is expected to move across the rest of the tropical Atlantic through tonight, then across the eastern Caribbean Tuesday through Wednesday followed by a surge of moisture with resultant scattered showers and thunderstorms. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A high pressure ridge axis extends along a POSITION from near 30N65W southwest to the central Bahamas and to southern Florida. Latest Ascat data and buoy observations show light to moderate east to southeast winds south of the ridge, and light to moderate south to southwest winds north of the ridge except for moderate to fresh southwest winds over the far northwest waters. Observed seas are in the 3-5 ft range east and northeast of the Bahamas, and 1-3 ft west of the Bahamas as well as north of the Bahamas and west of 78W. Models forecast the ridge axis to begin to weaken and slide southeastward on Tuesday in response to low pressure that tracks east-northeast from the Gulf of Mexico to across northern Florida and along the southeast U.S. coast. In the wake of the low, a rather strong cold front for this time of year will approach the the far northwest waters Wednesday, and move across the northern waters Wednesday night through early Friday while weakening. The gradient between the front and the aforementioned ridge has recently induced moderate to fresh southwest winds over the waters north of the Bahamas and west of 78W. These winds will expand east and southeastward through Wednesday night across much of the northwest waters and waters over the western portion of zone AMZ113. On Thursday, these winds should cover much of zone AMZ113 with pockets of fresh to strong winds there. These winds then clip the northwest portion of zone AMZ115 on Thursday night into Friday, and diminish to mainly moderate winds on Friday, and to gentle to moderate winds on Saturday. Seas are forecast to build to 8-10 ft over the northern section of zone AMZ113 on Thursday, then subside slightly to 7-9 ft Thursday night, to 5-7 ft Friday and to 3-5 ft all areas on Saturday except for lower seas of 1-2 ft continuing southwest of the Bahamas Deep moisture and resultant scattered showers and thunderstorms situated from the eastern Gulf of Mexico east-northeastward across Florida and the waters to near 73W will interact with mid-upper troughing that will shift eastward to the western portion of basin by the end of the week. Although the trough is expected to flatten out to some extent, enough moisture and instability in place will help trigger off additional shower and thunderstorm activity with reduced visibilities through the end of the week. Some of this activity is also expected to contain strong gusty winds, rough seas and possible frequent lightning. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.nhc.noaa.gov/marine $$ .Forecaster Aguirre. National Hurricane Center.