000 AGXX40 KNHC 111913 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 313 PM EDT Tue Apr 11 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... High pressure ridging extends from a 1029 mb high center, analyzed over the western Atlantic off the Mid-Atlantic coast, southwest to the northern portion of the Gulf. Latest buoy observations and satellite-derived winds show moderate to fresh east winds over the southern half of the eastern Gulf, gentle to moderate winds over the northeast waters and moderate to fresh southeast winds over the western waters. Moderate to locally fresh east winds are over the SW Gulf and Bay of Campeche. The buoys along with recent altimeter data reveal seas in the 4-6 ft range south of 28N, except for higher seas of 6-8 ft in he far southeast portion of the Gulf and Straits of Florida, and a pocket of 6-7 ft seas in the SW Gulf from 21N to 23N between 92W and 95W due to long southeast fetch and a long duration of east winds. The forecast will change very little from previous ones. The high pressure will be reinforced by a stronger area of high pressure that builds southward along the U.S. eastern seaboard from Wednesday through Sunday. This will lead to a tightening of the pressure gradient across the eastern part of the Gulf Thursday evening through Sunday, with winds increasing to the fresh to strong category over much of the eastern Gulf. A surface trough will develop over the Yucatan peninsula each evening. This trough will move westward into the eastern portion of the southwest Gulf waters late at night, then weaken and eventually dissipate as it moves over the western portion of the southwest Gulf during the morning. Fresh to strong east to southeast winds will follow in behind the trough until it dissipates. Water vapor imagery depicts a rather potent shortwave trough moving through central and eastern Texas early this afternoon. This feature may possibly bring some scattered showers and thunderstorms to portions of the NW Gulf later this afternoon and evening. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... The gradient remains fairly weak over the area as broad troughing has set up shop north of the Mona Passage, with the tail end of the trough extending south-southwest to near 13N70W. Latest buoy and scatterometer data shows mainly fresh northeast winds in the lee of Cuba and through Windward Passage. NE winds through the Windward Passage have at times gusted to near 30 kt during the morning and early afternoon. Similar gusts are expected at night through Friday night. Fresh to locally strong northeast to east winds are along the coast of NW Colombia. Elsewhere, The data shows gentle to moderate winds. The winds along the coast of Colombia will continue to pulse to fresh to strong through Friday night, then expand northward during the Saturday and Sunday periods as winds northeast in the lee of Cuba and just south of the Dominican Republic also pulse to fresh to strong. These winds will expand southwestward on Saturday and Sunday as the pressure gradient tightens due to strong high pressure that builds southward over the western Atlantic. Northeast winds through the Windward Passage and nearby waters are expected to be at strong intensity on a more steady basis Saturday through Sunday night, along with rough seas there. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The 18Z preliminary analysis has a stationary front along a position from near 28N65W to 27N67W where it becomes ill- defined to near 25N71W. A surface trough is along a position from near 27N66W to the Mona Passage. Strong high pressure is over the western half of the basin. The Ascat pass from 14Z this morning revealed a large swath of fresh to strong northeast winds north of about 27N and east of 73W. Satellite imagery is showing a fast moving low-level disturbance just approaching the Bahamas north of 24N. This feature is likely to be attended by quick moving scattered showers with gusty winds as it moves across the NW Bahamas through Wednesday morning. Models and ensembles members have come more in line in forecasting weak low pressure along the aforementioned surface trough on Wednesday. The low will initialize near 24N/25N and 67W/68W before it meanders around to the west, southwest and east through Thursday night before is accelerates northeastward on Friday to east of 65W Friday afternoon. The 12Z GFS and ECMWF are little more in agreement with position and timing. The UKMET is the slower solution with respect to motion of low to the northeast once it forms. The gradient will be very tight north of the low where winds are expected to be in the 20-30 kt range along with seas of up to 11 or 12 ft An area of stronger high pressure than what presently exists over the western will build east-southeast across the basin through Sunday. A resultant tight pressure gradient will significantly increase winds over just about the entire area through Sunday, with seas of 7-10 ft east of the Bahamas. Much higher seas are expected just to the east of 65W during the weekend as a large northwest swell component migrates to the southeast. Winds then diminish in northwest to southeast fashion Saturday night through Sunday night as the gradient relaxes. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.