000 AGXX40 KNHC 301021 AAA MIMATS Marine Weather Discussion...UPDATED NWS National Hurricane Center Miami FL 621 AM EDT Thu Mar 30 2017 ...updated for weather in Gulf of Mexico... 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... The gradient associated with weak high pressure that extends from the Western Atlantic to the central gulf is allowing for light to moderate east to southeast winds over the eastern gulf waters. Over the central gulf, southeast winds have increased since yesterday to fresh to strong as the pressure gradient between the ridge and a cold front just inland the Texas coast has tightened. The cold front is preceded by a trough that extends from near Lake Charles Louisiana to near 27N96W. Latest satellite imagery and current NWS radar imagery shows a quite an impressive developing line of numerous strong thunderstorms along and within 50 nm east of the trough containing numerous lightining strikes. Some of this activity might reach the strong to severe limits later today as it translates eastward across the waters mainly north of about 27N. The cold front will move off the coast around 09Z this morning, and quickly move across the northwest waters through this morning, the central waters this afternoon and the eastern waters late tonight through while weakening. Before the front weakens, fresh to strong southerly winds will precede the front mainly over the far northern waters today while the same type of winds over the central waters as stated earlier diminish to moderate winds. The gradient associated with a thermal trough has brought an increase to southeast winds over the eastern Bay of Campeche, and waters just northwest of the Yucatan Peninsula. These winds will diminish late this morning. This process of the thermal trough with increasing southeast winds will repeat each night through Saturday night. Otherwise, plenty of atmospheric instability associated with upper level dynamics is expected to bring numerous showers and thunderstorms, some capable of producing strong gusty winds and tough seas, ahead of the front through Friday. Another area of low pressure will develop over the southern Plains Friday, and move over the southern United States during Saturday through Sunday period. The pressure gradient between the low and Atlantic high pressure ridging extending to the eastern waters will once again bring an increase to southeast winds over much of the central and western gulf. These winds are forecast to increase to mainly the strong category with seas around 8 or 9 ft during the upcoming weekend. The cold front associated with this next round of low pressure is forecast to move off the Texas coast on Sunday night. This front will also quickly move across the basin reaching from near the far western Florida panhandle to the eastern Bay of Campeche early on Monday, and from near west- central Florida to the northeast Yucatan Peninsula by late on Monday. Mostly strong southerly winds are likely to precede the front, with a good possibility of a squall line developing out ahead of it. There is a chance for southerly winds to near gale force over some portions of the north-central waters on Monday. Scattered showers and thunderstorms with strong gusty winds and frequent lightning are very possible along the front or squall line. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Gentle to moderate trades continue over the Caribbean due to the continuation of a weak pressure pattern. However, high pressure building over the SW N Atlc will allow for the trades to become fresh at night mainly over the central and south-central Caribbean while fresh to strong winds are forecast for the Gulf of Honduras and along the coast of Colombia at night. This pattern of moderate to fresh trades over the majority of the Caribbean and fresh to strong winds over the Gulf of Honduras and Colombia coast will persist through the upcoming weekend. Over the tropical Atlantic waters, a weakening cold front is analyzed from near 22N55W southwest to the vicinity of the Leeward Islands. A very weak pressure gradient south of the front is sustaining gentle to light easterly flow over just about the entire Tropical North Atlantic zones, except for moderate trades in the southeast portion of these zones. The front is forecast to continue to slowly move southeastward while gradually dissipating through Friday as it loses its upper support. Northerly swell is decaying in the Tropical North Atlantic, however wave model guidance is suggesting that quite an impressive and extensive batch of long period northerly swell will begin to infiltrate the Tropical North Atlantic waters starting on Saturday. This northerly swell will propagate through all of the Tropical North Atlantic zones into Monday while inducing combined sea state of 8-11 ft. By late on Monday, the bulk of the swell energy will be confined to south of about 16N, with combined sea state of around 8-10 ft. ...SW N ATLANTIC INCLUDING THE BAHAMAS... ...A very progressive pattern in play going into early April... The northeast swell in the eastern portion of zone AMZ115 has subsided to 5-7 ft. This respite will be short-lived as yet another set of long-period northerly swell will move into the northeast portion of zone AMZ115 beginning this evening, with seas of 6-9 ft. This swell will propagate through all of the eastern portion of the basin into Sunday night, with combined sea state peaking to around 10 ft before subsiding to 8 ft on Sunday and further to 7 ft on Monday. Weak high pressure remains over the basin as a rather weak cold front has moved into the far northern waters from near 31N66W to 29N75W and stationary northwest to the coast of the northeast Georgia. The front is followed by generally fresh northwest to north winds, while moderate to locally fresh northeast to east winds are north of the stationary front. The cold front will move southeast of the zones AMZ115 and ANZ121 tonight, while the stationary front becomes diffuse. Its remnants will lift northward as a warm front through Friday. This will take place as a cold front advances across the southeast U.S. This next cold front will emerge off the southeast U.S. coast on Friday evening. The front will begin to push the aforementioned high pressure over the western part of the basin eastward as it progress over the northwest waters Friday night and over the north-central waters on Saturday. A very tight gradient between the front and the high pressure will develop strong southerly winds over much of zone AMZ111 on Friday, with seas of 8-9 ft. This strong southerly flow will shift to the northwest corner of zone AMZ113 on Friday afternoon and the remainder of the far northern waters through early on Sunday at which point strong west to northwest winds will make theier way into much of the northeast portion of zone AMZ115 as the front exits the forecast waters. High pressure in the wake of the front will slide eastward to the northeast part of the forecast waters by late on Monday as rapidly deepening low pressure that global model consensus depicts will track northeastward across northern Alabama and Tennessee. A strengthening pressure gradient covering a large area of the southeastern U.S. and corresponding offshore waters will lead to a significant increase of southerly flow over the northwest waters on Monday along with building seas. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.