000 AXNT20 KNHC 181003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 603 AM EDT Sun Mar 18 2018 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 08N13W to 03N25W. The intertropical convergence zone continues from that position to the coast of Brazil near 03N51W. Scattered moderate convection is within 90 on either side of the ITCZ between 25W and 35W. ...DISCUSSION... GULF OF MEXICO... A surface ridge extending from southwest Florida to the Texas coast is maintaining generally fair weather over the region. A few platforms over the northwest Gulf continue to report sea fog with visibilities 4 to 6 nm, but otherwise visibilities remain unrestricted and there is no significant rain or shower activity. Winds are nearly calm over the northeast Gulf near the center of the high pressure with gentle to moderate southeast winds elsewhere. Seas are 1 to 3 ft in the eastern Gulf, and 3 to 5 ft in the western Gulf. The ridge over the northern Gulf will shift E through tonight ahead of a cold front moving off the Texas coast Mon. The front will extend from the Florida Big Bend area to Veracruz Mexico early Tue, just as a reinforcing push of cold air moves off the Texas coast. The reinforcing front overtakes the first front late Tue, accompanied by strong winds and building seas over the northern Gulf. The merged front sweeps southeast of the Gulf by early Wed. Winds and seas diminish across the Gulf through late Wed as high pressure follows the front across the northern Gulf. CARIBBEAN SEA... The undersea volcano Kick 'em Jenny, located north of Grenada near 12.18N 61.38W, is in a state of unrest. The government of Grenada advises mariners to observe a 5 km / 3.1 nm exclusion zone around Kick 'em Jenny. Please see http://nadma.gd for further information. High pressure east of the Bahamas is maintain moderate to fresh trade winds over the south central Caribbean, and gentle to moderate E to SE winds over the northern Caribbean. An altimeter satellite pass from 23 UTC indicated seas in excess of 8 ft off Colombia, an indication trade winds are stronger off northeast Colombia, and will possibly reach near gale force through early morning due to the added effect of drainage flow. Seas are 2 to 4 ft in the northwest Caribbean, and 4 to 6 ft elsewhere. Regional radar in the eastern Caribbean shows a few small showers in the trade wind flow over the Windward Islands, but otherwise no significant rainfall is noted. High pressure north of the region will continue to support fresh to locally strong trades across the south central Caribbean the next several days, except increasing to near gale force along the northwest coast of Colombia during the overnight hours. A weakening cold front will pass through the Yucatan Basin late Tue night. The pressure gradient will tighten ahead of the front, allowing fresh to strong E to SE winds off the central coast of Honduras by Mon night. ATLANTIC OCEAN... A cold front extending from 31N50W to 27N63W to 30N70W will exit east of the area later today. While strong winds are no longer evident north of the front, recent buoy observations and altimeter satellite data indicate seas 8 to 11 ft, likely in NW swell. Elsewhere, 1019 mb high pressure is centered near 27N70W, maintaining light to gentle breezes from 22N to 28N, with fresh SW winds north of 28N. The SW winds north of 28N will increase tonight ahead of another front moving across the waters north of 28N Mon. Southerly winds will increase to fresh to strong off northeast Florida and north of the Bahamas late Mon, then increasing further to near gale to gale force north of 28N with building seas late Tue through Wed as low pressure moves off the Carolina coast. A trailing cold front will sweep eastward, reaching from Bermuda to eastern Cuba by Wed night. Looking ahead, the front will drift east through late week, with 7 to 9 ft NW swell propagating across most of the open waters east of 55W. Over the eastern Atlantic, 1023 mb high pressure centered near 29N35W is maintaining gentle to moderate flow over the subtropics and moderate to fresh trades over the deep tropics. Persistent long period NW swell continues to propagate into the region from the north central Atlantic, maintaining 8 to 12 ft seas mainly east of 55W, as noted in recent altimeter satellite passes. An upper trough reaching from roughly the Canary Islands through the Cabo Verde Islands to 06N30W is interacting with trade wind convergence in the lower levels to support scattered showers and a few thunderstorms within 90 nm of the intertropical convergence zone between 25W and 35W. For additional information please visit http://www.hurricanes.gov/marine $$ Christensen