AXNT20 KNHC 181714

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
114 PM 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 1200 UTC surface analysis and satellite imagery through 1500 UTC.


The monsoon trough extends from the coast of Africa near 08N13W to 04N20W. The intertropical convergence zone continues from that position to 03N30W to the coast of Brazil near 03N51W. Scattered moderate convection is within 90 nm either side of the ITCZ between 23W and 38W.



A surface ridge extending from southwest Florida to the Texas coast is maintaining generally fair weather over the region. 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.


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 and a low over N Colombia is tightening the surface pressure gradient and maintaining moderate to fresh trade winds over the south central Caribbean, and gentle to moderate E to SE winds over the northern Caribbean. 25 kt winds and seas of 8 to 9 ft are off the coast of N Colombia. Scattered showers in the tradewind flow are S of Jamaica, 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.


A cold front extending from 31N46W to 26N60W will exit east of the area tonight. Seas are 8 to 11 ft in NW swell in vicinity of the front. Elsewhere, 1017 mb high pressure is centered near 25N69W, 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, 1025 mb high pressure centered near 29N26W 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

$$ Formosa