AXNT20 KNHC 191042

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
642 AM EDT Mon Mar 19 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 1030 UTC.


Atlantic Gale Warning: Southerly flow will increase off northeast Florida late tonight and Tue ahead of a cold front moving into the region late Tue. SW to W winds will reach gale force north of 28N late Tue through Wed as the front moves east.


The monsoon trough extends from the coast of Africa near 07N11.5W to 05N20W. The intertropical convergence zone continues from that point to 05N45W. A few showers are noted within 30 nm on either side of the boundaries between 13W and 30W.



Weak ridging extends from southeast Florida to the north central Gulf, supporting light to gentle southeast winds over most of the region. Areas of fog and low stratus are evident this morning in satellite imagery and surface observations across the northwest Gulf and portions of the north central Gulf.

The ridge is shifting east ahead of a cold front that will move off the Texas coast later today. The front will extend from the Florida Big Bend area to Veracruz Mexico tonight, 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 Thu as high pressure follows the front across the northern Gulf.


A pair of scatterometer passes from 03 UTC confirmed a large area of fresh to strong trade winds off Colombia, and a smaller area of strong winds south of the Bay Islands off central Honduras. Seas are reaching 8 ft off Colombia, but are generally 4 to 6 ft in the eastern and central Caribbean and tropical north Atlantic, and 2 to 4 ft in the northwest Caribbean. No significant convection is noted.

Building high pressure north of the region will 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 cold front will pass through the Yucatan Basin by early Wed, then drift south and stall from the Windward Passage to central Honduras Fri, followed by fresh northerly flow and seas building to 7 ft.

Undersea volcano Kick em Jenny, 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 or 3.1 nm exclusion zone around Kick em Jenny. Please see www.nadma.gd for additional information.


Please see Special Features section for information on the developing gale warning in the Atlantic.

A weak cold front extending from near Bermuda to northeast Florida will shift eastward and weaken through Tue. A few thunderstorms are noted along the frontal boundary north of 29N between 60W and 65W. Farther south, weak ridging is supporting gentle breezes west of 60W, with 4 to 6 ft seas in open waters east of 75W, due mainly to residual northerly swell.

The next cold front will move off the coast late Tue, associated with a deep surface low moving off the mid-Atlantic coast. The supporting upper trough will become negatively tilted as it emerges off the coast. This will interact with the Gulf Stream to support scattered thunderstorms Tue night off the northeast coast of Florida. In addition to the gales, strong westerly winds and seas ranging from 8 ft to as high as 17 ft will prevail north of 27N and west of 60W into Wed night.

Winds and seas will diminish Thu as the front reaches from Bermuda to the Windward Passage, before stalling and weakening through late week. A weaker front will move eastward north of 28N Thu night into Fri.

Over the eastern Atlantic, 1025 mb high pressure is centered near 30N27W, supporting gentle to moderate NE to E winds over the subtropics and moderate to fresh trades in the deep tropics. An upper trough is noted along 28W north of 05N, supporting a few small areas of modest convection along the monsoon trough and ITCZ. Recent altimeter satellite passes indicate seas are still 8 to 12 ft north of 05N, likely in persistent long period NW swell.

For additional information please visit http://www.hurricanes.gov/marine

$$ Christensen