Special Features

Western and Central Atlantic Gale Warnings/Significant Swell: A cold front is analyzed from near 31N53W southwestward to 26N63W to 25N70W and to the central Bahamas. Latest scatterometer satellite data passes reveal west to northwest winds of 30 to 45 kt west of the front north of 27N and to near a line from 31N71W to 27N65W. Seas with these winds are in the range of 20 to 30 ft, with the highest of the seas north of 29N between 54W and 66W. Sofar Ocean Spotter buoys in the area along with recent altimeter satellite passes indicate these very high seas behind the front. There was an instance this afternoon of a Sofar Ocean Spotter buoy reporting 31 ft seas at location of 30N60W. Very rough seas in excess of 12 ft extend well to the south of these gale winds to near 23N and between 55W and 71W due to the occurrence of significant northwest swell. Fresh to near gale-force southwest winds, with frequent gusts to gale-force are east of the front to a line roughly from 30N35W to 24N50W to 24N62W. Seas with these winds are in the range of 8 to 12 ft in northwest swell, except for higher seas of 12 to 16 ft north of 26N. The front is forecast to reach from near 31N43W to 18N62W by early Mon afternoon. West to northwest strong to near gale-force winds are expected at that time west of the front to near 62W, and north of 26N along with seas of 17 to 26 ft in northwest swell. Fresh to strong winds will be north of 25N between the front and 71W at that time along with seas of 14 to 23 ft in northwest swell. The winds ahead of the front with frequent gusts to gale-force will diminish early on Mon. Meanwhile, the gale-force winds behind the front will diminish to fresh to strong speeds by early Tue morning. Very rough seas generated by these winds will propagate southeastward impacting most of the waters north of about 16N and northeast and east of the Bahamas through the middle of the week. The very rough seas are likely to finally subside to just below 12 ft by early Wed evening. Mariners are urged to stay up to date with the latest forecasts.

Please read the latest High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details on these events.

Monsoon Trough/ITCZ

The monsoon trough axis enters the Atlantic through the coast of Liberia near 06.5N11W and extends southwestward to near 03N18W, where it transitions to the ITCZ that continues to 01N30W to 01N40W and to the coast of Brazil near 02N50W. Scattered moderate convection is within 120 nm north of the ITCZ between 33W-41W, and also south of the ITCZ between 36W-44W.

Gulf Of America

High pressure of 1025 mb is centered over the west-central Gulf near 24N92W, with a ridge stretching south-southeastward to across southeastern Mexico. Seas are in the range of 2 to 4 ft, with the highest of the seas located in the eastern Gulf, and in and near the Yucatan Channel. Occasional seas to 5 ft are in the Straits of Florida.

For the forecast, high pressure will dominate the weather pattern over the basin through at least the middle of the week generally maintaining a gentle to moderate anticyclonic flow throughout. Fresh to strong northeast to east winds are expected mainly at night just west of the Yucatan Peninsula and over the far western waters. Slight to moderate seas will prevail through at least the middle of the week.

Caribbean Sea

Latest scatterometer satellite data passes indicate fresh to strong north to northeast winds roughly between 75W and 83W. Seas with these winds are in the range of 5 to 7 ft, except for slightly higher seas of 6 to 8 ft south of 15N as noted in earlier altimeter satellite passes. Elsewhere across the basin, gentle to moderate northeast to east winds are present, except for fresh north to northeast winds north of 15N between 68W and 71W, including the Mona Passage and also north of 15N between 75W and 77W, including the Windward Passage. Seas elsewhere are in the range of 3 to 5 ft, except for higher seas of 5 to 7 ft north of 15N between 68W and 76W and seas of 4 to 6 ft elsewhere north of 15N east of 80W. Lower seas of 2 to 4 ft are in the Gulf of Honduras and north of 20N west 77W.

The remnants of a frontal boundary are analyzed as a trough from the Leeward Islands to the coast of Colombia near 11N74W. Isolated showers are possible near the trough east of 71W.

For the forecast, the aforementioned frontal boundary will be reinforced by a cold front tonight into Mon, with the combined front sliding east of the Leeward Islands by Tue. Winds will increase in the wake of the front, becoming strong initially offshore Colombia and Hispaniola tonight, then expanding to much of the central Caribbean, including the Windward Passage, Mon through Wed, as high pressure in the western Atlantic builds southward toward the area. Rough seas will accompany these strong winds. In addition, large northwest to north swell will impact the Mona Passage, Anegada Passage, and tropical N Atlantic waters tonight into Wed creating hazardous seas.

Atlantic Ocean

Please see the Special Features section for details on a gale warning and significant swell in the western and central Atlantic.

A remnant frontal boundary trough is analyzed from near 31N43W southwestward to 24N55W and continues to the Leeward Islands. Conditions east of this boundary are as described in the Special Features section in association with the cold front that extends from near 31N53W southwestward to 26N63W to 25N70W and to the central Bahamas. For areas outside of those described above in the Special Features section, the majority of the Atlantic waters south of 20N are dominated by moderate to fresh trades and moderate seas, with the exception of locally fresh to strong northeast winds near Cabo Verde. To the north of 20N and east of 35W, winds are generally gentle to moderate along with moderate seas as high pressure of 1025 mb located at 28N23W controls the weather pattern over this part of the Atlantic. Isolated weak showers are within 60 nm either side of the trough north of 26N.

For the forecast W of 55W, except as stated above under Special Features, the Special Features cold front as described above will merge tonight with the remnants of a frontal boundary that runs from 23N55W to the Leeward Islands. The merged front will remain across the southeastern forecast waters on Mon, then move east of 55W by Mon night, allowing winds to gradually diminish. Very rough seas will continue across most of the waters east of 77W through Tue gradually subsiding from west to east.

Posted 1 hour, 50 minutes ago by NHC Forecaster Aguirre