Monsoon Trough/ITCZ

The monsoon trough extends from Guinea- Bissau near 12N16W to 06N20W to 02N30W. The ITCZ continues from 02N30W to 01N50W. Scattered moderate convection is active from 00n to 07N between east of 30W.

Gulf Of Mexico

Weak high pressure is centered over the northeast Gulf. Latest scatterometer and buoy data indicate gentle to moderate SE winds across the central and western Gulf, between the high pressure and lower pressure over Texas and Mexico. Combined seas in this area are 3 to 5 ft. The high pressure is supporting generally calm to light breezes across the eastern Gulf, where seas are 1 to 3 ft. A few showers and thunderstorms are active over the coastal waters off the Sabine Pass in the northwest Gulf.

For the forecast, the pressure gradient between the ridge and lower pressures in Texas and Mexico will tighten, and fresh to strong pulsing winds in the western half of the Gulf will develop tonight into the weekend. Moderate or weaker winds will prevail in the eastern half of the basin. Winds will pulse to strong speeds nightly near and to the NW of the Yucatan Peninsula due to local effects induced by a thermal trough.

Caribbean Sea

Recent buoy observations and scatterometer data indicates moderate to fresh trade winds over the south-central Caribbean off northeast Colombia and northwest Venezuela, and fresh winds funneling off the coast of Cabo Beata on the south coast of Hispaniola. These winds are active between weak high pressure centered north of the area near Bermuda and lower pressure over Colombia. Combined seas are 3 to 5 ft in this area. Gentle to moderate easterly winds are noted elsewhere with 2 to 4 ft seas. Scattered showers and thunderstorms are active over teh Windward Passage ahead of an upper trough, but elsewhere no significant shower or thunderstorm activity is noted at this time.

For the forecast, the high pressure north of the area is expected to slide eastward and weaken on Thu, reducing the areal coverage and limiting these winds to the SE Caribbean by Thu evening. Showers and thunderstorms currently affecting the Mona and Windward Passages as well as Hispaniola adjacent waters will amplify tonight into Thu as a surface trough develops N of Hispaniola. The pressure gradient between this feature and a weak ridge will also support moderate to fresh NE winds in the lee Cuba, NW Caribbean and the Windward Passage Thu night into Sat night. Gentle to moderate trades are expected basin-wide the remainder forecast period, except for fresh winds in the south- central Caribbean.

Atlantic Ocean

Broad high pressure centered near Bermuda dominates the western Atlantic. A recent scatterometer satellite pass indicated fresh E winds south of the high pressure along the north coast of Hispaniola. Moderate E to SE winds are evident elsewhere south of 24N and west of 55W. Recent altimeter and buoy data show combined seas of 5 to 8 ft in this area. Light to gentle breezes and 3 to 5 ft combined seas are noted closer into the ridge, north of 24N and west of 55W. Scattered showers and thunderstorms are active across the southern Bahamas, ahead of an upper trough approaching from the west.

A pair of cold fronts are analyzed farther east. One from 30N45W to 25N60W, and the other from Azores to 30N34W to 26N38W. An earlier scatterometer satellite pass indicated fresh to strong SW winds within 90 nm east of the first front, north of 28N. Concurrent altimeter data indicated combined seas of 6 to 8 ft near these fronts, north of 28N. Gentle to moderate winds and 4 to 6 ft seas are evident elsewhere west of 35W. Farther east, fresh to strong NE winds and 5 to 8 ft seas are noted over the eastern Atlantic east of 35W, to the south of strong high pressure centered east of the Azores.

For the forecast west of 55W, the high pressure is expected to slide eastward and weaken on Thu while a surface trough develops just N of Hispaniola. The pressure gradient between the ridge and the trough will support E-SE winds of the same magnitude E of the trough and NE-E moderate to fresh winds W of the trough. The trough will also amplify the area of showers and tstms currently affecting the southern Bahamas and the Great Bahama Bank. The trough is forecast to become a weak low, which will track NE Fri through Sat, and open back into a trough while exiting the area Sat afternoon. Locally strong and gusty winds are possible to develop in the northern semicircle of the low within this period.

Posted 0 minutes ago by NHC Forecaster Christensen