Monsoon Trough/ITCZ

The monsoon trough axis enters the eastern Atlantic through the southern Guinea-Bissau coast near 12N16.5W and continues southwestward to 03N27W, where it transitions to the ITCZ. The ITCZ then continues southwestward to the coast of Brazil near 01S47W. Scattered moderate to strong convection is occurring from the Equator to 07N between 00W and 20W. Scattered moderate convection is occurring within 150 NM of both the monsoon trough and ITCZ between 20W and 28W, and from 02N to 04.5N between 45W and 47W.

A portion of the East Pacific monsoon trough enters the SW Caribbean near 10N83W and extends to the Colombia Low analyzed near 10.5N74W. Scattered moderate convection is observed in the SW Caribbean S of 11.5N.

Gulf Of America

A surface trough is analyzed along the Mexican coast from 21.5N97.5W to south of Veracruz, Mexico near 18N96.5W. Elsewhere, an Atlantic ridge extends from the Bermuda high W-SW across the northern Gulf. This pattern is producing moderate to fresh E-SE to S winds across much of the basin, with strongest winds across NW portions. Seas are 5 to 7 ft W and NW portions, 4 to 6 ft central portions and Straits of Florida and 3 to 4 ft NE portions. Fair weather dominates the basin, with a few showers across central portions, and elevated showers across the central Louisiana coastal waters.

For the forecast, a ridge will continue to dominate the Gulf waters this week. Its associated gradient will maintain moderate to fresh east to southeast winds over the basin for the next few days. East winds will pulse to strong speeds north of the Yucatan peninsula and over the Bay of Campeche at tonight through Fri night in association with a diurnal trough. Moderate to fresh east winds and moderate seas are expected over the Straits of Florida through Thu night. Winds elsewhere will begin to diminish Fri and into the weekend. Looking ahead, a weak cold front may reach the NE Gulf Sat night.

Caribbean Sea

Aside from the convection mentioned in the Monsoon Trough/ITCZ section, upper level troughing extending from the western Atlantic southwestward across the central Caribbean supports scattered showers and a few thunderstorms N of 14N and E of 76W. Recent scatterometer data indicated moderate to fresh E to NE winds prevailing across the central and W Caribbean, with gentle to moderate trades elsewhere E of 70W. Seas are generally 4 to 6 ft W of 70W, and 2 to 4 ft E of 70W.

For the forecast, high pressure north of the basin combined with the Colombian Low will support pulsing fresh to strong trades at night through the Windward Passage and south of Cuba through Thu night, before high pressure weakens and shifts northeastward into the weekend. Elsewhere, rather quiet conditions are expected over the forecast waters through the weekend. Moisture ahead of a dissipating frontal boundary just north of the Greater Antilles will produce periods of active weather across the NE Caribbean and islands tonight through Sat.

Atlantic Ocean

A cold front enters the discussion waters near 31N49W and extends southwestward to 27.5N58W where it becomes a stationary front continuing southwestward to near the north coast of Hispaniola along 70W. North of the front, a 1023 mb Bermuda High resides. A persistent trough is analyzed from 27N53W southwestward to the northern Leeward Islands. Scattered to locally numerous moderate convection is observed ahead of both of these features, in a region N of 24N between 48W and the cold front along 54W. Scattered showers are also observed about the trough, south and southwestward to the NE Caribbean Islands. Mostly fresh to locally strong NE winds are north of the front and extend through the Bahamas and Cuba, including through the Florida Straits. Seas there are 6 to 9 ft east of the Bahamas. Winds between the front and 54W and light to gentle.

To the east, a 1028 mb high is centered N of the area near 36N34W and extends a broad ridge southward across the remainder of the Atlantic. Moderate to fresh trade winds dominates these waters E of 54. Seas there are 5 to 9 ft in N to NE swell, except 9 to 12 ft north of 28N and east of 28W

For the forecast west of 55W, the stationary front will begin to weaken Thu. A surface trough is east of the front and extends to near Guadeloupe in the Lesser Antilles. High pressure west of these features will remain about stationary through Thu, then begin to shift eastward into the weekend. The front and trough are forecast to merge near 55W on Thu. A weak low may develop along the trough axis on Fri. This will induce fresh northeast winds north of 27N and east of 65W from Fri morning into the weekend. Looking ahead, a weak cold front may emerge off the U.S. Southeastern coast late Sat night into Sun.

Posted 23 hours ago by NHC Forecaster Stripling