Special Features

Significant Rainfall over Central America: Periods of heavy rainfall and strong thunderstorms will occur over the southern Caribbean and into Costa Rica, Nicaragua, and Honduras through at least Thursday morning as very deep moisture persists over the region, supported by a surface low and an approaching tropical wave. Southeastern Nicaragua and northern Costa Rica are forecast to observe the highest amounts of rain today, while northeastern Nicaragua and Honduras are expected to observe their rainfall maxima on Wednesday.

Please refer to the local Weather Services in the region for more information.

Tropical Waves

The axis of a tropical wave is along 32W, south of 15N, moving westward around 15-20 kt. No significant convection is evident near this tropical wave.

A tropical wave is moving across the eastern Caribbean, south of the Mona Passage, moving westward at 20-25 kt. Some shower activity is near the wave axis.

Another tropical wave is over the central Caribbean with axis along 79W, south of 19N, moving westward at 20-25 kt. Scattered moderate convection is found immediately along the wave axis. This wave is forecast to reach the coasts of Nicaragua and Costa Rica on Wed, increasing the likelihood of showers and thunderstorms there.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic through the coast of Africa near 13N17W, then continues southwestward to 08N20W and then to 08N30W. The ITCZ extends from 09N35W to 06N57W. Scattered moderate convection is evident from 07N to 09N between 18W and 22W.

Gulf Of America

A diffluent pattern aloft and weak upper level shortwave are helping to induce scattered moderate convection over the western and central Gulf west of 85W. A broad ridge is centered north of the area over the eastern United States. A surface trough extends over the western Gulf from the central Bay of Campeche to the mouth of the Rio Grande. This pattern is supporting gentle to moderate E winds across the Gulf, with 3 to 5 ft seas from the Straits of Florida to the Yucatan Channel, and 1 to 3 ft seas elsewhere.

For the forecast, the broad ridge will continue to dominate the Gulf waters through Sat night. Moderate to fresh NE to E winds will pulse each afternoon and evening over the next several days north of the Yucatan Peninsula and in the eastern Bay of Campeche as a diurnal trough develops and tracks westward across the region. Gentle to moderate E to SE winds and slight to moderate seas can be expected elsewhere through Sat night.

Caribbean Sea

Two tropical waves are moving westward across the Caribbean Sea. Please, refer to the Tropical Waves section for more details.

Recent satellite derived wind data provide observations of fresh to strong E winds over the central and eastern Caribbean. These winds are the result of the pressure gradient between the Atlantic ridge and the Colombian Low. Moderate to fresh trades and moderate seas dominate the remainder of the basin. Elsewhere, a weak upper level shortwave is leading to the development of scattered moderate convection in the NW Caribbean, including the Yucatan Channel.

For the forecast, the pressure gradient between the Atlantic ridge and lower pressure over the SW Caribbean due to the E Pacific monsoon, the Colombian low and the passage of tropical waves will continue to support fresh to strong trades across most of the central and and SW Caribbean through Sun night. Winds are expected to reach near gale force off Colombia and in the Gulf of Venezuela Thu late afternoon and Thu night. Moderate to rough seas are expected within these winds. Elsewhere, moderate to fresh winds and moderate seas will prevail. By late Fri, winds may increase to strong speeds over the Gulf of Honduras due to the pressure gradient between the Atlantic ridge and a tropical wave that will be moving across Central America.

Atlantic Ocean

A weak pressure pattern remains in place across the subtropical western Atlantic. A trough reaches from near Bermuda to 26N71W. A few thunderstorms are active near the southern end of the trough. The pattern is supporting moderate to fresh NE to E trade winds south of 22N and west of 35W, with 6 to 9 ft seas. Gentle breezes and 3 to 6 ft seas are noted elsewhere west of 35W. Moderate to fresh NE winds are evident east of 35W, except for strong NE winds off the northwest coast of Africa. Seas are 7 to 9 ft east of 35W.

For the forecast west of 55W, the trough south of Bermuda will dissipate this evening, and the Atlantic ridge will strengthen. Under this weather pattern, moderate to fresh trades along with moderate seas are expected south of 25N through the weekend, with gentle to locally moderate winds elsewhere. Otherwise, fresh to strong E winds are expected N of Hispaniola Wed through Fri night.

Posted 1 hour, 50 minutes ago by NHC Forecaster Christensen