Special Features

Periods of heavy rainfall and strong thunderstorms will occur over the southern Caribbean and into Nicaragua and Costa Rica 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 is expected to observe its 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 28W, south of 16N, moving westward around 15 kt. Scattered moderate convection is noted where the wave meets the monsoon trough.

A tropical wave is moving across the eastern Caribbean. Its axis is along 64W, south of 17N, moving westward at 20 to 25 kt. Some shower activity is near the wave axis. The wave appears to enhance convection over eastern Venezuela.

A second tropical is over the central Caribbean with axis along 73W,south of 18N, moving quickly westward at 20 to 25 kt. Scattered moderate convection is found from 13N to 15N between 70W and 76W. This wave is forecast to reach Central America on Wed, increasing the likelihood of showers and tstms there.

The tropical wave previously located along 79W is not longer discernible on TPW product and satellite imagery, and now appears to be part of the broad circulation currently observed over the far eastern Pacific and the SW Caribbean.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic Ocean through the coast of Mauritania near 19N16W, then continues southwestward to 09N31W. The ITCZ extends from 09N31W to 07N45W to the coast of Guyana near 07N58W. Scattered moderate convection is occurring from 06N to 10N between 13W and 20W, and south of 08N west of 50W.

Gulf Of America

A ridge remains in control of the weather pattern across the Gulf region producing in general gentle to moderate E to SE winds. The exception are fresh to strong E winds to the W of the Yucatan Penninsula due to local effects associated with a thermal trough, and in the Straits of Florida where scatterometer data indicate fresh to strong E winds, particularly from the coast of western Cuba to about 24.5N between 81W and 84W. Seas are 6 ft within these winds. Elsewhere, seas are 3 to 5 ft, except 1 to 3 ft in the NE Gulf. Showers, with embedded thunderstorms, are observed along the coast of Mexico, particularly between Tampico and Veracruz, including also the western Bay of Campeche. A diffluent pattern aloft is helping to induce this convective activity.

For the forecast, a ridge extending from the SW N Atlantic waters 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 winds over the south-central Caribbean, on either side of the Lesser Antilles, including waters between the islands, and E of the Lesser Antilles to about 45W where rough seas persist. 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. Convection continues to flare-up over the SW Caribbean in association with a northward displacement of the eastern Pacific monsoon trough and a broad area of low pressure extending from the SW Caribbean into the eastern Pacific region.

For the forecast, the pressure between the Atlantic ridge and the Colombian low will continue to support fresh to strong trades across most of the east and central Caribbean through the week. Winds are expected to reach near gale force off Colombia and in the Gulf of Venezuela by Thu night. Moderate to rough seas are expected within these winds. Elsewhere, moderate to fresh winds and moderate seas will prevail. By late this week, winds may increase to strong speeds over the Gulf of Honduras due to the pressure gradient between the Atlantic ridge and a broad area of low pressure currently located a few hundred miles offshore of Central America. This system has the potential of tropical cyclone formation.

Atlantic Ocean

A surface trough extends southwestward from a 1019 mb gale center (Invest 90L) located north of the forecast area near 35N51W to near the Turks and Caicos Islands. Scattered moderate convection is near the trough axis, mainly from 23N to 30N. High pressure of 1029 mb located SW of the Azores near 34N35W dominates the remainder of the forecast area, with another high pressure of 1023 mb situated E of northern Florida near 30N78W. Scatterometer and altimeter data indicate fresh to strong trades and rough seas over the tropical Atlantic between 45W and the Lesser Antilles, and N of 20N E of 35W, including between the Canary Islands. Fresh to locally strong E winds are noted N of Puerto Rico and Hispaniola, including approaches to the Windward Passage. Elsewhere, moderate or weaker winds and slight to moderate seas prevail.

For the forecast west of 55W, the aforementioned surface trough will dissipate today, and the Atlantic high pressure will then extend westward towards the Florida peninsula. Under this weather pattern, moderate to fresh trades along with moderate to locally rough seas are expected south of 25N over the next few days, with gentle to locally moderate winds elsewhere. Otherwise, fresh to locally strong E winds are expected N of Hispaniola Wed through Fri.

Posted 0 minutes ago by NHC Forecaster Gr