Tropical Waves

A tropical wave is just west of the Cabo Verde Islands. Its axis is along 25W south of 17N. It is moving westward at 15 to 20 kt. Scattered moderate convection is noted from 05N to 09N between 20W and 27W. Scattered showers are likely over the Cabo Verde Islands and surrounding waters.

A well defined tropical wave is along 46W south of 17N, moving westward at around 20 kt. Scattered moderate to isolated strong convection is observed from 07N to 11N between 40W and 50W. This wave should reach the Lesser Antilles Wed evening, bringing fresh to strong trades and moderate to rough seas over the E Caribbean on Thu and Fri. Currently, seas of 6 to 8 ft are noted west of the wave axis based on altimeter data.

Another tropical wave is analyzed near 59W and extends southward into Guyana. It is moving westward at 15 kt. Scattered moderate convection is observed from 07N to 12N between 53W and 60. 5W. the wave will move across the Lesser Antilles this evening and tonight increasing the chances of rain. It is forecast to reach Puerto Rico on Wed bringing the chance of showers and thunderstorms.

The tropical wave previously located along 85W is relocated farther E along 80W based on tropical wave diagnostic and surface observations. Convection is limited near the wave axis.

Monsoon Trough Itcz

The monsoon trough axis enters the Atlantic through the coast of Mauritania near 18N16W and continues southwestward to 09N25W. The ITCZ extends from 08N27W to 08N44W to 09N57W. Most of the convective activity across the area is associated with the above mentioned tropical waves.

Gulf Of America

A weak ridge continues the dominate the Gulf region producing a gentle to moderate wind flow. Slight to moderate seas are noted with these winds. An upper-level low over the western Gulf is enhancing the development of showers and thunderstorms over parts of the basin, more concentrated over the west-central Bay of Campeche and near the Veracruz area.

For the forecast, the diurnal trough moving westward from the Yucatan peninsula will cause fresh to locally strong NE to E winds offshore of the peninsula nightly through the weekend. An upper- level low will cause scattered showers and isolated thunderstorms over the Gulf for the next couple of days. Elsewhere, winds and seas should be quiescent.

Caribbean Sea

Recent satellite derived wind and altimeter data provide observations of fresh to strong winds of 20 to 30 kt over central Caribbean with seas of up to 13 ft. In addition, buoy 42058 located near 14N76W is reporting seas up to 10 ft. These winds are the result of the pressure gradient between the Atlantic ridge and the Colombian Low. The scatterometer satellite data passes also reveal moderate to fresh trades across the eastern portion of the basin. Seas are moderate with these winds. Moderate to locally fresh NE to E winds are seen in the Gulf Honduras, where seas are 4 to 5 ft. Elsewhere, moderate or lighter winds along with slight to moderate seas are present. Scattered showers and thunderstorms are occurring over the western Caribbean, particularly W of 85W, including in the vicinity of the Gulf of Honduras. Patches of low level moisture, embedded in the trade wind flow, are moving westward across the area producing isolated to scattered passing showers.

For the forecast, the pressure gradient between the Bermuda-Azores High north of the area along with lower pressure over N South America will produce fresh to near gale trades over the central Caribbean for the next several days. Likewise, trades over the Gulf of Honduras will pulse to fresh to strong late afternoons and evenings through the weekend. A tropical wave centered near 59W currently will enhance showers and thunderstorms over the Windward Islands and the SE Caribbean for the next two days. Another stronger tropical wave should reach the Lesser Antilles Wed evening, bringing fresh to strong trades over the E Caribbean on Thu and Fri.

Atlantic Ocean

Three tropical waves are moving westward between W Africa and the Lesser Antilles. Please, see the Tropical Waves section for more details. The Saharan Air Layer (SAL) from CIMSS and the Geocolor satellite imagery show abundant African dust over this area into the eastern Caribbean.

As it is normal for this time of the year, the Bermuda-Azores High dominates the Atlantic forecast waters. Moderate to fresh winds are observed along the southern periphery of its associated ridge, with the exception of fresh to strong winds just north of Hispaniola. Light to gentle winds are near the ridge axis, mainly N of 25N. Seas are generally moderate with these winds. An upper- level low spinning between Hispaniola and the southeastern Bahamas is generating some shower activity.

For the forecast west of 55W, ridging associated with the Bermuda- Azores High will remain farther south than usual - near 27N. Waters north of 29N will have moderate to fresh W to SW winds for the next several days. Additionally, fresh to strong trades will continue just north of Hispaniola and the approaches to the Windward Passage through the weekend.

Posted about 3 hours ago by NHC Forecaster GR