Special Features

Caribbean Gale Warning: A tight pressure gradient between the subtropical ridge north of the islands and lower pressures in NW South America will support strong to near gale-force winds and rough seas in the central Caribbean during the next several days. A scatterometer pass from 0106 UTC confirmed gale-force winds occurring in the Gulf of Venezuela. Winds will increase to gale- force in the offshore waters of Colombia tonight. Seas are expected to build to around 14 ft with these winds. Please read the latest High Seas Forecast issued by the National Hurricane Center at website - https://www.nhc.gov/text/MIAHFSAT2.shtml

Tropical Waves

An eastern to central Atlantic tropical wave is along 37W, south of 20N, moving westward at around 20 kt. Scattered moderate convection is present from 08N to 11N between 33W and 37W.

A tropical wave has been relocated to near 56W, south of 20N and moving westward at around 20 kt. Scattered moderate convection is occurring from 12N to 15N between 54W and 58W.

An western Caribbean tropical wave is along 80W, south of 20N and moving quickly westward at around 15-20 kt. Any nearby convection is currently observed in the far eastern Tropical Pacific.

Monsoon Trough/ITCZ

The monsoon trough reaches the Atlantic from the northern coast of Mauritania at 21N16W to 08N30W and then to 12N42W. The ITCZ extends from 12N42W to 13N57W. In addition to the convection described in the Tropical Waves section above, scattered moderate convection is occurring along the W coast of Africa, and also from 065B to 08N between 28W and 32W.

Gulf Of America

High pressure of 1016 mb is remaining over the central Gulf near 26N86W within a broad ridge. As a result, gentle to moderate winds and slight seas prevail across the Gulf. Scattered moderate convection is occurring in the far NE Gulf, generated by a frontal boundary N of the region. Isolated moderate convection is also occurring ahead of a surface trough over the Yucatan Peninsula.

For the forecast, a surface ridge will remain in control of the weather pattern across the Gulf region promoting gentle to moderate winds for the next several days. The exception will be fresh NE winds off the northwest coast of the Yucatan peninsula nightly into the weekend. Scattered showers and thunderstorms will continue over the NE Gulf through the weekend as a frontal boundary remains just N of the area, and a very moist and unstable airmass prevails over region.

Caribbean Sea

Please see the Special Features section above for details on the Gale Warning in effect for the south-central Caribbean.

High pressure north of the islands forces fresh to near gale- force easterly trade winds and rough seas across the central Caribbean, with the strongest winds and highest seas to 12 ft occurring off NW Colombia. Moderate to fresh easterly breezes and moderate seas are found elsewhere from 11N to 18N. Across the remainder of the basin, moderate or weaker winds and slight to locally moderate seas prevail. Some convection is present near eastern Honduras and Nicaragua due to the proximity of a tropical wave and lower to mid level support.

For the forecast, a Gale Warning is in effect tonight for the offshore waters of Colombia and for the Gulf of Venezuela. Seas are expected to build to around 14 ft with these winds. Elsewhere across the central Caribbean, fresh to near-gale trades will continue to expand in coverage through early Fri as the pressure gradient between the Atlantic high pressure and low pressure in northern Colombian tightens. Mostly fresh trades will continue elsewhere south S of about 18N through the rest of the forecast period. Fresh to strong winds will pulse in the Gulf of Honduras tonight and Fri night, then to fresh speeds for the remainder of the period.

Atlantic Ocean

A frontal boundary is just north of the discussion waters. Associated scattered moderate isolated strong convection is north of 27N and west of 70W. Fresh to near gale force SW winds and 5 to 9 ft seas are in this region as well, highest winds and seas in areas of convection. In the central Atlantic, a surface trough is analyzed from 29N54W to 21N58W. Upper level divergence in the same region as this trough is leading to scattered showers and thunderstorms generally from 20N to 30N between 50W and 60W. Otherwise, a broad subtropical ridge continues to dominate much of the tropical Atlantic waters. Moderate to locally fresh trades are noted north of the monsoon trough and ITCZ to 20N, except fresh to strong N to NE winds from offshore Africa to the Cabo Verde Islands, as well as along the northern coast of Hispaniola and immediately east of the Lesser Antilles. Seas are 6 to 9 ft across the areas of fresh to strong winds. Moderate or weaker winds and moderate seas dominate the remainder of the tropical Atlantic waters.

For the forecast west of 55W, a surface ridge extending from near 25N65W to the Straits of Florida will change little through Sat night before it shifts northward to near 28N into early next week. The gradient between the ridge and a frontal boundary just NW of the forecast waters will continue to support fresh to strong SW winds along with scattered showers and thunderstorms north of 27N and west of 65W for the rest of the week and into the weekend. Fresh to strong trades will pulse just north of Hispaniola at night and into the mornings through the upcoming weekend.

Posted 0 minutes ago by NHC Forecaster Adams