Special Features

Caribbean Gale Warning: The pressure gradient between the Bermuda High and the Colombian low will continue to support fresh to strong trades in the south-central and portions of the SW Caribbean through Mon night. Over the weekend, the ridge N of the region will shift southward, acting to increase the pressure gradient and accelerating the winds offshore Colombia and in the Gulf of Venezuela to near gale-force speed and to gale-force speed at night. Rough seas will prevail there, building to very rough at times this weekend with the increase in wind speed.

Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

Tropical Waves

A tropical wave is added to the 1200 UTC Unified Surface Analysis along 19W south 20N. Scattered to numerous moderate convection is noted from 08N to 11N between 15W and 21W, and from 11N to 14N between 19W and 22W.

A second tropical wave is along 38W S of 20N, and moving west at 15 to 20 kt. Scattered moderate convection is from 08N to 11N between 34W and 40W.

A third tropical wave is along 51W S of 20N, moving west at 15 to 20 kt. No significant convection is associated with this wave at this time.

A tropical wave is along northern Central America with axis along 89W. Please, see the TWDEP for more details.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic through the coast of Senegal near Dakar and continues southwestward to near 10N36W. The ITCZ extends from 09N40W to the coast of Venezuela near 09.5N61W. Aside from the convection associated with the tropical waves, limited convective activity is noted elsewhere.

Gulf Of America

High pressure of 1027 mb located near Bermuda extends a ridge westward across Florida into the Gulf region while a surface trough is analyzed over the central Bay of Campeche. Under this weather pattern, a light to gentle anticyclonic flow prevail, with the exception of gentle to moderate E to SE winds on the east side of the aforementioned trough. Slight to moderate seas are noted, with the highest seas in the Bay of Campeche. Numerous showers and thunderstorms continue to develop over parts of Florida, the Straits of Florida and the SE Gulf as an upper-level low remains over the eastern Gulf.

For the forecast, surface ridging from the Bermuda High will dominate across most of the Gulf through late Mon, supporting gentle to moderate E to SE winds N of 22N along with slight seas. Pulses of fresh winds will occur north and west of the Yucatan Peninsula and into the Bay of Campeche each night as a surface trough migrates from the Yucatan Peninsula to the SW Gulf. Slight to moderate seas are forecast for this portion of the basin through Mon night. In addition, a surface trough currently located over the western Atlantic and the Turks and Caicos Islands will continue to move across the Bahamas today and tonight before reaching Florida on Friday, leading to increased shower activity.

Caribbean Sea

The pressure gradient between a 1027 mb high located near Bermuda and the Colombian low continues to support fresh to strong trades over the south-central Caribbean, including the Gulf of Venezuela, along with moderate to rough seas. Moderate to locally fresh trades are elsewhere over the E Caribbean, the Gulf of Honduras and in the lee side of Cuba. Seas are generally moderate. In terms of shower activity, a surface trough starting to move across the Turks and Caicos Islands combined with an upper-level low spinning between Haiti and Jamaica is supporting scattered showers and tstms in the Windward Passage as well as in the vicinity of Jamaica and the Cayman Islands. The east extension of the E Pacific monsoon trough is supporting similar convective activity offshore NW Colombia and eastern Panama.

For the forecast, the pressure gradient between the Bermuda High and relatively lower pressure in northern South America will continue to support fresh to strong trades in the south-central and portions of the SW basin through Mon night. Over the weekend, the ridge N of the region will shift southward, acting to increase the pressure gradient and accelerating the winds offshore Colombia and in the Gulf of Venezuela to near gale-force speed and to gale-force speed at night. Rough seas will prevail there, building to very rough at times this weekend with the increase in wind speed. Fresh winds will pulse in the Gulf of Honduras and Windward Passage through the forecast period, except over the weekend when winds may pulse to strong speed. Otherwise, mainly moderate to fresh easterlies will prevail elsewhere.

Atlantic Ocean

As is typical for this time of the year, three tropical waves are moving between the west coast of Africa and the Lesser Antilles. About 60 tropical waves develop over North Africa each year.

A surface trough is analyzed over the western Atlantic, and runs from 28N69W to the Turks and Caicos Islands. Numerous showers and thunderstorms are associated with this trough covering the waters from 23N to 29N between 67W and 75W. Fresh to locally strong winds are on either side of the trough axis between 25N and 28N with seas of 8 to 10 ft based on scatterometer and altimeter data. The remainder of the Atlantic forecast waters is under the influence of high pressure, with the main center of 1027 mb situated near Bermuda. The pressure gradient between the Atlantic high pressure and lower pressures over NW Africa supports fresh to strong N to NE winds offshore Morocco and Western Sahara, including the Canary Islands with seas in the 6 to 8 ft range. Moderate to fresh NE winds are seen per scatterometer data ahead of the tropical wave located near 51W. Elsewhere gentle to moderate winds and moderate seas prevail.

For the forecast west of 55W, an upper-level low NE of Freeport will continue to support scattered showers and thunderstorms offshore E Florida and in the Great Bahama Bank through early this evening. A westward moving surface trough over the central and southern Bahamas offshores, will resume the shower activity across the Florida seaboard and offshores Fri morning before shifting west of the area Fri night into early Sat. Aside from the shower activity, the surface trough will bring fresh to locally strong winds and rough seas across the Bahamas offshores through tonight. Fresh E winds will prevail N of Hispaniola and in the approaches of the Windward Passage through the period, reaching strong speeds Sun night into Mon as the Bermuda High shifts southward.

Posted 0 minutes ago by NHC Forecaster Gr