Monsoon Trough Itcz

A monsoon trough runs westward from the Sierra Leone Coast just south of Freetown to near 07N55W, then continues as an ITCZ from 07N55W to 07N30W to 06N48W. Widely scattered moderate to isolated strong convection is present near these features from 03N to 10N between the Sierra Leone/Liberia coast and 44W.

Aided by divergent flow aloft, the eastern end of the East Pacific monsoon trough is causing numerous heavy showers and isolated strong thunderstorms over the Caribbean waters near Costa Rica and western Panama.

Gulf Of America

A cold front extends southwestward from the Florida Panhandle near Saint Joseph Bay to southwest of New Orleans at 27N93W, then continues as a stationary front to beyond the southern tip of Texas. Patchy showers are occurring up to 40 nm along either side of this boundary. A surface trough is causing scattered moderate to isolated strong convection across the west-central Gulf, and at the southern Bay of Campeche. Fresh to strong NE to ENE winds and seas of 6 to 8 ft are evident near and beyond north of the front. Fresh to strong NE winds and seas of 3 to 5 ft are present at the eastern Bay of Campeche. Gentle to moderate NNE to NE winds and seas of 2 to 6 ft prevail for the rest of the Gulf.

For the forecast, the cold front will move southeast and is expected to extend from near Tampa, Florida to Tampico, Mexico Thu morning, from the Florida Straits to near Cabo Rojo, Mexico Thu night, Then exit the Gulf to the southeast by Fri morning. Scattered showers and thunderstorms will continue along and ahead of the cold front. Fresh to strong NE winds will follow in the wake of the cold front, with conditions improving Fri night through Sat. Fresh to strong return flow will set up in the northwestern Gulf Fri night and Sat. Looking ahead, the next cold front will emerge from the Texas coast Sat night and meander slowly southeastward across the northwestern Gulf Sun through Mon.

Caribbean Sea

Refer to the Monsoon Trough/ITCZ section above for convection in the Atlantic Basin. Fresh to strong with locally near-gale ENE winds and 10 to 12 ft seas are seen at the south-central and parts of the western basin. Moderate with locally fresh NE to ENE winds and seas at 4 to 6 ft are noted at the eastern basin. Gentle to moderate NNE to E winds and seas of 5 to 6 ft prevail for the rest of the basin.

For the forecast, the pressure gradient between the Bermuda High and lower pressure over northwestern Colombia will sustain fresh to strong trades across all but the northwestern basin through Thu morning, with locally near-gale winds and rough seas off Colombia. These winds seas should gradually diminish through Fri afternoon as the high shifts eastward. A new cold front will slowly enter the northwestern Caribbean on Fri, followed by fresh to strong NE winds. The front should stall from central Cuba to the southern Yucatan Peninsula by Sat morning, then gradually wash out over the northwestern Caribbean by Sat evening, with conditions improving during the remainder of the weekend.

Atlantic Ocean

A stationary front extends southwestward from 31N36W through 26N50W to 25N60W. Widely scattered showers are evident up to 40 nm along either side of the front. A surface trough near the east coast of Florida is causing scattered showers and isolated thunderstorms off southeastern Florida, including the northwest Bahamas. Convergent trades are causing widely scattered showers near the Windward Islands. Refer to the Monsoon Trough/ITCZ section at the very beginning for addition convection.

Moderate to fresh NE to E winds with 6 to 8 ft seas are found near and up to 150 nm north of the front, and also north of Puerto Rico and near the Turks and Caicos. Otherwise, gentle to moderate NE to SSE winds and seas at 4 to 6 ft dominate north of 20N between 35W and the Florida/southern Georgia coast, For the tropical Atlantic from 08N to 20N between 35W and the Lesser Antilles, gentle to moderate NE to ENE trades and 5 to 7 ft seas are evident. For the remainder of the Atlantic west of 35W, gentle with locally moderate SE to S winds and 4 to 6 ft seas prevail. For the forecast west of 55W, fresh NE winds along the front east of 65W will diminish through Thu morning, as the front dissipates. A 1030 mb Bermuda High to the north of the front will help to sustain fresh to strong ENE winds south of 23N and in the approach to the Windward Passage through tonight before diminishing on Thu. A new cold front will emerge off of the northeastern end Florida coast tonight, bringing with it fresh to locally strong N to NE winds behind the front. The cold front will extend from 31N72W to the Florida Straits Thu night, from 31N63W through the central Bahamas by Fri night, and then dissipate from 31N59W through the northwestern Bahamas by Sun morning. A tight pressure gradient in the wake of the front is forecast to bring increasing NE winds across much of the forecast area Sat, before gradually diminishing from west to east Sun.

Chan Posted about 1 hour ago by NHC Forecaster