Tropical Waves

An eastern Atlantic tropical wave is along 27W, south of 15N, moving westward at 10-15 kt. Scattered moderate isolated strong convection is observed from 02N to 07. 5N between 22W and 33W.

A central Atlantic tropical wave is along 43W-44W, south of 17N, moving westward at 15 kt. Isolated moderate convection is near the wave axis.

Another Atlantic tropical wave is along 60W, south of 19N, moving westward at 15-20 kt. Scattered moderate isolated strong convection follows the wave from 06N to 09. 5N between 53W and 60W.

A Caribbean tropical wave is along 85W, south of 18N, moving westward at 10-15 kt. Scattered moderate to strong convection associated with this wave is along the monsoon trough in the SW Caribbean, while most associated convection is in the eastern North Pacific waters E of 88W.

Monsoon Trough Itcz

The monsoon trough enters the Atlantic through the coast of Guinea-Bissau near 12N16. 5W and continues southwestward to 04. 5N30W. The ITCZ extends from 04. 5N30W to 02. 5N42W and then continues from 02N44W to 01N50W. Scattered to numerous moderate to strong convection is along the W coast of Africa from 01. 5N to 11N E of 17W. Elsewhere, a few showers are seen near the ITCZ.

Gulf Of America

Widely scattered moderate convection is noted on satellite imagery across the western Gulf W of 95W, near the elongated area of low pressure along the Mexican coast, except for scattered moderate isolated strong convection S of 21N and W of 92. 5W. A tight pressure gradient between this low and a 1018 mb high in the eastern Gulf is sustaining fresh to locally strong SE winds and moderate to locally rough seas 6 to 9 ft west of a line from SW Louisiana to the NE Yucatan. Elsewhere, moderate or weaker anticyclonic winds and slight to moderate seas prevail.

For the forecast, an elongated area of low pressure has moved inland across coastal portions of eastern Mexico, but could re- emerge over the northwestern Gulf of America late Tue or Wed while interacting with a frontal boundary. The pressure gradient between the low pressure area and 1018 mb high pressure over the east- central Gulf will support fresh to strong SE winds and moderate to rough seas across the western Gulf through tonight, while scattered showers and thunderstorms continue there through Mon. The Atlantic ridge will build westward into the Gulf Tue through Thu, and combine with lower pressure over South Texas and northeastern Mexico will promote fresh to strong southerly winds over the western Gulf, and moderate to fresh winds over the eastern Gulf.

Caribbean Sea

A large cluster of moderate to strong convection persisting over the Cayman Islands and across the NW Caribbean waters between Jamaica and Cuba has begun to diminish recently, aided by middle to upper level troughing extending across the NW Bahamas and through the Florida Straits. Scattered moderate to strong convection has flared up along the monsoon trough across the SW Caribbean, behind the passing tropical wave. At the surface, the western Atlantic ridge extends through 26N55W westward across central Florida along 27N. The pressure gradient between this sub- tropical ridge and lower pressures in northern South America is forcing fresh to near gale easterly trade winds and rough seas over the central basin south of 198. Recent satellite scatterometer data captured winds up to 33 kt off northern Colombia, while satellite altimeter data showed seas in the area to near 12 ft. Elsewhere, moderate to fresh winds and moderate seas prevail across all but far NW portions.

For the forecast, the Atlantic ridge will generally remain in place through early Mon and support a large area of fresh to strong trade winds and moderate to rough seas across the central Caribbean. Expect highest winds and seas off the coast of Colombia. Pulsing winds to fresh to strong speeds are expected in the Gulf of Honduras nightly through Thu. The ridge will reorganize Mon through early Tue then shift slowly NE through Thu, leading to a slight decrease in wind and seas across the Caribbean basin.

Atlantic Ocean

Scattered showers and isolated thunderstorms are affecting the central and southeast Bahamas and central and eastern Cuba, but have diminished in intensity in recent hours. A broad ridge dominates the Atlantic basin along 26N-27N, and extends across central Florida. This pattern is supporting moderate to fresh easterly winds and moderate seas south of 22N and west of 35W, except for 7 to 8 ft seas just E of the Lesser Antilles. Fresh to strong NE winds and moderate to locally rough seas are found north of 15N and east of 30W. Elsewhere, moderate or weaker anticyclonic winds and slight to moderate seas prevail.

For the forecast west of 55W, the western Atlantic ridge will generally remain in place through early Mon, then reorganize along 60W Mon through early Tue, then shift slowly NE through Thu. This pattern will support moderate E to SE trade winds S of 22N, then become moderate to fresh through Wed. Gentle anticyclonic flow will prevail elsewhere through tonight then become gentle to moderate SE to S winds Mon through Wed. Fresh SW winds will develop across the NW waters N of 29N and W of 74W late Sun through early Mon, then expand eastward to 70W through early Wed, as a weak frontal system moves through the SE U. S. Expect fresh to strong winds each afternoon through late evening across Atlantic waters near Puerto Rico and Hispaniola.

Posted about 1 hour ago by NHC Forecaster Stripling