Tropical Waves

A central Atlantic tropical wave has its axis near 45W south of 12N. It is moving westward at 10 to 15 kt. Isolated showers and thunderstorms are within 60 nm east of the wave from the Equator to 01N and from 05N to 10N between 42W-45W.

A central Caribbean tropical wave has its axis near 73W south of 15N to inland South America. It is moving westward at 10 to 15 kt. No significant convection is noted.

Monsoon Trough Itcz

The monsoon trough axis enters the Atlantic through the coast of Mauritania near 18N16W, and continues southwestward to 07N25W, where it transitions to the ITCZ to 04N34W, where it briefly pauses. It resumes at 04N46W to the NE coast of Suriname near 04N51W. Scattered moderate convection is within 120 nm north of the ITCZ between 26W-29W and within 60 nm north of the ITCZ between 31W-34W.

Gulf Of America

The rather weak western extension of central Atlantic high pressure stretches westward across northern Florida and to north-central Gulf. The related weak pressure gradient is generally allowing for moderate to fresh SE winds along with moderate seas E of 90W, and for gentle to moderate southeast winds and slight seas W of 90W.

Divergence aloft attributed to a deep upper-level trough, and while abundant tropical moisture is being pulled northward from the Caribbean Sea is resulting in numerous showers and thunderstorms south of 27N between 83W-91W, including the northern Yucatan Peninsula, and the SE Gulf waters to along the coast of Cuba. Isolated showers and thunderstorms are elsewhere E of 91W.

For the forecast, the Atlantic ridge extending west- southwestward across Florida into the central Gulf will sustain gentle to moderate SE to S winds through the weekend. The exception will be evening pulses of fresh off the northern Yucatan through Thu night. An upper-level trough across the central Gulf should continue to couple with abundant tropical moisture to produce scattered heavy showers and strong thunderstorms over the central and eastern Gulf through Thu. These thunderstorms are capable of producing gusty winds, frequent lightning, reduced visibility, and locally rough seas. Mariners are urged to keep up to date with the latest forecast.

Caribbean Sea

The interaction between strong high pressure over the central Atlantic and relatively lower pressure to its south related to low pressure over northern S America has created a tight pressure gradient over the central part of the basin. This is inducing strong to near-gale trade winds along with rough seas across the central Caribbean. Moderate to fresh trade winds along with moderate seas are over the eastern Caribbean and Gulf of Honduras. Long-period E swell is creating rough seas in the Atlantic water passages of the Lesser Antilles. Elsewhere, moderate or lighter winds and moderate seas are prevalent.

The southeastern periphery of a well pronounced upper-level trough is supporting scattered showers and thunderstorms over the Yucatan Channel and waters adjacent to the northeast portion of the Yucatan Peninsula and the western tip of Cuba. Similar activity is inland over some sections of Cuba, and over the southwestern Caribbean S of 14N and W of 78W. This activity extends to inland Central America. Isolated showers are elsewhere N of 18N and W of Jamaica.

For the forecast, the tight pressure gradient in place over the central part of the basin will continue to support fresh to strong trades across the central Caribbean with rough seas through Fri. These winds are expected to pulse to near-gale force off Barranquilla, Colombia, during night-time and morning hours through Thu. Trades in the Gulf of Honduras will reach fresh to strong each evening through the same period. By Fri night, most of the basin should experience moderate with locally fresh winds and moderate seas, except the south- central basin in which fresh to strong winds and rough seas will remain through the weekend.

Atlantic Ocean

A weak cold front is analyzed from near 31N29W southwestward to 26N36W, where it transitions to a dissipating stationary frontal boundary to 24N45W, then extends northwestward to weak low pressure of 1023 mb at 26N55W and to 26N65W. Isolated showers are possible near this boundary. Moderate to locally fresh winds and seas of 6-9 ft are behind the frontal boundary. The remainder of the basin is under the influence of a broad and strong area of high pressure centered over the central Atlantic. The pressure gradient between the high pressure and relatively lower pressure in the deep tropics is sustaining fresh to strong E to SE winds and rough seas south and west of a line from 27N74W to 19N60W. Elsewhere, moderate to fresh easterly winds along with seas of about 6-8 ft are south of 20N and west of 30W, and moderate or weaker winds and moderate are over the remainder of the basin.

For the forecast west of 55W, fresh to strong winds along with moderate to rough seas are anticipated across waters south of 25N and west of 60W through Wed, including the Great Bahama Bank, as the Atlantic high pressure shifts southeastward, tightening the pressure gradient. As the high weakens Wed night, winds and seas will diminish from east to west.

Posted about 1 hour ago by NHC Forecaster Aguirre