Monsoon Trough Itcz

The monsoon trough enters the Atlantic through the coast of Guinea-Bissau near 12N16W and continues southwestward to 03N21W. The ITCZ extends from 03N21W to 01S35W and to 00N50W. Scattered moderate to isolated strong convection is within 120 nm north of the ITCZ between 23W-26. 5W, also within 120 nm south of the ITCZ between 29W-31W, within 60 nm north of the ITCZ between 38. 5W-41. 5W and within 60 nm south of the ITCZ between 46W-48W. Similar activity is just west of the ITCZ from 01S to 02N between 50W-52W.

Gulf Of America

High pressure of 1020 mb centered over the NE Gulf at 29N85W basically dominates the weather pattern across the area, providing for light to gentle winds in the basin, except for gentle to moderate north to northeast winds in the eastern Gulf south of 29N and east of 85W. Seas over the Gulf are in the range of 2 to 3 ft west of 89W and 3 to 4 ft east of 89W as seen in overnight altimeter satellite data passes and as recorded in the latest buoy observations.

For the forecast, high pressure is building across the area in the wake of the recent cold front maintaining rather tranquil conditions. The high pressure will slide eastward through Wed night in response to a deepening low pressure system in the upper U. S. Midwest region that will be moving eastward. As this happens, the pressure gradient will tighten over the western half of the Gulf leading to moderate to fresh return southerly flow over those waters. These winds will expand to the western part of E Gulf Thu through late Fri. The low pressure will pull a cold front into the NW Gulf on Sat and Sat night, followed by fresh to strong northerly winds expected behind it Sat night.

Caribbean Sea

A trough extends from central Cuba near 21N78. 5W to 18N83W. Isolated showers and thunderstorms are seen from 20N to 21N between the trough and 81W. Isolated showers are possible elsewhere near the trough. High pressure across the central Atlantic is controlling the trade wnd regime throughout. The associated gradient is allowing for fresh to strong trades to exist in the south-central sections of the basin, including offshore near the coast of Colombia, where an overnight scatterometer satellite data pass confirmed the presence of these winds. Seas with these winds are in the range of 6 to 9 ft. Overnight scatterometer satellite data passes indicate that moderate to locally fresh trades are elsewhere south of about 17N and east of 81W while light to gentle trades are north of 17N and east of 81W, and light to gentle north to northeast winds are west of 81W. Seas elsewhere across the basin are in the range of 3 to 5 ft, except for higher seas of 6 to 9 ft in northeast swell south of 11N between the coast of Colombia and 80W. Lower seas of 3 to 4 ft are north of 18N and west of 76W. Seas of 2 to 3 ft are near the Windward Passage.

For the forecast, pulsing fresh to strong northeast to east winds will continue offshore Colombia through the forecast period. These winds are expected to expand in coverage starting late on Thu, with the possibly of near gale-force speeds Fri and Sat night as Atlantic ridging noses westward tightening the pressure gradient. Fresh northeast winds will develop in the Windward Passage and in the lee side of Cuba today through Wed evening. Fresh to strong east to southeast winds will begin to pulse in the Gulf of Honduras Wed evening and continue through the rest of the forecast period, and trades elsewhere will generally remain at moderate to fresh during this same time.

Atlantic Ocean

A cold front has recently passed Bermuda, where northwest winds are gusting to 30 kt. It is analyzed from near 31N66W southwestward to 26N70W and to the coast of central Cuba at 22N78W. Fresh to strong south to southwest winds are ahead of the front to near 56W and north of 27N as depicted in overnight scatterometer satellite data passes. Seas with these winds are in the range of 7 to 10 ft. Mostly fresh north to northeast winds are behind the front north of about 27N along with seas of 7 to 10 ft in a long-period north to northeast swell. A trough is out ahead of the front from 28N66W to 22. 5N70W. In addition, a deep layer trough is shifting eastward between 57W and 73W. Latest satellite imagery shows very active convection in the form of scattered to numerous showers and thunderstorms over the waters generally north of about 22N between 55W and the front/trough. This activity may be accompanied by strong gusty winds as it translates in a general eastward motion.

A broad subtropical ridge dominates the rest of the tropical Atlantic, sustaining moderate to fresh easterly trade winds and moderate to rough seas south of about 20N and west of 25W. Elsewhere, moderate or weaker winds and moderate seas are prevalent.

For the forecast west of 55W, the aforementioned cold front will reach from near 31N59W to 26N66W and to the southeastern Bahamas this afternoon. It will cross 55W tonight into early Wed. Fresh to strong south to southwest winds ahead of the front N of 28N will diminish to fresh speeds as the front crosses 55W. Fresh to strong north to northeast winds behind the front will become north to northeast fresh winds this morning. Elsewhere, long-period northerly swell will continue to support rough seas over the waters E and NE of the Bahamas through Thu night. Looking ahead, fresh southwest winds are expected to develop over the far NW part of the area beginning Sat ahead of an approaching cold front, and as a high pressure ridge noses westward toward Florida roughly along 26N. Active convection is over a good portion of the eastern half of the offshore zones N of 22N due to an upper-level trough in the area, the approaching cold front and a surface trough, remnants of an old frontal boundary, that extends from 23N55W to 23N60W and to near 22N65W. Mariners are urged to stay up to date with the latest forecasts.

Posted about 2 hours ago by NHC Forecaster Aguirre