Special Feature

West Atlantic Significant Swell: Strong high pressure over s the NW Atlantic extends a ridge southwestward and across the local western Atlantic waters, to the north of a stalled cold front lingering from near Bermuda through the central Bahamas. A very tight pressure gradient north of this front is producing a long and sustained fetch of strong northeast winds that is generating very rough seas in the Atlantic waters north of the front. Overnight SoFar Ocean buoys and recent altimeter data show a large area of 11 to 15 ft seas persisting north of the front to 31N, and extending westward to just offshore of the east coast of Florida. Strong northeast winds and very rough seas will prevail for the next few hours before winds gradually diminish late tonight, as the front weakens. Large northeast swell at 12-13 seconds will maintain rough seas between Bermuda and the Bahamas into the start of next week, but are expected to subside below 12 ft this morning. Fresh to strong winds are forecast to return Sat night into early next week as the pressure gradient tightens again.

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 on both areas of significant swell.

Monsoon Trough Itcz

The monsoon trough axis enters the Atlantic along the coast of Guinea near 10. 5N14. 5W and extends southwestward to 03. 5N20W, where it transitions to the ITCZ and continues to NE Brazil near 01. 5S46W. Scattered moderate to isolated strong convection is within 180 nm south of the ITCZ between 19W and 24W. Scattered moderate convection is within 60 nm north of the trough between 16W-20. 5N

Gulf Of America

Broad ridging extends from the eastern U. S southwestward to across the Gulf region. A lingering frontal boundary is weakening from the central Bahamas to along the NW coast of Cuba. The associated pressure gradient north of this boundary is leading to fresh to strong northeast to east winds across the eastern and north- central Gulf along with seas of 6 to 8 ft. Elsewhere, northeast to east winds are moderate or weaker, with seas 3 to 5 ft, except for higher seas of 5 to 7 ft north of 23N.

A mid-level disturbance moving across South Texas as seen in water vapor imagery is triggering off a large area of light to moderate rain, with embedded scattered showers and isolated thunderstorms over the interior of South Texas. This activity also extends into northeastern Mexico, and east from there to the offshore waters near 96W from 25N to 26N. This activity may hold together as it generally moves eastward across the western Gulf through this afternoon.

For the forecast, strong high pressure over the eastern U. S. will support strong northeast winds and rough seas across the northeast Gulf through early this morning. Moderate to fresh east to southeast winds and moderate seas elsewhere across basin will change little through the middle of next week, except for occasional strong east winds off western Cuba and off the northwest Yucatan. Locally rough seas will continue in the Straits of Florida into early next week.

Caribbean Sea

A weaker pressure gradient over the area is allowing for fresh to strong trades to be confined to the south-central portion of the basin, south of about 15N. Seas with these winds are in the range of 6 to 9 ft. Elsewhere across the Caribbean winds are moderate or weaker along with seas of 3 to 5 ft, except for 1 to 3 ft seas in the northwestern section of the basin.

Shallow moisture in the form of scattered to broken low clouds embedded in the trade wind flow is moving across the Lesser Antilles and into the eastern basin. Brief passing showers are possible within this area of moisture.

For the forecast, strong high pressure building southward from the western Atlantic will tighten the pressure gradient and increase winds over the basin, leading to strong winds over the south- central Caribbean through the weekend and into early next week. Fresh to strong northeast winds and building seas will commence south of Cuba, in the Windward Passage, and south of Hispaniola starting Sat night.

Atlantic Ocean

Please see the Special Features section above for information on western Atlantic significant swell offshore Florida.

A cold front extends from a 1015 mb low near 32N66W southwestward to 30N67W, where it becomes a nearly stationary front to near 23N75W. Strong high pressure is building southward north of the front. A surface trough is analyzed out ahead of the frontal boundary from near 31N64W to 27N69W and to 24N73W. Meanwhile, an upper shortwave trough shifting eastward is noted on water vapor imagery just east of surface trough, and is helping to sustain scattered moderate convection north of 26N between 60W and 65W, and from 23N to 25N between 65W and 71W. Similar activity is seen within 60 nm east of the cold front. Overnight scatterometer satellite data indicates fresh to strong northeast winds and rough to very rough seas of 11 to 15 ft north the front, while gentle to moderate winds and rough seas in long-period north swell are up to around 240 nm ahead of the front. Elsewhere, a strong 1034 mb Azores High is centered north of the discussion area near 35N37W, with a ridge stretching southwestward to near 21N62W. Broad anticyclonic flow related to this feature covers the area north of about 15N and between Africa and 64W. The large pressure gradient between the high pressure and relatively lower pressure in the vicinity of the ITCZ is supporting fresh to strong trades from 10N to 26N and east of 50W. Seas are 8 to 12 ft east of 52W, and 5 to 8 ft east of the front to 52W. Moderate to fresh trades are south of 13N along with seas of 7 to 10 ft in long-period north to northeast swell.

For the forecast west of 55W, the pressure difference between the aforementioned frontal boundary and the strong high pressure to its north will maintain mostly strong northeast winds for a few more hours before they diminish to mostly fresh speeds. Rough seas from large northeast swell will linger into this afternoon and into the start of next week between Bermuda and the Bahamas. Fresh to strong northeast winds are likely to return Sat night into early next week as the pressure gradient tightens.

$$ Aguirre Posted about 1 hour ago by NHC Forecaster