000 AXNT20 KNHC 161658 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Dec 16 2021 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1655 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic from the border of Guinea- Bissau and Guinea near 11N15W to 09N18W. The ITCZ continues from 09N18W to 05N27W to 05N46W. Scattered moderate convection is noted from 01N to 06N east of 37W to the African coast. GULF OF MEXICO... Two surface troughs are analyzed over the Gulf of Mexico from 22N92W to 18N94W and 30N84W to 27N87W respectively. No significant convection is associated with these features as high pressure ridging dominates the Gulf of Mexico. Moderate to fresh winds prevail over the NW Gulf as well as the Florida Straits. Moderate winds are elsewhere. Seas are in the 2-3 ft range over the NE Gulf with 3-5 ft seas elsewhere. For the forecast, high pressure will prevail across the northern forecast waters through Sat, supporting moderate to locally fresh winds. A cold front is forecast to enter the basin Sat night into early Sun. Fresh to strong winds and building seas will prevail west of the front. CARIBBEAN SEA... An area of scattered moderate convection is observed on satellite imagery west of 80W between 09N and 19N. The pressure gradient between high pressure centered over the western Atlantic and lower pressure over Colombia is supporting fresh to strong trade winds over the central Caribbean, including the Windward Passage. Moderate to fresh winds prevail elsewhere. Seas are in the 8-9 ft over the central Caribbean, 6-8 ft over the eastern Caribbean, and 4-6 ft over the western Caribbean. For the forecast, strong high pressure will prevail over the western Atlantic through the forecast period. This will support fresh to strong trade-winds over the eastern and central Caribbean through the weekend. Moderate to fresh trades are expected elsewhere. ATLANTIC OCEAN... A surface trough is analyzed from 31N35W to 22N52W, which lies to the east of a cold front that extends from 31N45W to 25N53W to 31N68W. High pressure of 1033 mb is building in the wake of the front centered near 38N60W. Satellite derived winds reveal this area of high pressure is supporting strong to locally near- gale force behind the front and a large area of fresh to strong winds ahead of the front over much of the waters north of 13N between 50W and 70W. Another surface trough producing some cloudiness with possible embedded showers is analyzed from 30N74W to 27N73W. Moderate to fresh winds are noted west of 70W. Gales north of the area have generated a large northerly swell which has propagated into the northern waters. The swell is producing seas of 12 ft or greater north of 27N between 47W and 58W, and are currently peaking near 15 ft over the discussion waters. Seas of 7-8 ft are found between 52W and 75W in a mix of northerly swell. Elsewhere, gentle to moderate trade winds are east of 40W, with moderate to fresh winds between 40W and 60W. Seas over this area are in the 4-7 ft range. For the forecast,the area of high pressure will build southward, bringing an increase in winds and seas. $$ Nepaul