339 AXNT20 KNHC 060436 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Mon Mar 06 2023 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 0000 UTC surface analysis and satellite imagery through 0420 UTC. ...SPECIAL FEATURES... Atlantic Significant Swell Event: long-period NW swell is currently propagating through the central and eastern waters generating seas in the range of 12-16 ft north of 26N and between 30W-60W with a period of 12-14 seconds. This batch of swell will shift east and subside just as another set of long- period NW swell begins to propagate through the central Atlantic Mon night through Tue. This second set will bring seas of 12-16 ft north of 25N, between 35W and 60W. Late Tuesday, a third set of NW swell will follow a cold front. Seas to 20 ft are expected in the central Atlantic north of 30N by Wed while moderate period swell in excess of 12 ft will propagate as far south as 21N by Thu, impacting waters east of the Bahamas to the central Atlantic. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details on these swell events. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Liberia near 06N10W to 05N12W. The ITCZ continues from 05N12W to 03S40W. Scattered moderate convection is observed within 240 nm of the ITCZ. ...GULF OF MEXICO... A weak surface trough extends across the central Gulf of Mexico from 27N89W to 24N93W. Weak high pressure dominates the remainder of the basin. No significant convection is observed and winds are generally light to gentle from the east. Seas remain in the 2-4 ft range. For the forecast, weak high pressure will dominate the area early this week, before shifting away, allowing a weak cold front to enter the NE Gulf Wed. ...CARIBBEAN SEA... The gradient between high pressure in the SW North Atlantic and lower pressure over Colombia is supporting fresh to strong E-NE winds in the south-central Caribbean. Seas are 7-9 ft in the Colombian Basin as a result of these winds. Winds are generally moderate from the E across the remainder of the basin with 5-7 ft seas, except in the NW Caribbean, where winds are gentle and seas are slight. For the forecast, the pressure gradient between a high pressure ridge extending from the NW Bahamas to 21N50W and the Colombian diurnal low will support strong trades across the south-central Caribbean tonight. Winds will gradually diminish to below normal basin-wide Tue through Thu as an Atlantic cold front sinks southward toward the NE Caribbean islands. ...ATLANTIC OCEAN... Please read the Special Features section for details on significant swell events impacting the Atlantic forecast waters this week. A cold front extends from 31N51W to 28N73W. A few showers and thunderstorms are observed within 60 nm of the frontal boundary. North of the front, winds are strong from the N-NW with 12-16 ft seas. South of the front, winds are fresh from the W with 10-14 ft seas. A high-pressure ridge extends across the basin between 20-25N. Winds are light within the ridge axis, although swell associated with storms north of the area is continuing to propagate through these latitudes in the central Atlantic. In the eastern Atlantic, a weak cold front extends from 31N27W to 26N36W. Winds are mainly gentle to moderate near the front, though a recent altimeter pass found seas of 12-15 ft embedded in large NW swell. South of the front, a 1019 mb high centered near 25N25W dominates the pattern with gentle anticyclonic flow and moderate seas. For the forecast west of 55W, surface ridging extends from 21N50W to the NW Bahamas. A cold front that currently extends from 30N55W to 27.5N73W will move SE through Mon, bringing fresh to strong SW ahead of it through tonight, N of 27N and E of 58W. The ridge will weaken and reform NE of the Bahamas into Tue as the front dissipates along 25N. Large NW swell will impact the NE waters behind the front tonight through Tue night, then large N to NE swell will move south of 31N and spread across all Atlantic waters into Thu night with the next frontal system approaching from the north. Gale conditions are possible Tue night through Wed morning, north of 27N and east of 67W on both sides of this next front. The front will extend from 31N65W to 29N73W late Tue night, and reach from 31N55W to 25N73W by early Wed. Seas will reach over 20 ft on Wed north of 30N and east of 62W. $$ Flynn