000 AXNT20 KNHC 181811 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sun Jan 17 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1750 UTC. ...SPECIAL FEATURES... Caribbean Gale Warning: High pressure building north of the area will continue to support strong to near gale force winds over the south-central Caribbean through the middle of the week. Overnight land breezes will allow these winds to pulse to gale force within 90 nm off the coast of Colombia, mainly between Cartagena and Barranquilla. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Sierra Leone to 18N13W. The ITCZ continues from 08N13W to 02N33W to the coast of Brazil near 00N48W. Scattered moderate convection is noted from 01N to 05N between 16W and 24W and between 28W and 35W. GULF OF MEXICO... A surface ridge extends from 1023 mb high pressure over the Northern Gulf near 29N90W extending through the Straits of Florida. Dry conditions prevail over the northwestern portion of the Gulf. To the east, a surface trough extends from Marco Island to 23N85W. Scattered showers are noted near the boundary. Scatterometer data indicated light to gentle anticyclonic winds across most of the basin, while moderate winds are noted near the Yucatan Peninsula. Buoy, ship and altimeter data also indicated 2 to 4 ft. High pressure over the northwest Gulf will shift eastward across the northern Gulf through Fri. Fresh to strong southerly return flow will set up over the NW Gulf tonight into Tue between the high pressure and lower pressure farther west over northeast Mexico. These winds will diminish some by Wed. A trough will form off the west coast of the Yucatan Peninsula each night through Wed night, supporting brief pulses of fresh to strong winds. CARIBBEAN SEA... There is a gale warning in effect for the south-central Caribbean. Please see the Special Features section above for more details. Moderate to fresh NE winds and 3 to 5 ft seas are noted over the northwest Caribbean. Gale force winds and 8 to 10 ft seas are noted off Colombia. Moderate to fresh trade winds are ongoing elsewhere across the southeast and south-central Caribbean, with 5 to 7 ft seas. Scattered showers are present from 14N to 19N between 79W-84W and in the Yucatan Channel. For the forecast, high pressure that will begin to build over the western Atlantic today will bring increasing winds and building seas over the southeast and south-central Caribbean, with winds pulsing to gale force off the coast of Colombia mainly at night through Tue. Fresh to strong northeast winds are also expected in the lee of eastern Cuba tonight through Wed night, diminishing to mainly fresh speeds Thu and to gentle to moderate speeds Fri. ATLANTIC OCEAN... West of 50W: A weakening cold front extends from near 31N51W to 27N60W where it then continues as a stationary front to 28N68W. Scattered showers are ongoing in broad swath from South Florida across the northern Bahamas to 31N76W. These showers are ahead of the cold front extending from a 1006 mb low near 37N67W to 29N72W to 26N80W. Moderate to fresh SE to E winds are evident ahead of this boundary over the waters north of 25N and west of 63W with 5 to 7 ft seas. West of the front, fresh to strong westerly flow is noted from the northern Bahamas to 31N between 73W to 81W. A 1022 mb high pressure is centered near 30N58W, supporting light to gentle breezes north of 25N between 27W and 54W. Seas are quite large in this area however, reaching 7 to 11 ft in lingering NW swell. Moderate trade winds persist south of 27N with 5 to 7 ft seas in open waters. For the forecast, the cold front will reach from near 31N72W to the NW Bahamas and to Miami this afternoon, then become stationary from near 26N65W to 22N71W and dissipating to eastern Cuba by early Tue. The boundary will gradually dissipate through early Thu. Another cold front will move southward into waters between northeastern Florida and Bermuda Wed night. The main portion of this front will lift to the northeast of the area Thu, leaving a trailing stationary segment to dissipate along 27N by late Thu. This will be followed by yet another front moving southward into the waters between Bermuda and NE Florida Fri. Farther east, the subtropical ridge supports gentle to moderate winds over the waters north of 22N, and moderate to fresh trades farther south. A large area of NW to N swell with significant wave heights reaching 8 to 13 ft are active north of 22N between 30W and 50W. Farther south, 6 to 8 ft seas prevail in a mix of N swell and shorter period easterly wind waves. $$ MTorres