000 AXNT20 KNHC 272337 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 637 PM EST Tue Feb 27 2018 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... A strong 973 mb low pressure system with storm force winds centered over the Azores supports a cold front that crosses the Madeira and the western Canary Islands from 32N17W to 25N24W to 20N46W then continues as stationary front to 25N53W. A tight pressure gradient associated with the deep low pressure and cold air advection associated with cold front are supporting gale force winds N of 29N and west of the front to 38W. Gale conditions are forecast to prevail through tonight then will gradually diminish as the low pressure weakens and moves E and the front dissipates. Altimeter satellite passes are showing seas of 15 to 30 ft in NW to N swell north of 20N and east of 45W. For more details, refer to the NHC High Seas Forecast under AWIPS/WMO Headers MIAHSFAT2/FZNT02 KNHC. Gale force winds are also observed per scatterometer data ahead of the front over the Madeira and the Canary Islands. Meteo France is including a forecast of gale force winds in the areas called Irving, Madeira, and Casablanca, Agadir. The forecast calls for SW to W gale force winds with severe gusts. Please refer to the Meteo- France High Seas Forecast for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the eastern Atlantic from the coast of Liberia near 06N11W to 02N16W, where it transitions to the intertropical convergence zone which continues to 00N20W to 01N30W to 04N36W to the coast of Brazil near 02S44W. Scattered moderate and isolated strong convection is present from 05S to 02S between 17W and 24W and from 04S to 03N between 24W and 30W. ...DISCUSSION... GULF OF MEXICO... A weakening frontal boundary reaches from near Tampa Florida to the Coastal Bend of Texas. Radar and satellite imagery from the across the northern Gulf shows limited cloudiness and only a few spotty showers along and up to 90 nm north of the frontal boundary. Otherwise, weak ridging extends WSW from the Straits of Florida over the central Gulf. Light to moderate east to southeast winds are generally noted over the Gulf with 2 to 4 ft seas prevailing. For the forecast, the front will weaken and dissipate today and tonight. High pressure already over the region will be strong enough to suppress convection today through Wed night. Another, stronger cold front will move into the NW Gulf Wed night. Gale conditions will be possible over the SW Gulf near Tampico Thu night and near Veracruz Fri morning following the passage of this front. CARIBBEAN SEA... Weak high pressure centered approximately between Bermuda and the northern Bahamas near 27N71W is supporting moderate to fresh to trade winds over the basin, except for over the south central Caribbean and to the lee of Cuba. Moderate to fresh trade winds persist elsewhere. An upper-level low is centered NE of Puerto Rico near 23N63W. A sharp trough extends SW from the low to Costa Rica. This trough is triggering a few showers over Hispaniola and over portions of the northeast Caribbean. Otherwise, convergent upper- level winds on the NW side of the trough are suppressing convection over the western half of the Caribbean. Little change is expected during the next several days as moderate to fresh winds persist over the basin. Strong winds will continue pulsing along the N coast of Colombia during the late night and early morning hours. Strong winds will also funnel through the Windward Passage through Thu. Large long period swells will reach the Atlantic passages in the Leeward and Windward Islands on Thu. ATLANTIC OCEAN... A weak pressure gradient resides over the Atlantic waters west of 45W. Gentle to light winds north of 22N and moderate trade winds south of 22N are generated by modest 1022 mb high pressure centered near 26N71W. A weakening cold front crosses the waters NW of the Bahamas from 32N68W to near Cape Canaveral Florida. Cloudiness and scattered showers are occurring along and up to 90 nm SE of this boundary. Looking ahead, the cold front will weaken and continue heading SE to reach the central Bahamas Wed evening, as high pressure builds north of the front. Strong low pres passing north of the area will drag another cold front into the NW waters Thu night, with deteriorating conditions expected for the waters north of 27N and W of 65W. The system will support gales Fri night through Sat night over the waters N of 27N between 50W and 70W. A significant swell event will accompany this system, affecting all waters east of north Florida and Bahamas at the end of the week. East of 50W, fresh to strong northwest winds extend outward from the areas of strong to gale force winds noted in the Special Features sections to as far S as 20N and as far W as 45W. Because the subtropical ridge is disrupted by the deep low pressure over the north central Atlantic, only gentle to moderate trade winds are currently occurring over the Tropical Atlc waters E of the Windward Islands. Long period NW to N swell generated by the deep low near the Azores are causing seas of 8 to 12 ft to reach as far south as 15N to the E of 40W. Looking ahead for the waters east of 50W, winds and seas will gradually subside north of 25N through mid week, then another powerful low pressure system is expected to approach from the western Atlantic and bring strong to near gale force winds and large seas to the area north of 20N between 40W and 50W once again by then end of the week. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy