000 AXNT20 KNHC 132350 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 649 PM EST Tue Feb 13 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 2345 UTC. ...SPECIAL FEATURES... Caribbean Gale Warning: A tight gradient between a strong surface ridge over the N Atlantic Ocean and lower pressures in northern South America will continue to support gale-force winds near the coast of Colombia during the night time hours through the week. Seas associated with these gale conditions are forecast to be 14 to 18 ft, subsiding some later in the week. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...MONSOON TROUGH/ITCZ... The Monsoon Trough axis extends southwestward from the coast of Africa near 05N10W and crosses the equator near 19W. The ITCZ is located to the S of the equator. Scattered moderate isolated strong convection is within 120 nm S and 30 nm N of the axis between 10W-12W. Similar is well S of the axis within 30 nm of a line from 01N02W to 01N05W to 01N10W. ...DISCUSSION... GULF OF MEXICO... A cold front extends from the western Atlantic to inland NE Florida where it becomes stationary southwestward to 29N88W and a warm front from there to 27N94W to 26N96W S to 23N96W. It transitions back to a stationary front again to inland the coast of Mexico near Coatzacoalcos. A trough is ahead of the frontal boundary from 23N93W to inland Mexico just W of Nuevo Progreso, while another trough extends from just W of the front near 25N95W northwestward to just S of Corpus Christi, Texas. Isolated showers and thunderstorms moving northward are NW of the warm front between 90W-95W. Patches of rain and isolated thunderstorms are W of the stationary portion in the SW and far W central portions of the gulf. Isolated showers in very moist moderate to fresh E flow are over portions of the eastern gulf and Straits of Florida. High pressure W of the front is surging southward over the NW Gulf and across eastern Mexico. Strong northerly winds are S of 21N near the coast of Mexico. Moist southerly flow moving over the NE Gulf ahead of the front in response to a mid to upper level trough sliding eastward across the NE Gulf is producing widespread showers north of 25N east of the trough. The warm front will weaken as it slowly lifts northward as a warm front through early on Wed. CARIBBEAN SEA... Please refer to the SPECIAL FEATURES section above for details about the gale-force winds expected near the coast of Colombia. Satellite water vapor imagery shows dry and stable atmospheric conditions across the basin. Fast westward moving shallow trade wind showers, with gusty winds, are observed over much of the basin, except in the lee of Cuba and waters between Haiti and 76W and to the S of 13N between Colombia and 77W. The shower activity is more prevalent N of 12N and E of 71W to across the Lesser Antilles. Surface observations during the morning and early afternoon hours indicated strong wind gusts with these showers as they passed across the Leeward Islands and northern portion of the Windward Islands. The island of Dominica reported a wind gust to 34 kt at 16Z as a light shower went by. A strong ridge N of the area anchored by a 1033 mb high over the central Atlc near 32N53W extends across the northern half of the Caribbean, with the associated pressure gradient supporting fresh to strong trade winds east of 80W. Seas are 14 to 18 ft near Colombia and 8 to 12 ft elsewhere. Strong winds are also occurring through the Atlc passages, and are expected to continue through at least Wed. ATLANTIC OCEAN... Broad surface high pressure over the area is associated with a 1033 mb centered over the N central Atlantic near 32N53W and moving southwestward is supporting fresh to strong E-NE winds over most of the region, except close to the ridge axis N of 25N. Isolated showers, moving quickly westward, are noted from 13N to 18N and to the W of 52W, including over much of the Leeward Islands. This shower activity will move across the Leeward Islands through early this evening, and will be attended by strong gusty winds. Other isolated shower activity moving rapidly westward in moderate to fresh moist easterly flow are seen S of 26N and W of 57W. This activity is moving over the waters between the Bahamas and Cuba as well as across the Straits of Florida. A weak cold front along a position from 31N76W to inland NE Florida just S of Jacksonville, Florida as of 15Z will slowly sink southward to near 29N and westward to the vicinity of Daytona Beach by early this evening. The front is expected to become stationary across the central Atlantic Wed through Thu. Scattered showers and isolated thunderstorms along and within about 60 nm S of this frontal W of 77W will continue rather active through tonight as an upper level trough shifts eastward from the NE Gulf. The next cold front is forecast to move over the NW forecast waters by early on Sat morning. For additional information please visit http://www.hurricanes.gov/marine $$ JA/ERA