000 AXNT20 KNHC 171717 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1217 PM EST Sun Dec 17 2017 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 1715 UTC. ...SPECIAL FEATURES... ...Caribbean Sea Gale Warning... Strong surface high pressure centered off the coast of South Carolina and the west Atlantic tightens the pressure gradient in the south- central Caribbean, thus supporting gale-force winds along the northwest portion of the Colombian coast. These winds will pulse every night through early next week as the ridge builds over southwest Atlantic waters. Sea heights will range from 8 to 15 feet in the area of strongest winds. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough passes through the coast of West Africa near 07N12W to 06N26W. The ITCZ continues from 06N26W to 07N45W. No significant convection is observed along these boundaries at this time. ...DISCUSSION... GULF OF MEXICO... A mid level short-wave trough extending from northern Texas to a base over the northwest Gulf waters supports a 1015 mb low centered over southwest Louisiana. A cold front extends from the low to near Tampico, Mexico while a warm front extends from the low to the east to 31N87W to 29N84W. Scattered moderate convection is observed north of 28N between 90W-93W. Fresh to strong winds are in the vicinity of the low due to a tight pressure gradient between the low and high pressure over the southeast CONUS. The front will weaken gradually today and transition into a surface trough as the low moves inland over through early Monday. CARIBBEAN SEA... Gale-force winds will continue to pulse at night in the south- central Caribbean as a strong high pressure builds in the west Atlantic waters. Please refer to the Special Features section above for details. Fair weather prevails across the remainder of the basin supported by a broad mid to upper-level high and very dry air aloft. Little change is expected through the next 24-48 hours. ...HISPANIOLA... A broad mid to upper-level high is covering the Caribbean and very dry air aloft support stable conditions across the island. Similar conditions are forecast through Monday. Fresh to strong easterly winds will continue across the Windward Passage through mid-week. ATLANTIC OCEAN... A broad mid to upper-level trough over the west Atlantic supports a frontal system, analyzed as a cold front from 31N50W to 25N63W, then as a stationary front from that point to 24N79W. No significant convection is associated with these frontal boundaries. Strong high pressure is building west of the fronts and is forecast to prevail over the area through the mid-week. To the east, the Azores high continues to extend across the eastern Atlantic waters with fair weather. For additional information please visit http://www.hurricanes.gov/marine $$ ERA