000 AXNT20 KNHC 232322 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 622 PM EST FRI DEC 23 2016 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. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the coast of Liberia Africa near 06N10W to 05N15W. The ITCZ begins near 05N15W and continues along 02N34W to 04N52W. Scattered moderate convection is noted within 100 nm north of the ITCZ west of 25W. ...DISCUSSION... GULF OF MEXICO... A surface ridge is anchored over Virginia extending southwest reaching the Gulf providing a moderate anticyclonic flow across the basin. Over the southwest Gulf, a 1018 mb low is centered near 19N94W with an associated surface trough extending from the low to 24N97W. Shallow moisture over this region may support isolated showers in the vicinity of the low that is forecast to dissipate within the next 24 hours. Seas are ranging from 2-3 ft across the western half and 4-5 ft prevail across the eastern half of the basin. Mainly moderate return flow will dominate the basin through the middle of next week, except near the Straits of Florida where fresh to strong easterlies will continue through Monday night as the pressure gradient tightens across the area. Seas will build up to 8 ft as a result. CARIBBEAN SEA... Water vapor imagery depicts strong dry air subsidence across the basin supporting fair weather. A tight pressure gradient across the north central Caribbean supports fresh to strong northeast winds through the Windward Passage, in the lee of central Cuba, and in the lee of the Dominican Republic. Elsewhere, moderate to locally fresh trades prevail. Seas are measured at 4 to 7 ft across the area as well, except up to 8 ft near the Windward Passage and in the lee of the Dominican Republic. The hotspots of stronger winds will persist through the upcoming weekend, expanding in coverage to across most of the basin by the end of the weekend through early next week as high pressure builds north of the area. Seas will build to 6 to 10 ft by early next week as the stronger winds increase in areal extent. ...HISPANIOLA... Fair weather prevails across the island at this time. Showers are expected to develop through the weekend as an upper-level trough stalls over the island. ATLANTIC OCEAN... A middle to upper-level trough over the west Atlantic supports a cold front from 31N69W to 28N77W. A pre-frontal trough extends from 30N63W to 26N76W. Isolated showers are in the vicinity of these two features. A second surface trough extends from 31N57W to 26N64W with scattered moderate convection. Surface ridging anchored northeast of the Azores extends across the remainder Atlantic forecast waters. A surface trough extends over the far east Atlantic from 29N20W to 21N20W with isolated showers between 17W-22W. High pressure will build in across the basin from the north during the weekend. This high will slide to the east through the weekend with fresh to strong winds becoming confined to the waters south of 25N through the day Saturday, then to across the waters south of 27N Sunday into Monday as a new high pressure builds in from the Carolinas. For additional information please visit http://www.hurricanes.gov/marine $$ ERA