000 AXNT20 KNHC 211051 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 551 AM EST Thu Dec 21 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 0600 UTC surface analysis and satellite imagery through 1045 UTC. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean from 07N12W to 04N24W. The ITCZ extends from 04N24W to 01N41W. Scattered moderate convection is from 00N-07N mainly west of 20W. ...DISCUSSION... ...GULF OF MEXICO... A warm front extends along the coasts of Texas to southern Louisiana near 30N89W. A cold front continues from that point then extending over the Florida Panhandle and into the west Atlantic. A surface ridge along 22N extends across the remainder of the basin anchored by a 1019 mb high centered in the west Atlantic over the northern Bahamas. Light to gentle winds dominate the basin, except north of 29N and east of 90W where moderate to fresh west winds are noted in scatterometer data. The cold front over the northeastern Gulf will move south while weakening and becoming stationary over central Florida. The next cold front is forecast to come off the coast of Texas early Saturday morning, extending from the Florida Big Bend to Tampico, Mexico by early Sunday and from south Florida to Veracruz, Mexico on Monday morning. Fresh to near-gale force northerly winds will follow the front starting on Saturday. ...CARIBBEAN SEA... Broad mid to upper level ridging dominates the Caribbean waters along with very dry air aloft supporting fair weather. A surface ridge anchored over the west Atlantic continues to tighten the pressure gradient over the central Caribbean, thus resulting in fresh to strong winds between 71W and 80W and strong to near gale-force winds along the coast of Colombia. Little change is expected in the upper-to mid-level weather pattern through Friday. ...HISPANIOLA... As previously discussed, broad mid to upper-level anticyclonic wind flow and dry upper to mid-level air dominate the entire Caribbean Sea supporting mostly stable conditions. However, low- topped trade wind showers are forecast to move over the island on Friday and Saturday evenings. ...ATLANTIC OCEAN... A pair of surface troughs extend across the central portion of the basin. The first was analyzed from 31N52W to 27N62W with isolated showers. The second one is from 30N41W to 24N54W. Scattered moderate convection prevails along the northern portion of this trough between 38W-44W. The remainder of the basin is under the influence of surface ridges, anchored by a pair of 1019 mb highs centered near 25N77W and 26N65W, and a 1038 mb high near 42N17W. A cold front associated with a surface low currently off the coast of South Carolina, will enter the western Atlantic waters by this morning and race southeast through Friday night. A stronger cold front will enter this same region on Sunday night. For additional information please visit http://www.hurricanes.gov/marine $$ ERA