000 AXNT20 KNHC 311701 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1200 PM EST Sun Dec 31 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 1615 UTC. ...SPECIAL FEATURES... An middle to upper level trough is noted on water vapor imagery over NW Mexico and the Gulf of California that is expected to merge with northern stream energy currently moving southward central Great Plains and drive a cold front southward across the Gulf basin Sunday night through Monday. While fresh to strong northerly winds will follow the cold front...near gale to gale force N-NW winds are expected generally S of 24N W of 94W Monday through early Tuesday. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 06N10W to 05N16W. The Intertropical Convergence Zone axis extends from 05N16W to 04N25W to the Equator near 51W. Scattered moderate convection is from 02N-06N between 36W-50W...and from 03N-10N between 50W-59W. ...DISCUSSION... GULF OF MEXICO... A cold front extends across the northern Florida peninsula from near Cape Canaveral to 29N84W then becomes stationary into a 1017 mb low centered along the Louisiana coast near 29N91W. A cold front then extends W-SW from the low center to the Texas coast near Corpus Christi. The low is expected to slowly drift eastward through Sunday night and remain embedded within the Special Features cold front. Through Sunday night...the front will become invigorated by the middle to upper level dynamics mentioned above as middle to upper level energy over the central Great Plains phases with a middle to upper level trough over NW Mexico. Fresh to strong northerly winds are expected to follow in wake of the front and cover much of the basin by Monday night as the front moves SE of the basin by Tuesday. Currently...widely scattered showers and isolated tstms are occurring N of 25N between 85W-90W with isolated showers possible elsewhere within 90 nm either side of the cold front W of 90W. CARIBBEAN SEA... South-southwesterly flow aloft prevails over the Caribbean basin this afternoon on the western periphery of an upper level ridge axis extends from over the southern Windward Islands to over Nicaragua and Honduras. Otherwise...conditions at the surface remain relatively tranquil with moderate to occasional fresh trades expected to persist through Wednesday. By Monday night however...a cold front sweeping across the Gulf of Mexico will begin to impact the NW Caribbean with moderate to fresh N-NE winds. The front will gradually weaken through Wednesday and a reinforcing front will increase northerly winds again Wednesday night into Thursday generally W of 75W. ...HISPANIOLA... Mostly dry and stable conditions aloft are noted on water vapor imagery...with patches of shallow moisture and possible isolated showers embedded within moderate trade wind flow. Little change is expected the next couple of days as low level moisture continues to advect westward across the region. ATLANTIC OCEAN... Broad longwave middle to upper level troughing is noted on water vapor imagery over the western North Atlc supporting a pair of cold fronts that enter into the SW North Atlc discussion area this afternoon. The primary cold front extends from a 997 mb low centered SE of Nova Scotia near 42N55W SW to 32N70W to the Florida peninsula near Cape Canaveral. A weak 1016 mb low is centered in the vicinity of the front near 30N74W with a surface trough extending S-SW across the central Bahamas to 24N80W. Isolated showers are possible within 90 nm either side of the cold front between 65W-76W. To the east...the other cold front extends from 32N57W SW to 26N70W. Low-level moisture convergence is maximized generally in the vicinity of 29N55W E of the front and along with ample mid-level lifting dynamics...scattered showers and isolated tstms are occurring N of 27N between 45W-60W. The remainder of the eastern Atlc is under the influence of a surface ridge anchored by a 1034 mb high centered SE of the Azores near 37N24W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN