000 AXNT20 KNHC 010000 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 700 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... ...GALE-FORCE WINDS IN THE GULF OF MEXICO... A cold front extends from NE Florida, into the N central Gulf of Mexico, to the coast of the Deep South of Texas. The cold front is forecast to move to a line from the Tampa Florida metropolitan area to the SW corner of the Gulf of Mexico at the end of 24 hours, and then to move through the Gulf of Mexico completely at the end of 48 hours. Surface high pressure is to the north of the front, in the central sections of the U.S.A. Hazardous marine conditions are going to be developing as the cold front traverses the Gulf of Mexico. Gusts to gale- force, within 60 nm of the coast and to the north of the front, between CHOCTAWHATCHEE BAY FL and BROWNSVILLE TX, are going to be part of the forecast for the next 24 hours. Expect gale-force N winds from 21N to 24N and W of 96W, with sea heights ranging from 9 feet to 14 feet, tomorrow morning, on New Year's Day. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough passes through the coastal areas of Liberia near 06N10W to 05N16W. The ITCZ continues from 05N16W to 03N30W, to the Equator along 48W, into NE Brazil near 01S52W. Precipitation: isolated moderate to locally strong rainshowers are from 02N to 06N from 50W eastward. rainshowers are possible also from 10N southward between 50W and 60W. ...DISCUSSION... ...THE GULF OF MEXICO... A cold front extends from NE Florida, into the N central Gulf of Mexico, to the coast of the Deep South of Texas. Precipitation: broken to overcast multilayered clouds and isolated moderate to locally strong rainshowers are within 60 nm to 90 nm on either side of 23N90W 27N86W 29N84W in the eastern half of the Gulf of Mexico. Other broken to overcast multilayered clouds and possible rainshowers are from 21N northward from 90W westward. Please read the SPECIAL FEATURES section for details about the cold front. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...THE CARIBBEAN SEA... An upper level ridge extends from the SE corner of the Caribbean Sea, to eastern Honduras, and to Belize/the southern part of the Yucatan Peninsula of Mexico. Scattered to broken low level clouds and isolated moderate rainshowers are from 70W eastward, from 16N to 20N between 70W and 80W including across Hispaniola, and from 14N to 20N from 80W westward. Widely scattered moderate to isolated strong rainshowers are in the SW corner of the Caribbean Sea, from 11N southward from 77W westward. Some of the precipitation is occurring over the waters and some is inland in Panama and in Costa Rica. This precipitation is to the north of the eastern Pacific Ocean surface trough. 24-hour rainfall totals in inches, for the period that ended at 31/1200 UTC, according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.09 in Guadeloupe, 0.05 in Curacao, and 0.02 in San Juan in Puerto Rico. ...HISPANIOLA... SURFACE OBSERVATIONS...Scattered to broken low level clouds and possible rainshowers are moving across the island. rainshowers are being reported in Santo Domingo. Few-to-scattered low level clouds, and broken high level clouds, are being observed elsewhere. The GFS MODEL forecast for 250 mb shows that SW wind flow will move across the island during the next 2 days. A ridge will extend from the SE corner of the Caribbean Sea to eastern Honduras. The position of the ridge is forecast to move comparatively more to the NE during the next 48 hours. The GFS MODEL forecast for 500 mb shows that anticyclonic wind flow will move across the area. An anticyclonic circulation center is forecast to be from 200 nm to 300 nm to the SE of Hispaniola during the next 2 days. The GFS MODEL forecast for 700 mb shows that day one will consist of E-to- SE wind flow across Hispaniola, with an Atlantic Ocean anticyclonic circulation center being about 300 nm to the NE of the island. Day two will consist of SW wind flow. A second and separate anticyclonic circulation center will develop in the southern coastal waters of Hispaniola. ...THE ATLANTIC OCEAN... Upper level cyclonic wind flow is to the north of the line that runs from South Florida, to 26N66W, beyond 32N46W. The first cold front passes through 32N55W to 29N60W. The front becomes stationary at 29N60W, and it continues to 28N66W, and 26N69W. The second frontal boundary is stationary at 32N66W, just to the west of Bermuda, to a 1015 mb low pressure center that is near 31N72W. A cold front continues from the 1015 mb low pressure center, to the northern half of the Bahamas. Precipitation: scattered moderate to isolated strong from 29N to 32N between 50W and 56W. Broken to overcast low level clouds and possible rainshowers are from 15N to 29N between 47W and 60W, and from 20N northward between 60W and 80W. A surface ridge passes through 32N30W, to 30N36W, 27N46W, 24N62W, and 23N70W. For additional information please visit http://www.hurricanes.gov/marine $$ MT