000 AXNT20 KNHC 100604 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 104 AM EST SAT DEC 10 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... ...Gulf of Mexico Gale Warning... A strong ridge is across the Gulf of Mexico and inland Mexico where is anchored by a 1032 mb high near 21N98W. The ridge builds behind a cold front that currently extends across the Straits of Florida to northwest Cuba near 22N84W to 22N987W where it stalls and continues to the SW Gulf along 22N91W to a 1018 mb low near 21N92W to 19N92W. A very strong pressure gradient between the ridge and the front is producing a large area of minimal to strong NW gale force winds from 18N to 21N between 94W and 96W. This is generating a large area of high seas 16 to 21 ft. A 1036 mb high pressure center over Arkansas also anchors the ridge, and is forecast to shift eastward during the next 24 hours. As this occurs the front will sink slightly southward, and the pressure gradient will gradually decrease across the NW Gulf. However, gale force NW winds are expected to continue through Saturday evening offshore of Veracruz, Mexico. Please read the High Seas Forecast product under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across the African Continent reaching the Atlantic Ocean near 10N18W. The ITCZ begins near 05N20W and continue along 03N38W to 02N50W. A surface trough extends from 5N-10N along 33W and another from 05N-09N along 45W. Active convection continues along the ITCZ, where scattered moderate to strong is observed from 02N-08N between 13W and 36W. ...DISCUSSION... GULF OF MEXICO... The main concern for the Gulf continue to be a gale warning over the SW basin. A strong ridge across the Gulf of Mexico builds behind a cold front that extends across the Straits of Florida to NW Cuba near 22N84W to 22N987W where it stalls and continues to the SW Gulf along 22N91W to a 1018 mb low near 21N92W to 19N92W. A very strong pressure gradient between the ridge and the front is producing a large area of minimal to strong NW gale force winds from 18N to 21N between 94W and 96W. This is generating a large area of high seas 16 to 21 ft. Gale force NW winds are expected to continue through Saturday evening. Please refer to special features for further details. Broken to overcast cloudiness along with scattered to isolated showers are S of 28N E of 90W and in the SW Gulf S of 22N. Fresh to near gale force north-northeast winds are across the eastern Gulf waters S of 28N. The front is expected to meander across the southern Straits of Florida and northwest Cuba this weekend with northerly winds slowly diminishing below gale force late Sat in the western Gulf. CARIBBEAN SEA... A broad upper ridge prevails over the basin with strong dry air subsidence supporting fair weather over the NW Caribbean. Over the central basin, a surface trough supported by a middle level inverted trough extends from 16N73W to 10N72W. This surface trough is under a upper level diffluent environment that supports scattered showers S of Hispaniola between 66W and 75W. In the SW Caribbean, the monsoon trough crossing Costa Rica all the way to N Colombia support scattered heavy showers S of 12N W of 79W. Fresh to locally strong NE to E winds are occurring S of 16N between 69W and 80W. The trough will continue west across the basin and enter Central America early Sun. Moderate to fresh NE trades prevail across the remainder of the basin, except fresh NE winds in the Yucatan Channel near an approaching cold front. Fresh to occasional strong trades are expected across the south-central Caribbean mainly north of Colombia tonight through late Saturday with trades increasing slightly through the remainder of the weekend as the strong ridge affecting the Gulf of Mexico shifts eastward into the western Atlantic. The cold front will meander across the Yucatan Channel, with associated conditions across the Gulf spreading modestly into NW portions. ...HISPANIOLA... Fair weather prevails across the island due to strong subsidence of dry air. A modest increase in low level moisture will spread westward across the area tonight and should lead to passing tradewind showers across the area. Generally fair conditions are expected through the weekend. ATLANTIC OCEAN... A cold front extends across the western Atlantic from 31N63W through the NW Bahamas to northwestern Cuba. Broken to overcast cloudiness and isolated showers observed west of the front. Ahead of this front, a dissipating stationary front extends from 28N50W to 26N68W to the central Bahamas to northern Cuba, which will be overtaken by the cold front within the next 24 hours. The remainder of the basin, is dominated by a surface ridge anchored by a 1025 mb high centered near 36N29W. Expect the cold front in the west Atlantic to continue moving east of the Bahamas while it drifts slightly SE across the Bahamas. As the surface ridge behind this cold front begins to shift eastward into the Atlantic overnight and Sat, look for increasing NE winds and building seas behind the cold front. Little change is expected elsewhere. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos