000 AXNT20 KNHC 101743 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1243 PM 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 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...SPECIAL FEATURES... ...Gulf of Mexico Gale Warning... A strong area of high pressure dominates the Gulf of Mexico waters. The pressure gradient is strong enough to support gale force winds mainly south of 21N and west of 95W, with seas ranging between 10-16 ft. The ridge is forecast to shift eastward today, thus these gale winds will decrease by tonight. 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 07N11W to 05N13W. The ITCZ begins from 05N13W to 04N28W to 04N41W. A surface trough is embedded with the ITCZ extending from 08N31W to 05N31W. Scattered moderate convection is observed within 100 nm north of the ITCZ. ...DISCUSSION... GULF OF MEXICO... The main concern across the basin is the Gale Warning over Bay of Campeche. Please refer to the section above for details. A surface ridge extends across the northern Gulf and inland Mexico anchored by a 1032 mb high centered near 28N100W. A surface trough extends from 23N94W to 19N94W with scattered showers. A stationary front extends across the southern portion of the basin from 21N86W to 24N80W. A band of cloudiness and isolated showers prevails within 150 nm north of this front affecting portions of South Florida and the Keys, as well as the northern portion of the Yucatan Peninsula. Scatterometer data depicts moderate to fresh northerly winds across the central and east Gulf. Expect through the next 24 hours for the frontal boundary in the southern Gulf to weaken and dissipate. The pressure gradient will relax and gale force winds will weaken by tonight. CARIBBEAN SEA... A stationary front extends across the Yucatan Channel with isolated showers. An upper-level ridge extends across the western Caribbean with strong dry air subsidence supporting fair weather north of 15N and west of 78W. Over the central basin, a surface trough supported by a middle level inverted trough extends from 18N74W to a 1010 mb surface low near 10N77W. These features are under a upper-level diffluent environment that supports scattered moderate convection south of 14N between 76W-84W. Scatterometer data depicts fresh to locally strong easterly winds are occurring from 11N-18N between 73W and 80W, while moderate to fresh trades prevail elsewhere. Expect through the next 24 hours for the trough and low to continue moving west across the basin entering Central America. The stationary front will meander across the Yucatan Channel with associated conditions across spreading modestly into NW Caribbean. ...HISPANIOLA... Fair weather prevails across the island due to strong subsidence of dry air. An increase in low-level moisture will spread westward across the area today and should lead to passing tradewind showers mainly in the afternoon hours. Fair weather will prevail through the rest of the weekend. ATLANTIC OCEAN... A frontal system extends across the western Atlantic, analyzed as a stationary front from 24N80W to 28N66W then as a cold front from that point to 32N56W. A surface trough extending south of the cold front from 24N74W to 27N58W with no significant convection. South of this, another trough extends north of Puerto Rico from 23N65W to 20N66W with isolated showers. A surface ridge extends across the remainder of the basin anchored by a 1021 mb surface high centered near 26N42W and a 1026 mb high near 37N25W. Expect for the cold front in the west Atlantic to continue moving east. As the surface ridge behind this cold front begins to shift eastward into the Atlantic overnight and into Saturday, increasing northeasterly winds and building seas are expected behind the front. Little change is expected elsewhere. For additional information please visit http://www.hurricanes.gov/marine $$ ERA