000 AXNT20 KNHC 112348 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 648 PM EST SUN DEC 11 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across the African Continent entering the Atlantic Ocean through Liberia near 07N11W to 05N18W. The ITCZ axis begins at 05N18W and extends through 04N30W to 06N40W. A surface trough is embedded within the ITCZ extending from 10N42W to 03N43W. Scattered moderate isolated strong convection is N of 02N to the coast of Africa between 05W and 09W. Similar convection is within 75 nm S of axis between 29W and 31W, and from 01N to 03N between 34W and 37W. Isolated showers are near the trough axis. ...DISCUSSION... GULF OF MEXICO... High pressure located NE of the region extends a ridge across the SE CONUS and the Gulf of Mexico into central Mexico with a 1020 mb high pressure inland between Tampico and Tuxpan Mexico. The remnants of a frontal boundary remains across the SE Gulf stretching from across the Straits of Florida to 23N88W to 21N93W. The most recent scatterometer pass showed the presence of a surface trough across the SW Gulf, extending from near Tampico Mexico to the western Bay of Campeche near 19N95W. Under this weather pattern, fresh to locally strong southerly flow has developed over the NW Gulf, while fresh to locally strong easterly winds are noted over the eastern Gulf north of the frontal boundary to about 26N. Multilayered clouds with embedded showers and isolated tstms are over the SW Gulf. The high pressure located NE of the area will continue to slide eastward with a 1020 mb high pressure developing over the NE Gulf on Monday. This system will likely persist through Wednesday. The next cold front is forecast to reach the N and NE Gulf Wednesday night followed by another strong high pressure system. This will result in increasing N-NE winds, mainly across the N waters on Thursday. Aloft, an upper-level trough is over the NW Gulf. Southwesterly flow ahead of the trough dominates the remainder of the Gulf. CARIBBEAN SEA... An area of showers and thunderstorms persists over the SW Caribbean associated with a surface low pressure located near 10N81W. The strongest convection associated with this system is currently over waters, affecting mainly the area from 12N to 15.5N between 79W and 83W. A well defined diffluent pattern aloft is helping to induce this convective activity. Computer model indicates that all this moisture will spread across northern central America and the Gulf of Honduras on Monday and will likely persist on Tuesday. Locally heavy rain, with the potential of flash flooding and mudslides could occur over parts of northern Costa Rica, Nicaragua and Honduras through Monday. Fresh to strong trades are blowing over the south-central Caribbean based on scatterometer data. Moderate to fresh trades are noted across the remainder of the central Caribbean and eastern part of basin while mainly moderate NE winds are observed over the NW Caribbean. These winds will persist over the next couple of days, and are forecast to diminish by Wednesday as high pressure N of area moves eastward and slightly weakens. ...HISPANIOLA... Moisture is expected to diminish on Monday as the inverted trough currently located just north of the island continues to moves westward. Another patch of moisture will approach from the east on Tuesday. Light showers could occur on Monday mainly in the afternoon due to local effects. ATLANTIC OCEAN... A weakening stationary front extends across the western and central Atlantic from 31N47W to 26N60W to 25N70W to the Straits of Florida. A broken band of cloudiness with isolated showers is associated with the front, forecast to dissipate across the waters W of 65W tonight into Monday. Strong high pressure in the wake of the front supports fresh to strong easterly winds S of 28N W of 65W. These winds will gradually diminish through Tuesday. East of the front, a pair of 1025 mb high pressure areas are located near 29N39W and near 32N24W with a ridge across the Tropical Atlantic. Moderate to fresh easterly winds are seen across the southern periphery of the ridge, particularly S of 21N. A ridge will continue to dominate the waters between west Africa and the Lesser Antilles, with fresh to strong trades W of about 40W Monday and Monday night. An upper-level low is spinning between the Madeira and the Canary Islands generating isolated showers. For additional information please visit http://www.hurricanes.gov/marine $$ GR