000 AXNT20 KNHC 260003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 803 PM EDT SUN SEP 25 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 2345 UTC. ...TROPICAL WAVES... A tropical wave is in the central Atlantic extending from 04N to 15N with axis near 39W, moving W at 25 kt over the past 24 hours. The wave is associated with a 1012 mb low centered near 07N39W, which is forecast to be near 07N45W within the next 24 hours. Abundant low to middle level moisture, favorable deep layer wind shear and a diffluent flow aloft support heavy showers and isolated tstms within 420 nm NW semicircle from the low pressure center. Isolated showers are elsewhere. A tropical wave has entered the far E Caribbean. The wave extends from 10N to 20N with axis near 62W, moving W at 15 kt over the past 24 hours. Even though the wave is embedded in a favorable region of deep layer wind shear in the Atlantic and NE Caribbean, water vapor imagery show strong dry air subsidence, which is limiting convection to the Windward Islands and adjacent SE Caribbean waters. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 09N13W to 09N28W to a 1012 mb low near 07N39W to 06N44W. The ITCZ begins near 06N44W and continues to 08N54W. Aside from the convection related to the tropical wave in the central Atlantic, heavy showers and isolated tstms are off the coast of W Africa from 10N to 15N E of 19W. ...DISCUSSION... GULF OF MEXICO... Weak surface ridging prevails across the basin, which provide gentle NE to E flow east of 90W and mainly SE gentle to moderate flow elsewhere. Over the SW basin, a surface trough extends from 23N94W to 17N95W that support scattered heavy showers off the W Yucatan Peninsula and scattered showers elsewhere across the Bay of Campeche. Middle level diffluence and abundant low to middle level moisture support scattered showers over Texas coastal waters, the Yucatan Channel and N Yucatan Peninsula adjacent waters to 24N. A weak cold front will enter the NW basin before sunrise Tuesday. By Thu morning the front will extend from Jacksonville SW to W across the northern Gulf waters. CARIBBEAN SEA... Middle level diffluent flow and abundant moisture in the northern Caribbean support heavy showers and tstms along Cuba, Jamaica and W-SW Hispaniola. Isolated showers are across W Puerto Rico and La Mona Passage supported by an upper level low. Scattered showers are within 90 nm off the E Yucatan Peninsula and in the Yucatan Channel and in the SW basin where is supported by the E Pacific monsoon trough. A tropical wave is moving across the Lesser Antilles and far E Caribbean waters generating showers for the Windward Islands and adjacent waters. Fair weather is elsewhere being supported by unfavorable deep layer wind shear and strong dry air subsidence. Otherwise, gentle to moderate trades dominate elsewhere, except off the Gulf of Venezuela and northern Colombia coastal waters. The tropical wave is forecast to move across Hispaniola Tuesday with showers. ...HISPANIOLA... Middle level diffluent flow and abundant moisture in the northern Caribbean support heavy showers and tstms over W-SW Hispaniola. This shower activity is forecast to cease before sunrise Monday, however will resume in the late afternoon/early evening as a tropical wave approaches and moves across the Island Tuesday. ATLANTIC OCEAN... The main feature in the basin is a tropical wave with high chances of becoming a tropical cyclone past the next 48 hours. See tropical waves section. The remnants of Lisa are analyzed as a 1014 mb low near 28N42W with isolated showers within 120 nm N semicircle. A surface trough prevails along the E Florida Peninsula adjacent waters that along with a broad area of diffluent flow in the upper levels support scattered heavy showers and tstms from 22N to 29N between 74W and 79W. Farther east, a pre-frontal trough extends from 30N54W to 26N60W to 22N64W with scattered to isolated showers within 90 nm either side of its axis. Otherwise, surface ridging dominates elsewhere in the central and eastern Atlantic. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS