000 AXNT20 KNHC 130558 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1258 AM EST Mon Nov 13 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 09N13W to 09N18W. The Intertropical Convergence Zone axis extends from 09N18W to 06N36W to 07N43W to 04N51W. Scattered moderate isolated strong convection is from 05N-14N between 19W-44W. ...DISCUSSION... GULF OF MEXICO... An upper level trough extends from the Great Lakes SSW to a base over the SW Gulf basin, which is supporting a surface trough from SE Louisiana adjacent waters near 28N89W to 23N91W. Isolated showers are occurring within 150 nm E of the surface trough axis N of 26N. The tail of a shear line that is across S Florida extends into the SE Gulf from 26N81W to 25N83W. South of this boundary, southerly diffluent flow supports scattered showers and isolated tstms across the Yucatan Channel, the E Yucatan Peninsula and the Florida Straits. Otherwise, surface ridging prevails elsewhere. A tight pressure gradient between the ridge and lower pressure over the W Caribbean supports fresh to locally strong ENE winds E of 90W, including the aforementioned areas being affected by convection. Moderate to fresh NNE winds are elsewhere. The shear line is expected to slowly dissipate through Monday night as stronger NE winds weaken. CARIBBEAN SEA... Broad low pressure prevails across the western Caribbean underneath a middle level low in the NW basin and southerly upper level diffluent flow. This atmospheric scenario supports a surface trough along 18N78W to 14N79W with associated numerous heavy showers and tstms from 14N-19N between 77W-81W and scattered moderate convection and tstms elsewhere W of 75W. Middle to upper level diffluence support scattered showers across the western half of Hispaniola and isolated showers across the remainder Dominican Republic. A middle level ridge and dry air aloft provide stability and generally fair weather to the eastern half of the Caribbean. A tight pressure gradient between high pressure N of the area and the broad area of low pressure in the western half of the Caribbean supports fresh to locally strong winds in the NW Caribbean N of 14N W of 75W. The synoptic pattern aloft will continue in place through Monday as the upper level troughing over the Gulf of Mexico and SW North Atlc will be slow to weaken into early next week. Otherwise, moderate to occasional fresh trades E of 75W will persist. ...HISPANIOLA... Middle to upper level diffluence support scattered showers across the western half of Hispaniola and isolated showers across the remainder Dominican Republic. This overall pattern will persist through Tuesday. ATLANTIC OCEAN... Southwesterly to westerly flow aloft support cloudiness and possible isolated showers across the Grand Bahama Bank and the northern and central Bahamas. To the east, middle to upper level diffluence support scattered showers N of the Windward Passage and Hispaniola to 21N. To the N of this region, a shear line extends from 28N66W to 26N74W to Florida near 26N80W. In the NE basin, a 1013 mb low is centered near 29N34W. Environmental conditions are expected to be conducive for some additional development, and the system could become a subtropical cyclone during the next few days while it moves slowly northeastward. There is a low chance of cyclogenesis within the next 48 hours. Lastly, a surface trough extends from 25N25W to the Cape Verde Islands supporting showers there and northward from 15N-30N between 21W-33W. Otherwise, surface ridging prevails elsewhere. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos