000 AXNT20 KNHC 090958 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 558 AM EDT FRI SEP 9 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...TROPICAL WAVES... A tropical wave is in the central Atlantic extending from 06N to 17N with axis near 37W, moving W at 20 kt within the last 24 hours. There is a 1010 mb center of low pressure associated with the wave centered near 11N37W, which is forecast to move WNW to near 13N41W within the next 24 hours. The wave is in a region of mainly favorable to neutral deep layer wind shear and abundant moisture from the surface to 850 mb as indicated by CIRA LPW imagery. That environment along with divergent flow aloft support scattered showers and tstms from 06N to 17N between 31W and 43W. Some gradual development of this system is possible during the next several days, and a tropical depression could form while this system moves WNW into the central Atlantic by early next week. A tropical wave is in the central Caribbean waters extending from 11N to 19N with axis near 69W, moving W at 15 kt within the last 24 hours. The wave is in a region of neutral to unfavorable deep layer wind shear and water vapor imagery continue to show strong dry air subsidence, which hinder shower activity at the time. A tropical wave is entering the Yucatan Peninsula. The wave extends from 15N to 24N with axis near 87W, moving W at 15 kt within the last 24 hours. Abundant moisture in the wave environment, favorable deep layer wind shear and diffluence at the middle levels support isolated showers within 90 nm either side of its axis. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 14N17W to 13N31W to 08N42W. The ITCZ begins near 08N43W and continues to 06N57W. Aside from the convection related to the tropical wave along 37W, scattered moderate convection is observed south of the Monsoon Trough from 06N to 12N E of 29W. ...DISCUSSION... ...GULF OF MEXICO... A broad surface ridge across the Atlantic extends WSW across the Florida Peninsula and covers the Gulf waters, thus providing ESE gentle flow. The exception to this is the Bay of Campeche where winds are from the NE due to a tropical wave that is expected to move across the Yucatan Peninsula later this morning. Mainly unfavorable deep layer wind shear and strong dry air subsidence across the entire basin continue to favor fair weather. The tropical wave will move to the Bay of Campeche Friday night through Saturday with possible showers. Little changes expected elsewhere. ...CARIBBEAN SEA... The main feature in the basin continues to be a tropical wave that is moving across the far NW Caribbean waters generating scattered to isolated showers over central and eastern Cuba and adjacent waters N of 15N. A second tropical wave is just S of Dominican Republic. However, no shower activity is associated with it. Please refer to the tropical waves section for details. In the SW basin, scattered to isolated showers are S of 12N being supported by the E Pacific monsoon trough. Fair weather and moderate trades dominate elsewhere. The tropical wave will move to the Yucatan Peninsula later this morning. A surface trough will move WNW across the NE Caribbean this evening generating showers across Puerto Rico and adjacent waters. Shower activity associated with this trough will impact Hispaniola Saturday through Sunday. ...HISPANIOLA... Fair weather conditions prevail across the Island supported by both unfavorable deep layer wind shear and strong dry air subsidence from aloft. A surface trough moving WNW around the SW periphery of the Atlantic surface ridge will move over the Island Saturday through Sunday. Showers are expected during the weekend associated with this area of low pressure. ...ATLANTIC OCEAN... Diffluent flow between an elongated upper low over the NW Atlantic and a broad upper anticyclone centered over the Straits of Florida support scattered to isolated heavy showers across the central Bahamas and the Great Bahama Bank. That shower activity is also associated with a surface trough that extends from 25N78W to 21N79W. Scattered heavy showers are from 25N to 30N between 66W and 75W. Lastly, a surface trough in the deep tropics extending from 21N58W to 16N60W supports scattered showers and tstms from 17N to 20N between 54W and 63W. The remainder of the basin is dominated by a broad surface ridge anchored by a 1029 mb high centered N of forecast waters near 35N42W. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS