000 AXNT20 KNHC 111730 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 130 PM EDT SUN SEP 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... A vigorous tropical wave is in the central Atlantic associated with a 1009 mb low pressure centered near 16N47W. The wave extends from 10N to 23N with axis near 47W, moving W at 5 kt within the last 24 hours. Scattered showers and isolated tstms are from 10N to 23N between 40W and 51W. Gale force winds are in the NE quadrant of the low center.Please see the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. There is a high chance of tropical development later today or on Monday before upper-level winds become less conducive for development. The low is expected to move NW over the central Atlantic Ocean during the next few days. Please see the latest NWS Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more details. ...TROPICAL WAVES... A tropical wave in the E Atlantic extends from 10N to 20N with axis near 20W, moving W at 5 kt within the last 24 hours. A moderate moist environment from the surface to 850 mb, favorable deep layer wind shear and diffluent flow aloft support scattered showers and tstms from 10N to 15N E of 25W. A tropical wave in the E Atlantic extends from 09N to 17N with axis near 29W, forecast to move W at 15 kt within the next 24 hours. The wave is in a region of favorable deep layer wind shear, however Saharan dry air and dust in the northern wave environment limit the convection to scattered showers from 07N to 10N between 25W and 33W. A tropical wave is in the W Caribbean extending from 10N to 21N with axis near 84W moving W at 10 kt within the past 24 hours. A moderate moist environment from the surface to 850 mb, favorable deep layer wind shear in the SW basin and diffluent flow aloft support scattered showers and tstms from 09N to 15N W of 79W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 14N17W and continues along 09N30W to 11N41W. Aside the convection associated with the tropical waves discussed above, scattered moderate convection is from 04N to 10N E of 18W and from 03N to 07N between 32W and 38W. ...DISCUSSION... ...GULF OF MEXICO... Surface low pressure is present in the SE and SW portions of the basin. In the SE Gulf, a 1015 mb low is centered near 23N85W with associated trough extending from 26N85W to the low to 21N85W. Dry air subsidence from aloft, low moisture and neutral to unfavorable deep layer wind shear in that portion of the basin limit the convection to scattered showers and tstms within 90 nm from the low center. Scatterometer data show gentle variable wind associated with the low and gentle E wind in the NE Gulf. North to northeasterly gentle flow linked to a broad surface ridge covering the central U.S. and central Mexico dominates the basin W of 90W. Aloft, the base of an upper trough reaches the NW basin and along a ridge to the east generate diffluent flow that support scattered heavy showers and tstms within 210 nm off the SE Louisiana, Mississippi and Alabama coasts between 86W and 91W. Lastly, a surface trough in the SW basin extends from 21N93W to 16N95W supporting scattered showers in the Bay of Campeche W of 92W. A tropical wave currently over the W Caribbean will enter the Yucatan Peninsula near sunrise Monday and then will move across the Bay of Campeche through Tuesday. ...CARIBBEAN SEA... The main feature in the basin is a tropical wave moving across the W Caribbean. Aloft, an upper ridge anchored over Southern Mexico extends E to the NW Caribbean and along with an upper level low over Hispaniola generate diffluent flow in the SW basin to support the convection associated with the tropical wave. See tropical waves section for further details. A 1012 mb low is off the coast of Colombia connected to the E Pacific monsoon trough, which is supporting scattered showers within 60 nm of the low center. The upper low over Hispaniola and a broad area of low pressure moving across the southern Bahamas support isolated showers and tstms over Hispaniola. The remainder basin is under the influence of dry air subsidence from aloft. which is supporting fair weather. In terms of winds, generally moderate trades prevail across the basin. The tropical wave will move to the Yucatan Peninsula near sunrise Monday. Showers across Hispaniola are expected through early Tuesday morning. ...HISPANIOLA... An upper-level low centered over the Island and a broad area of low pressure moving across the southern Bahamas support isolated showers and tstms over Hispaniola. This shower activity is expected to continue through early Tuesday morning. ...ATLANTIC OCEAN... The primary feature of concern in the basin is invest area AL94 located in the central tropical Atlantic. This disturbance associated with a tropical wave has a high chance of become a tropical cyclone later today or tomorrow. Currently, there is a gale warning due to it. Please see the special features section for details. A second area of disturbed weather is in the SW N Atlantic waters with scattered heavy showers and tstms over the Bahamas, Turks and Caicos Islands and the Great Bahamas Bank. There are no signs of a surface circulation, and conditions do not appear conducive for significant development of this disturbance while it moves NW. Heavy rainfall is possible over portions of the Bahamas through Monday. Surface ridging anchored by a 1025 mb high N of the area dominate the remainder Atlantic waters. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS