000 AXNT20 KNHC 241805 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 PM EDT SAT SEP 24 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... Tropical Storm Karl is centered near 32.8N 62.7W at 24/1500 UTC or about 109 nm east-northeast of Bermuda moving northeast at 16 kt. Estimated minimum central pressure is 994 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Heavy showers and thunderstorms are from 31N to 36N between 61W and 64W. Scattered moderate convection is elsewhere from 29N to 40N between 57W and 66W. Please see the latest NHC Public Intermediate Advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC AND NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. Lisa restrengthens to a Tropical Storm at 24/1500 UTC. Its center is near 24.7N 38.8W or about 982 nm northwest of the Cabo Verde Islands moving northwest at 9 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. There are scattered showers associated to Lisa NE of its center from 24N to 30N between 31W and 36W. Please see the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details. ...TROPICAL WAVES... A tropical wave is in the eastern Atlantic extending from 04N to 15N with axis near 25W, moving west near 20 kt over the past 24 hours. CIRA LPW imagery show shallow moisture in the wave environment with patches of dry air. The wave is also in a region of favorable deep layer wind shear, however no convection is observed at the time. A 1013 mb low is embedded in the monsoon trough ahead of the wave near 07N28W with scattered showers from 06N to 12N between 27W and 35W. The wave is going to merge with this broad area of low pressure late today. Then, this disturbance is expected to move rapidly westward across the tropical Atlantic Ocean for the next several days. Environmental conditions are expected to become conducive for gradual development, and a tropical depression could form while the system approaches the Lesser Antilles and moves into the Caribbean Sea by the middle of next week. A tropical wave is in the central Tropical Atlantic within 390 nm east of the Lesser Antilles. The wave extends from 07N to 20N with axis near 54W, moving west at 10 kt over the past 24 hours. The wave is in a region of favorable deep layer wind shear and shallow moderate moisture with some pockets of dry air. In the upper levels, water vapor imagery show strong dry air subsidence, which is limiting the convection to scattered showers from 18N to 21N and from 08N to 11N between 51W and 55W. A tropical wave is in the Bay of Campeche. The wave extends from 07N to 20N with axis near 95W, moving at 5 kt over the past 24 hours. Low level moisture convergence and diffluence aloft support scattered showers and isolated tstms across the SW Gulf of Mexico S of 23N. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 11N15W to a 1013 mb low near 07N28W to 06N38W. The ITCZ begins near 06N38W and continues to 09N52W to the coast of Guyana near 08N60W. For convection information see the tropical waves section. Otherwise, scattered showers are from 05N to 13N E of 21W. ...DISCUSSION... GULF OF MEXICO... Broad surface high pressure covering the E CONUS extends a ridge S to the N-NE Gulf of Mexico, thus supporting gentle variable winds in this portion of the basin. Gentle SE flow dominates over the remainder waters of the Gulf and draws moisture from the Caribbean Sea to support scattered showers and tstms N of 26N W of 89W. Similar convection is in the SW basin associated with a tropical wave. Please see the tropical waves section for further details. The wave will fully move to E Pacific waters tonight, leaving a weak low pressure center over the west Bay of Campeche that is forecast to dissipate Monday. CARIBBEAN SEA... A surface trough is off the Yucatan Peninsula extending from 21N86W to 15N88W generating isolated showers over the NW Caribbean Sea W of 82W, including the Yucatan Channel. The other area of convective activity is the SW basin where the E Pacific monsoon trough and a 1011 mb low near 09N76W support heavy showers and tstms S of 12N. Unfavorable or strong deep layer wind shear covers the majority of the remainder basin, thus providing stable conditions and fair weather. A tropical wave will enter the E Caribbean waters Sunday possibly enhancing showers across the Lesser Antilles. ...HISPANIOLA... Except for isolated showers across the NW Island, fair weather prevails elsewhere. An upper-level low will coupled with the easterly trade winds and enhance afternoon/evening showers and thunderstorms through the weekend. ATLANTIC OCEAN... The main features in the basin are TS Karl N of the forecast waters and TS Lisa, both discussed in the special features section. A tropical wave near the Cape Verde Islands has medium chance of becoming a tropical cyclone beyond the next two days. See tropical waves section for further details. Over the SW N Atlantic basin, a surface trough meanders from 30N78W to 25N80W to the the Straits of Florida near 24N82W supporting showers over S Florida and adjacent waters as well as the northern Bahamas. Surface ridging and fair weather prevails elsewhere. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS