000 AXNT20 KNHC 171150 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 AM EDT SAT SEP 17 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 1130 UTC. ...SPECIAL FEATURES... Tropical Depression Julia is centered near 30.1N 76.4W at 17/0900 UTC or about 245 nm southeast of Charleston, South Carolina. Ju7lie remains stationary. Estimated minimum central pressure is 1009 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. Please see the latest NHC Forecast/ Advisory under the AWIPS/WMO headers MIATCMAT1/WTNT21KNHC for more details. No associated deep convection. Scattered showers and isolated thunderstorms are from 28N-31N between 69W-74W. Tropical Storm Karl is centered near 18.2N 38.2W at 17/0900 UTC or about 660 nm west of the Cabo Verde Islands and about 1350 nm east of the Leeward Islands moving west at 12 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Please see the latest Forecast/Advisory under the AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. Scattered moderate to isolated strong convection is from 18N-22N between 22W-37W and within 60 nm of the center over the north-northwest quadrant. A tropical wave located just offshore of the west coast of Africa extends along 18W-19W from 10N-17N with a 1009 mb low near 12N18W moving west 5 to 10 kt over the past 24 hours. Wave coincides with a global model 700 mb trough and is embedded within a surge of moisture as shown on the Total Precipitable water imagery. Numerous strong convection is within 30/45 nm of a line from 12N21W to 16N17W. Scattered moderate to isolated strong convection are from 11N13N between 18W-22W and from 13N- 18N west of 23W to just inland over Africa. Environmental conditions appear conducive for gradual development, and a tropical depression could form by the middle of next week. Regardless of tropical cyclone formation, this system could bring rain and gusty winds to portions of the Cabo Verde Islands during the next couple of days. This system has a medium chance of tropical formation within the next 48 hours. Near gale-force winds are forecast for the area of Agadir. Please refer to the METEO-FRANCE High Seas Forecast, that is listed under the following links: MARINE...BULLETINS EXPERTISES...GRAND LARGE...METAREA II...or on the website: WWW.METEOFRANCE.COM/PREVISIONS-METEO-MARINE/BULLETIN/ GRANDLARGE/METAREA2. ...TROPICAL WAVES... Tropical wave in the west Tropical Atlantic extends along 55W from 11N-21N moving west 10 to 15 kt over the past 24 hours. Wave coincides with a global model 700 mb trough. No associated showers or deep convection. ...ITCZ/MONSOON TROUGH... Monsoon trough extends across Africa into the Tropical Atlantic near 16N16W then south through the 1009 mb low near 12N18W continuing to 13N32W. The ITCZ extends from 8N42W along 8N47W 11N52W to over Trinidad. Small clusters of scattered moderate convection are from 4N-10N between 13W-21W. Small clusters of Isolated moderate convection are from 5N-8N between 21W34W. ...DISCUSSION... GULF OF MEXICO... An upper ridge dominates the Gulf tonight anchored near 26N91W and extending a upper ridge axis southwest over Mexico near Tuxpan and northeast over the CONUS to over New England and the Great Lakes. At the surface, a weak surface ridge extends from along the eastern seaboard over the northeast Gulf to 26N88W. A mid level low is centered over the north/central Gulf generating Scattered showers and possible isolated thunderstorms north of 27N to over the north Gulf coast between 84W-95W. Scattered showers and isolated thunderstorms are from 25N-27N 90W-94W. The diurnal surface trough extends from 22N91W to inland over Mexico to 17N93W generating scattered showers and isolated thunderstorms over the Bay of Campeche south of 21N west of the surface trough to 95W. the mid level low will continue to bring showers and thunderstorms to the north Gulf through Sunday. The diurnal surface trough will develop over the Yucatan peninsula each evening, moving into the southwest Gulf waters late each night, then dissipating each morning. CARIBBEAN SEA... A cutoff upper low is over the northeast Caribbean near 20N83W extending an upper trough south to the coast of Honduras and north across west Cuba. This is generating scattered showers and possible isolated thunderstorms north of 17N to the coast of Cuba between 77W-81W. Scattered showers and isolated thunderstorms are within 60 nm along the coast of Nicaragua and Honduras north of 12N east of 86W. An upper ridge covers the central Caribbean anchored over southwest Haiti and covers most of the remainder of the Caribbean with the exception of the far northeast Caribbean. A second upper low is over the far northeast Caribbean centered east of the northern Leeward Islands near 19N61W and supporting a surface trough that extends from 21N59W across the Lesser Antilles near between Dominica and Martinique to 14N62W generating scattered showers and isolated thunderstorms from 13N-17N between 58W-62W, east of the Leeward Islands to the surface trough south of 19N, and from 12N-14N between 62W-65W. The remainder of the Caribbean is under clear skies this morning. Strong trade winds will develop across the south/central Caribbean along the coast of Colombia this afternoon through early Monday. A tropical wave will enter the east Caribbean Saturday night through Monday. ...HISPANIOLA... An upper ridge covers Hispaniola anchored over southwest Haiti. This is giving the island clear skies again this morning. Fair weather is expected across the island through Sunday night as the upper ridge persists. The tropical wave that will enter the Caribbean Saturday night will reach the island Sunday night into Monday. ATLANTIC OCEAN... Primary features of concern are Tropical Storms Karl in the central Atlantic and Tropical Depression Julia off the southeast CONUS. See Special Features above. A small upper low is over the Bahama Islands near 26N75W. A surface trough extends from 32N56W to 25N66W generating scattered showers and isolated thunderstorms within 60 nm either side of the surface trough. An upper ridge anchored near 25N68W with an upper low centered near 21N53W is creating a diffluent environment to generate scattered showers and isolated thunderstorms within 45 nm of a line from 24N57W to 30N56W and north of 30N between 52W-56W. The east Atlantic is dominated by a surface ridge anchored by a 1029 mb high northeast of the Azores. Tropical Depression Julia is expected to be a remnant low later today moving slowly northwest through Sunday then turn northward Sunday night. Tropical Storm Karl is expected to move west through Sunday night then turn west-northwest early Monday. For additional information please visit http://www.hurricanes.gov/marine $$ PAW