000 AXNT20 KNHC 200000 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 800 PM EDT WED OCT 19 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... An elongated non-tropical 1005 mb surface low is centered northeast of the Turks and Caicos near 25N69W with a surface trough extending from 20N76W through the low then to 30N62W. Scattered moderate convection extends from the central and east Caribbean to 31N between 62W-80W. This convection is supported by a diffluent flow aloft. Although the associated shower and thunderstorm activity remains disorganized, environmental conditions could become a little more conducive for the low to acquire some tropical characteristics during the next day or so, and this system could still become a subtropical or tropical cyclone before it merges with a cold front over the western Atlantic late Friday. Regardless of development, locally heavy rainfall continues to be a possibility through the next 24 hours across Hispaniola, Puerto Rico, and portions of the northern Leeward Islands. This system has a medium chance for tropical development within the next 48 hours. Please see the Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more details. ...TROPICAL WAVES... A tropical wave is in the east Atlantic with axis that extends from 14N36W to 06N36W, moving west near 15 kt over the past 24 hours. The wave coincides with a 700 mb trough depicted by model guidance and is embedded within a surge of moisture as noted in TPW imagery. Scattered moderate convection is from 05N-14N between 27W-41W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 15N18W to 07N29W to 08N40W. The ITCZ begins from that point and continues to 07N53W. Aside from the convection related to the tropical wave, scattered moderate convection is from 00N-06N between 20W-29W and from 05N-10N between 40W-49W. ...DISCUSSION... ...GULF OF MEXICO... A surface ridge extends across the basin anchored by a 1019 mb high centered near 32N85W. As of 19.2100 UTC, a surface trough developed over the northwest Gulf waters enhancing convection from 24N-28N between 93W-96W. Another surface trough extends across the Bay of Campeche from 22N95W to 19N93W. Scatterometer data depicts a light to gentle easterly flow west of 90W while a gentle to moderate easterly flow prevails east of 90W. Expect through the next 24 hours for the surface ridge to persist then will retreat east ahead of a cold front that will move into the northwest Gulf by Thursday. The front will move across the basin through the weekend enhancing winds/convection. ...CARIBBEAN SEA... A weak 1009 mb surface low is located across the southwest Caribbean waters near 15N83W with a trough extending from the low to 16N79W to 18N76W. The central and east Caribbean is under the influence of the surface low that was described in the Special Features section above. A diffluent flow aloft is keeping the area east of 80W with constant convection mostly affecting Hispaniola, Puerto Rico and the U.S Virgin Islands. Scatterometer data depicts gentle to moderate trades across the basin. Expect through the next 24 hours for the surface low over the southwest Caribbean to dissipate. The convection will continue across the central and eastern portions of the basin as the Special Features' low continues northwest of Hispaniola and the upper-level support persists. ...HISPANIOLA... The deep layered trough over the west Atlantic extends over the island generating scattered showers over the island with possible isolated thunderstorms. These conditions will continue through the next 24-48 hours. ...ATLANTIC OCEAN... A deep layered trough extends over the west Atlantic from 60W- 80W supporting the surface low and trough described in the Special Features section above. To the east of this system; a surface trough extends from 23N49W to 31N37W. A tropical wave extends along 36W. Please refer to the section above for details. Another surface trough extends across the eastern Atlantic from 28N30W to 28N23W. Expect for the Special Features' low in the west Atlantic to move northwest through late Thursday before exiting off the east-northeast this weekend. Fresh to near gale force winds will continue mainly on the northwest side of the low. A cold front will move into the west Atlantic this weekend. For additional information please visit http://www.hurricanes.gov/marine $$ ERA