179 AXNT20 KNHC 112355 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 755 PM EDT Sat Aug 11 2018 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 FEATURE... GALE-FORCE WINDS NEAR THE COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA... Frequent gusts to GALE-FORCE are expected to develop tonight near the coast of Colombia and in the Gulf of Venezuela. Expect NE to E winds 20 to 30 knots, from 11N to 13N between 70W and 76W. Sea heights will range from 9 feet to 12 feet. On Sunday night, GALE- FORCE NE winds are expected within 90 nm of the coast of Colombia, and frequent gusts to GALE- FORCE winds in the Gulf of Venezuela. The sea heights are forecast to range from 9 feet to 13 feet. Please read the High Seas Forecast, that is listed under the WMO/AFOS headers, as FZNT02 KNHC/MIAHSFAT2, for more details. ...TROPICAL WAVES... An Atlantic tropical wave is along 36W from 21N southward. Scattered showers are from 10N to 16N between 30W and 40W. This precipitation is related to the proximity of the monsoon trough. An Atlantic tropical wave is along 47W from 21N southward. Scattered showers are from 09N to 12N between 40W and 47W. This precipitation is also related to the proximity of the monsoon trough. A Caribbean tropical wave is along 64W from 21N southward. No significant convection is observed with this wave at this time. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of west Africa near 14N17W to 08N46W. The ITCZ continues from 08N46W to 04N50W. Aside from the convection related to the tropical waves, scattered showers are noted along the boundaries between 30W-50W. ...DISCUSSION... GULF OF MEXICO... An upper level cyclonic circulation center is near 24N87W. Upper level cyclonic wind flow covers the Gulf of Mexico from 90W eastward. Isolated moderate rainshowers are to the east of the line that runs from SE Louisiana to the Florida Keys, and from 26N northward from 90W westward. A surface trough is in the SW corner of the Gulf of Mexico, along 92W/94W, from 22N southward into the Isthmus of Tehuantepec of southern Mexico. Upper level anticyclonic wind flow covers the Gulf of Mexico from 26N southward from 90W westward. Scattered moderate to isolated strong rainshowers are along the coast of Mexico from 26N southward from 94W westward. Other broken multilayered clouds and possible rainshowers are elsewhere from 26N southward from 88W westward. A surface ridge passes across the NW Bahamas, to a 1018 mb high pressure center that is near 27N88W, and it continues to the lower Rio Grande Valley of Texas. Gentle to moderate anticyclonic wind flow covers much of the Gulf of Mexico. Light to gentle winds cover the NE part of the area. The sea heights are in the range of 1 foot to 2 feet in the NE corner of the area, and in the range of 2 feet to 4 feet elsewhere. The current surface ridge will prevail across the area through early next week. The ridge will support moderate to fresh SE winds in the west-central and NW Gulf. A nocturnal trough moving off the Yucatan peninsula will induce a surge of fresh to strong NE to E winds in the Bay of Campeche each night. CARIBBEAN SEA... An upper level cyclonic circulation center is near 23N73W in the Atlantic Ocean. A trough extends from the 23N73W cyclonic center to 14N76W in the Caribbean Sea. Upper level cyclonic wind flow covers the Caribbean Sea from 14N northward between 63W and 84W. Isolated moderate rainshowers are from 15N northward between the Mona Passage and 83W. The monsoon trough is along 08N/09N, from 73W in Colombia beyond southern Costa Rica. Widely scattered moderate to isolated strong rainshowers are from 12N southward from 80W westward, in the coastal plains/coastal waters from Panama to Costa Rica to Nicaragua. High pressure, that is to the north of the area, will support fresh to strong winds in the south central Caribbean Sea through Tuesday. Frequent gusts to gale force are expected in the Gulf of Venezuela and near the coast of Colombia tonight and Sunday night. It is possible that sustained wind speeds may reach gale force along the coast of Colombia on Sunday night. One tropical wave is entering the eastern Caribbean Sea. The next tropical wave will enter the Caribbean Sea on Monday night. ATLANTIC OCEAN... An upper level cyclonic circulation center is near 23N73W. A trough extends from the 23N73W cyclonic center to 14N76W in the Caribbean Sea. Upper level cyclonic wind flow covers the Caribbean Sea from 14N northward between 63W and 84W. Isolated moderate to locally strong rainshowers cover the Atlantic Ocean from the Greater Antilles northward elsewhere from 60W westward. Rainshowers that are associated with a 62W/63W tropical wave are from 18N to 23N between 60W and 65W. An upper level cyclonic circulation center is near 36N49W. Upper level cyclonic wind flow covers the Atlantic Ocean from 28N northward between 40W and 58W. Isolated moderate rainshowers are from 28N northward between 44W and 57W. A surface ridge extends from a 1030 mb high pressure center that is near 35N30W, through 32N42W, to 27N56W 27N73W, across the south Florida peninsula, to a Gulf of Mexico 1020 mb high pressure center that is near 25N87W. The current surface ridge will remain in place during the next several days. The ridge will help to maintain gentle to moderate anticyclonic flow N of 22N, and mainly moderate easterly winds will prevail S of 22N. This scenario will support fresh to locally strong winds along the N coast of Hispaniola and the approaches to the Windward Passage during the evening and nighttime hours. For additional information please visit http://www.hurricanes.gov/marine $$ ERA/MT