599 AXNT20 KNHC 120517 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 117 AM EDT Sun Aug 12 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...SPECIAL FEATURE... Caribbean Gale Warning... Gale-force are expected tonight near the coast of Colombia and in the Gulf of Venezuela. A recent scatterometer pass depicted gale- force winds already occurring over the Gulf of Venezuela. These conditions will continue through Monday morning. The sea heights are forecast to range from 9 feet to 13 feet in this area. Please read the High Seas Forecast, that is listed under the WMO/AFOS headers FZNT02 KNHC/MIAHSFAT2 for more details. ...TROPICAL WAVES... An Atlantic tropical wave extends its axis along 37W from 21N southward, moving west at 10-15 kt. This wave is depicted in model diagnostics and 700 mb streamline analysis, and TPW imagery shows moderate moisture in its vicinity. Scattered showers are from 10N to 15N between 35W and 40W. An Atlantic tropical wave is along 49W from 21N southward, moving west at 10-15 kt. This wave is also depicted in model diagnostics. Scattered showers are in the area where the wave meets the ITCZ mainly south of 10N. A tropical wave in the eastern Caribbean extends its axis along 66W and south of 21N, moving west at 10-15 kt. Despite the fact that TPW imagery shows abundant moisture with this wave, no significant convection is observed at this time. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of west Africa near 14N17W to 09N42W. The ITCZ continues from 09N42W to 09N47, then resumes west of a tropical wave near 08N50W to 06N55W. Aside from the convection related to the tropical waves, scattered showers are noted along the boundaries east of 25W and between 32W-50W. ...DISCUSSION... GULF OF MEXICO... A surface ridge prevails across the basin, anchored by a 1018 mb high centered near 27N87W. With this, a gentle to moderate anticyclonic flow prevails across the area. To the southwest, a surface trough extends over the Bay of Campeche from 22N94W to 19N94W. Abundant cloudiness and scattered showers prevail across the west Gulf mainly west of 93W. An area of upper level diffluence prevails across the southeast Gulf waters enhancing scattered showers currently affecting the Florida Straits and Keys. The surface ridge will prevail across the area through early next week. The ridge will support moderate to fresh easterly 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... A Gale Warning is in effect for the south-central Caribbean. Refer to the section above for details. An upper-level low is centered near 18N75W. This feature is enhancing convection across the northwest Caribbean waters mainly north of 20W and west of 74W. A tropical wave extends its axis along 66W. For more information, refer to the section above. The monsoon trough extends along 10N between 76W-82W. Scattered showers are noted across Panama and Costa Rica due to this. Little change is expected through early next week. The next tropical wave will enter the eastern Caribbean by late Monday. ATLANTIC OCEAN... An upper level low is centered over the northwest Caribbean near 18N75W. This feature is also enhancing convection across the west Atlantic, mainly over the Bahamas. Two tropical waves are moving across the basin. Refer to the section above for details. The remainder of the basin is under the influence of a surface ridge, anchored by a 1026 mb high centered near 29N54W and a 1030 mb high near 35N35W. 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 also 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