000 AXNT20 KNHC 180535 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 135 AM EDT THU AUG 18 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...SPECIAL FEATURES... Tropical Storm Fiona is centered near 15.5N 39.0W at 18/0300 UTC or about 865 nm W of the Cabo Verde Islands moving NW at 14 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Scattered moderate convection is from 15N-17N between 37W-40W. Please see the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCPAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... A tropical wave is moving across the eastern Atlantic with axis extending from 20N24W to 12N22W, moving west at 15-20 kt. The wave coincides with 700 mb troughing that has emerged off the coast of west Africa. Isolated showers are observed in the wave's environment between 20W-27W. A tropical wave extends across the central Atlantic with axis from 16N49W to 09N50W, moving west at 20 kt. Global model data indicates mid-level energy is focused along the wave axis with plenty of dry Saharan air and dust surrounding the wave. With this, no significant convection is observed across the wave. However, across the southern portion of the wave where it meets the Monsoon Trough, scattered moderate convection prevails south of 10N between 48W-51W. A tropical wave is moving across the eastern Caribbean with axis from 20N65W to 11N64W, moving west at 15-20 kt. The wave coincides with a westward surge of mid-level moisture as depicted by SSMI Total Precipitable Water imagery between 63W-68W. Despite this, no significant convection is observed at this time as Saharan dust and dry air prevails across the eastern Caribbean east of 65W inhibiting any activity. A tropical wave is moving across the Yucatan Peninsula with axis from 20N90W to 10N90W, moving west at 10-15 kt. Most of the energy associated with the wave is noted over the East Pacific region, however, scattered to numerous moderate convection is occurring across the southern portion of the Yucatan peninsula, Guatemala, and southern Mexico mainly south of 16N between 88W- 93W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 13N17W to 15N30W then resumes west of T.S. Fiona from 10N40W to 09N48W. The Intertropical Convergence Zone extends from 09N48W to 07N56W. Aside from convection associated with the tropical waves and Fiona, scattered moderate convection is from 10N-14N between 24W-30W and from 08N-10N between 51W-55W. ...DISCUSSION... GULF OF MEXICO... An upper-level anticyclonic circulation is centered over NE Mexico near 26N101W and is providing much of the western Gulf with a diffluent environment aloft. This diffluence along with gentle to moderate SE surface winds are generating isolated showers north of 25N and west of 90W. To the south; the proximity of a tropical wave currently moving over the Yucatan Peninsula is enhancing scattered moderate convection across the Bay of Campeche mainly south of 20N between 91W-95W. The remainder the the basin is under the influence of a surface ridge anchored by a 1020 high centered near 29N84W. An elongated upper-level low centered over the southeast Gulf and west Atlantic is enhancing convection across the Florida peninsula and Gulf waters mainly east of 85W. A similar weather patter will prevail through the next 24 hours. CARIBBEAN SEA... A tropical wave is moving across the eastern Caribbean. Please refer to the section above for details. The only area with convection at this time remains across the south-central Caribbean, where the proximity of the Monsoon Trough is enhancing scattered moderate convection south of 11N between 75W-80W. Scatterometer data depicts moderate to fresh trades across the basin except fresh to strong winds south of 13N between 73W-77W. Expect through the next 24 hours for the tropical wave to continue moving west with isolated convection. ...HISPANIOLA... Fair weather prevails across the island at this time. These conditions will prevail through the next 18-24 hours. A tropical wave currently along 65W will approach the island after that time and increase cloudiness and the possibility of precipitation. ATLANTIC OCEAN... Tropical Storm Fiona is moving across the eastern tropical Atlantic. Please refer to the Special Features section above for details. Two tropical waves are moving across the basin. For more information, refer to the section above. An elongated upper-level low extends from the southeast Gulf of Mexico to the west Atlantic supporting isolated showers mainly west of 78W. To the east; a pair of surface troughs extends from 29N66W to 26N68 and from 26N63W to 22N65W. Scattered moderate convection prevails along the second trough from 23N-29W between 61W-65W. The remainder of the basin is under the influence of a surface ridge anchored by a pair of 1023 mb and 1021 mb highs located near 32N66W and 31N24W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA