000 AXNT20 KNHC 151202 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 802 AM EDT Fri Jun 15 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 0600 UTC surface analysis and satellite imagery through 1115 UTC. ...TROPICAL WAVES... A tropical wave is in the E Atlantic with axis extending from 13N28W to 03N29W, moving W at 10 kt. The TPW shows moderate moisture associated with the wave. The GOES-16 Geocolor RGB imagery shows the presence of the Saharan dust and dry air N of the wave at 15N. Isolated moderate convection is noted where the wave meets the ITCZ. A tropical wave is in the central Atlantic with axis extending from 13N45W to 03N46W, moving W at 10-15 kt. The Saharan Air Layer from CIMSS shows the wave has dry air and dust N of 13N. Isolated moderate convection is behind the wave's axis and N of the ITCZ from 7N-10N between 37W-45W. A tropical wave is just E of the Windward Islands with axis extending from 15N60W to 07N61W, moving W at 5-10 kt. The Saharan Air Layer dust and dry air is N of 10N. Shallow moisture with embedded showers is associated with the wave, and will affect the Windward Islands and the eastern Caribbean today. A tropical wave is over the W Caribbean with axis along 82W from 10N-19N. Scattered showers and tstms are over the SW Caribbean, likely a combination of the wave and the proximity of the Monsoon Through. The wave will move westward into Central America through Sat. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 12N15W to 08N20W. The ITCZ extends from 08N20W to 06N28W to 08N38W to , the coast of South America near 06N56W. Besides the convection mentioned in the tropical waves section, scattered moderate convection is seen from 09N- 11N between 14W-16W, and from 5N-7N between 17W-22W. ...DISCUSSION... GULF OF MEXICO... A surface ridge dominates the Gulf waters, with a 1017 mb high pressure located over SE Louisiana. Scattered showers and thunderstorms are noted over the western Gulf under a SE wind flow. This convective activity is generating by an upper-level low. A surface trough across the Bay of Campeche and western Gulf will shift slowly WNW through Sat, accompanied by widespread convection. The pressure gradient will tighten in association with this trough, and produce freshening SE winds across W central portions today, becoming fresh to strong SE to S winds over the weekend. The GFS computer model indicates increased SE flow by Sat to 25-30 kt in association with Yucatan thermal trough combining with persistent troughing. Expect significant area of 25 kt and seas to 11-12 ft Sat afternoon but likely could see 30 kt. CARIBBEAN SEA... Abundant cloudiness with embedded showers and tstms are noted over the NW Caribbean, and parts of the Yucatan Peninsula, including also the Yucatan Channel. A diffluent pattern aloft is helping to induce this convective activity. Scattered showers and tstms are also seen over the SW Caribbean just N of Panama. Two tropical waves are moving westward across the basin. Please, see Tropical Wave section for details. Strong trades across the central Caribbean between 70W and 85W will diminish this weekend. ATLANTIC OCEAN... A ridge, anchored by a 1029 mb high pressure centered just SW of the Azores dominates the Atlantic Ocean. The ridge will drift southward through Sun as a weak cold front sweeps eastward across the waters north of 25N. Moderate easterly winds are expected south of the ridge. Gentle to moderate southerly flow north of the ridge will moderate to fresh southwesterly flow ahead of the front this weekend. For additional information please visit http://www.hurricanes.gov/marine $$ GR