000 AXNT20 KNHC 051804 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 204 PM EDT Wed Jul 5 2017 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... A 1009 mb surface low is centered near 11N36W. A tropical wave extends through the low from 06N to 18N. Numerous heavy showers and tstms are from 10N to 13.5N between 36W and 39W. Scattered showers are elsewhere from 06N to 14N between 35W and 40W. Environmental conditions remain favorable for tropical cyclone formation today or Thursday while the low moves westward or west-northwestward at 10 to 15 mph across the tropical Atlantic. The system has a medium chance of becoming a tropical cyclone during the next 48 hours. ...TROPICAL WAVES... A tropical wave over the central Atlantic has an axis near 53W extending from about 08N to 20N, moving west at about 20 kt during the last 24 hours. This wave had spun off the surface low now well to the east of the wave axis. The wave is in a region of favorable to neutral wind shear. However, extensive intrusion of Saharan dry air and dust to the wave environment hinder convection at the moment. A tropical wave located over the central Caribbean has an axis near 70W extending from about 10N to 20N, moving west at around 15 kt during the past 24 hours. The wave is in a region of unfavorable wind shear S of 17N and favorable wind shear northward. Abundant moisture is associated with this wave W of its axis. Middle to upper level diffluence over Hispaniola support scattered heavy showers and tstms from 17N to 21N between 65W and 71W. Isolated showers are elsewhere between 65W and 75W. A tropical wave is moving across northern Central America and the Yucatan Peninsula. Its axis is near 88W from 12N to 22N and it has been moving westward at about 15-20 kt. Although the wave is in a region of unfavorable wind shear, moderate low level moisture along with middle to upper level diffluence support scattered heavy showers and tstms over Belize, northern Guatemala and the Gulf of Honduras as well as from 16N to 19N between 80W and 85W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the Senegal coast at 12N16W to 08N20W to 08N30W. The Intertropical Convergence Zone extends from 10N44W to 09N54W to 10N60W. Aside from the convection related to the Special Feature's low/wave, scattered moderate isolated strong convection is observed from 04N to 08N E of 20W as well as from 0N to 09N between 36W and 49W. ...DISCUSSION... GULF OF MEXICO... A weak surface ridge extends across the northern Gulf anchored by a 1021 mb high near 29N85W, which is forecast to stall through tomorrow morning. A pair of surface troughs are in the SW basin, one extending from 24N96W to 18N96W with isolated showers and tstms between Jalapa and Tampico, Mexico. Isolated showers are elsewhere in the western half Bay of Campeche. The second trough extends from 26N89W to 18N92W with isolated showers N of the Yucatan Peninsula to 24N. Otherwise, shallow moisture and diffluent flow aloft support isolated showers and tstms in the SE Gulf S of 26N E of 86W. Scatterometer, ship, and buoy observation indicate that the surface winds across the Gulf are light to moderate breeze. Little change in this pattern is expected during the next couple of days. CARIBBEAN SEA... Two tropical waves are moving across the Caribbean, one generating shower activity over the NW basin and the other to the north- central Caribbean. Refer to the section above for details. The moderate pressure gradient over the Caribbean between the Bermuda high to the north and the Colombian low to the south is maintaining gentle to fresh tradewinds over the basin, except over the waters north of Colombia and Venezuela where fresh to near gale force easterlies are pulsing every night lasting through the early morning hours. Little change is expected in the surface winds during the next couple of days. ...HISPANIOLA... A tropical wave located over the central Caribbean carrying abundant moisture with it along with middle to upper level diffluence over the Dominican Republic support scattered heavy showers and tstms from 17N to 21N between 65W and 71W. Isolated showers and tstms are over Haiti. Shower activity will continue through Thursday morning. ATLANTIC OCEAN... Two tropical waves are analyzed over the basin. Refer to the Special Features and Tropical Waves sections above for details. Aside from the convection associated with surface low and monsoon trough described above, heavy showers and tstms are N-NE of Dominican Republic to 21N supported by diffluence aloft and a tropical wave in the central Caribbean. A broad 1030 mb surface high is centered north of our area near 35N39W. The high continues to dominate the weather across the tropical north Atlantic. To the south of the high and away from the surface low described above, moderate to fresh trade winds prevail across the basin. This synoptic pattern will change little through the next couple of days. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos