000 AXNT20 KNHC 040544 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 144 AM EDT Fri Aug 4 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...SPECIAL FEATURES... A large area of disturbed weather associated with a broad low pressure system extends from about 400 miles south of the Cabo Verde Islands. A 1013 mb surface low was analyzed near 10N23W. To the east of it, a tropical wave extends from 14N29W to a 1013 mb low near 09N28W to 05N27W. Scattered moderate convection is observed from 06N-11N between 21W-34W. Environmental conditions are forecast to be conducive for gradual consolidation and development, and a tropical depression is likely to form by early next week over the eastern or central tropical Atlantic Ocean. This system has a medium chance fro development within the next 48 hours. ...TROPICAL WAVES... A tropical wave extends its axis from 19N40W to 11N46W, moving west at 5-10 kt. The wave coincides with a sharp 700 mb troughing between 40W- 50W. The areal extent of the Saharan Air Layer across the central tropical Atlantic is inhibiting any significant convection with this wave at this time. A tropical wave extends its axis from 18N67W to a 1012 mb low near 12N67W to 10N67W, moving west at 5-10 kt. The wave continues moving within the southern periphery of a mid-level ridge anchored over the west Atlantic near 27N71W. Scattered moderate convection, likely enhanced due to ample upper level diffluence, is occurring from 09N-18N between 60W-70W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 17N16W to the Special Features lows, then to 06N45W. The Intertropical Convergence Zone extends from that point to 08N58W. Aside from convection associated with the tropical waves, no deep convection is observed at this time. ...DISCUSSION... GULF OF MEXICO... A middle to upper-level trough is noted on water vapor imagery over the lower Mississippi River valley this afternoon with the base of the trough extending over the NW Gulf waters. The troughing supports a surface trough that extends from SE Alabama to 30N91W to 27N97W. Low-level moisture convergence is maximized along this boundary with isolated showers occurring mainly north of 27N. The boundary is expected to drift eastward overnight with light to gentle anticyclonic winds expected to prevail on Friday. Elsewhere, a surface ridge extends across the southern Florida peninsula to the east-central coast of Mexico. Fair weather conditions are expected to persist with the ridge remaining in place across the basin through the weekend. CARIBBEAN SEA... A tropical wave is moving across the eastern Caribbean generating a broad area of scattered showers and thunderstorms generally east of 70W. Please refer to the section above for details. A surface trough was analyzed from 19N80W to 11N82W with isolated showers. Scatterometer data depicts moderate to fresh trades across the basin, with highest speeds near the tropical wave system. As the tropical wave along 67W moves westward, fresh to strong winds are expected to accompany the wave with continued convection through the weekend. ...HISPANIOLA... Scattered showers and thunderstorms are occurring across the southeastern adjacent coastal waters due to an approaching tropical wave currently located across the eastern Caribbean. The wave is expected to pass south of the island tonight and through Friday. Scattered showers and thunderstorms are expected through this period. ATLANTIC OCEAN... Two tropical waves are moving across the basin. Refer to the section above for details. A surface low is centered over the west Atlantic north of the area extending a surface trough from 31N80W to 28N80W. Isolated showers are noted in the vicinity of this feature. The remainder of the basin is under the influence of a surface ridge, anchored by a 1026 mb high centered near 29N56W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA