000 AXNT20 KNHC 210539 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 139 AM EDT THU JUL 21 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. ...TROPICAL WAVES... A tropical wave is moving across the east Tropical Atlantic with axis that extends from 21N21W to 11N21W, moving west near 10-15 kt over the past 12 hours. The wave coincides with a well defined 700 mb inverted trough as depicted in the global models and within a large surge of moisture as seen on the SSMI Total Precipitable Water imagery. Scattered moderate convection is observed across the southern portion of the wave mainly related to the Monsoon Trough S of 12N. A tropical wave is entering the E Caribbean with axis from 18N62W to 11N61W, moving west near 15-20 kt over the past 24 hours. The wave coincides with a weak 700 mb trough as depicted in the global models and within a surge of moisture as seen on the SSMI Total Precipitable Water imagery. Isolated convection is observed along this wave affecting the Lesser Antilles and Eastern Puerto Rico. A tropical wave is over the western Caribbean with axis from 23N80W to 13N81W, moving west near 20-25 kt over the past 24 hours. The wave coincides with a well defined 700 mb trough as depicted in the global models and moderate moisture prevails in its environment. No associated deep convection is observed at this time. A tropical wave is moving across southern Mexico and the EPAC with axis from 21N96W to 11N97W, moving west at 15 to 20 kt over the past 24 hours. The wave precedes a 700 mb trough as depicted in the global models and is embedded within a broad area of moisture as seen on the SSMI Total Precipitable Water imagery. Scattered showers and thunderstorms are from 12N-17N between 96W-101W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 19N16W and continues to 06N39W where the ITCZ begins and continues to South America near 03N51W. Scattered moderate to strong convection prevails across western Africa and south of the Monsoon Trough between 12W-22W while scattered moderate convection is along the same boundary between 29W-40W. ...DISCUSSION... GULF OF MEXICO... The northern portion of a tropical wave is enhancing convection across southern Mexico. Please see the section above for details. A surface ridge extends across the basin anchored by a 1020 mb high centered near 29N85W. With this, a gentle to moderate anticyclonic flow prevails across the northern half of the Gulf. An upper-level low centered over the Bay of Campeche is supporting isolated convection across the area mainly west of 94W. A surface trough has moved from the Yucatan Peninsula to the west extending from 22N91W to 19N92W. Expect during the next 24 hours for the surface ridge to persist across the basin. CARIBBEAN SEA... Two tropical waves are moving across the basin. Please refer to the section above for details. Isolated convection accompanies the tropical wave currently entering the east Caribbean affecting the Lesser Antilles and Puerto Rico and their adjacent waters north of 16N between 62W-67W. Scatterometer data depicts gentle to moderate trades across most of the Caribbean waters except between 70W-80W where moderate to fresh winds prevail due to a tight pressure gradient. Expect in 24 hours for the waves to continue moving west with enhancing convection. Little change is expected elsewhere. ...HISPANIOLA... Fair weather prevails across the island at this time. The passage of a tropical wave will support scattered moderate convection across the area within the next 24 hours. ATLANTIC OCEAN... A tropical wave is moving across the eastern Atlantic. Please see the section above for details. A surface trough extends across the western Atlantic from 29N76W to 27N79W with isolated convection. To the east, scattered moderate convection is approaching our area mainly north of 29N between 60W-70W as a cold front moves southeast. The remainder of the basin is dominated by a surface ridge anchored by a 1027 mb high centered near 34N45W. Expect for the surface trough over the west Atlantic to persist through Friday. The surface ridge over the west Atlantic will shift east ahead of the frontal boundary that will continue moving southeast while weakening. For additional information please visit http://www.hurricanes.gov/marine $$ ERA