000 AXNT20 KNHC 211044 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 644 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 0600 UTC surface analysis and satellite imagery through 1030 UTC. ...TROPICAL WAVES... A tropical wave is moving across the east Tropical Atlantic with axis that extends from 21N24W to 10N23W, moving west near 10-15 kt over the past 18 hours. The wave coincides with a 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 10N. A tropical wave is moving across the E Caribbean with axis from 19N66W to 10N63W, 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 the northern portion of the wave affecting the Leeward Islands and Eastern Puerto Rico. A tropical wave is over the western Caribbean with axis from 23N82W to 12N83W, 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. Isolated showers are observed over the northern portion of the wave mainly north of 20N between 80W-84W. A tropical wave is moving across southern Mexico and the EPAC with axis from 21N97W to 11N98W, moving west at 10-15 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 13N-17N between 96W-101W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 17N16W and continues to 07N37W where the ITCZ begins and continues to South America near 00N49W. Scattered moderate convection prevails within 100 nm on either side of the Monsoon Trough. ...DISCUSSION... GULF OF MEXICO... The northern portion of a tropical wave is enhancing convection across south-central Mexico. Please see the section above for details. A surface ridge extends across the basin anchored by a 1020 mb high centered near 30N87W. 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 95W. A surface trough has moved from the Yucatan Peninsula to the west extending from 22N92W to 19N93W. A diffluent flow aloft is supporting scattered moderate convection across the southeast Gulf affecting the Florida Straits and southern portion of the peninsula south of 26N and east of 85W. 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 over the eastern Caribbean affecting the Leeward Islands and Puerto Rico as well as their adjacent waters north of 16N between 63W-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 31N76W to 27N79W with isolated convection. The proximity of this feature combined with a diffluent flow aloft is supporting scattered showers and thunderstorms south of 27N between 77W-80W. To the east, isolated showers are approaching our area mainly north of 29N between 59W-69W 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 36N41W. 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