000 AXNT20 KNHC 061114 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 713 AM EDT Thu Jul 6 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...SPECIAL FEATURES... Tropical Depression Four is centered near 13.2N 40.0W at 06/0900 UTC or about 1250 nm east of the Lesser Antilles moving WNW at 15 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. Scattered moderate and isolated strong convection is located within 120 nm of the center of the depression, primarily in the western semicircle. Please see the latest NHC Public Advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...TROPICAL WAVES... A new tropical wave was introduced on the 06 UTC map, just exiting the west African coast. This was evident from the SUNY-Albany Trough Diagnostics at 700 mb as well as conventional satellite imagery. No significant deep convection is currently associated with the wave. A tropical wave over the central Atlantic has an axis near 58W extending from 07N to 20N, moving west at about 15 kt during the last 24 hours. The wave is easily identifiable both at 700 mb through the Trough Diagnostics and the Lesser Antilles rawindsondes and observations at the surface. However, the wave is in a region of abundant Saharan dry air and dust that is currently hindering convection. Isolated moderate convection and scattered showers are present within 120 nm of the wave axis south of 13N. A tropical wave located over the central Caribbean has an axis near 78W extending from 10N to 22N, moving west at around 15 kt during the past 24 hours. The wave is easily identifiable both at 700 mb from the Kingston and San Andres rawindsondes and at the surface. Abundant moisture is associated with this wave as seen in the Total Precipitable Water imagery. However, no deep convection is currently associated with this wave. A tropical wave is moving across the Yucatan Peninsula with axis near 94W extending from 12N to 22N, moving westward at about 15 kt. The wave is easily identifiable both at 700 mb from the Mexico and Belize rawindsondes and at the surface. Scattered moderate and isolated strong convection is occurring over portions of the Yucatan and southeastern Mexico, due to the interaction of the wave with a tropical upper tropospheric trough over the Gulf of Mexico. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from 14N17W to 13N37W. The Intertropical Convergence Zone extends from 12N41W to 10N53W. Aside from the convection related to Tropical Depression Four, widely scattered showers are observed in the vicinity of the ITCZ mainly south of 08N between 40W-50W. ...DISCUSSION... GULF OF MEXICO... A weak surface ridge extends across the northern Gulf of Mexico. A tropical wave extends across eastern Mexico into the southwestern Gulf of Mexico enhancing showers and convection in this area. Refer to the Special Features section above for details. A light to moderate anticyclonic breeze prevails across the Gulf. Little change in this pattern is expected during the next couple of days. CARIBBEAN SEA... A tropical wave is moving across the 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 moderate to fresh tradewinds over the basin, except over the waters north of Colombia and Venezuela where strong breeze easterlies are pulsing every night lasting through the early morning hours. The ASCAT scatterometer data at 0246 UTC showed a widespread area of 25 kt winds. Little change is expected through Friday morning, but with diminishing winds Friday night. ...HISPANIOLA... A tropical wave is located to the west of Hispaniola enhancing scattered showers over portions of the island this evening. Additional moderate convection over the island is possible later today especially with the diurnal heating in the afternoon, before some drying occurs on Friday as the wave continues moving west. ATLANTIC OCEAN... Tropical Depression Four and two tropical waves were analyzed over the tropical North Atlantic. Refer to the Special Features and Tropical Waves sections above for details. Aside from the convection associated with Tropical Depression Four and the ITCZ previously mentioned, no other significant convection is occurring. A broad 1029 mb surface high is centered north of our area near 36N35W. This high continues to dominate the weather across the area. To the south of the high and away from Tropical Depression Four 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 $$ Landsea