812 AXNT20 KNHC 010517 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 117 AM EDT Sat Sep 1 2018 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 0515 UTC. ...SPECIAL FEATURE... Tropical Depression Six is centered near 14.2N 25.5W at 01/0300 UTC, or 70 nm WSW of The Southernmost Cabo Verde Islands, moving WNW at 12 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC for more details. ...TROPICAL WAVES... An Atlantic tropical wave extends its axis along 50W from 02N-13N, moving west at 15-20 kt. This position was based on satellite imagery and model guidance. Isolated showers are noted along the wave's axis. A central Caribbean tropical wave extends its axis from west Hispaniola near 20N73W to N Colombia near 09N75W, moving west at 10 kt. This wave was repositioned based on satellite imagery, low- level TPW imagery, and model guidance. This wave is in an area where an upper-level low prevails, centered near 17N74W. With these, scattered moderate convection prevails north of 17N between 67W-75W, affecting eastern Cuba, Windward Passage, Hispaniola, and the Mona Passage. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from W Africa near 18N15W to 17N18W, then resumes near 12N28W to 06N45W. See the Special Feature section for convection. In addition, scattered moderate convection is noted along the monsoon trough between 28W-44W. ...DISCUSSION... GULF OF MEXICO... An upper-level low is centered over SE Texas near 28N97W, and extends a trough across the western Gulf. At the surface, a trough extends from 28N95W to 27N90W. At this time, scattered showers are noted west of 90W. To the east, another upper-level low is developing near 27N87W. This feature is enhancing convection across the basin east of 90W. A surface trough was analyzed from 27N81W to 23N83W. Scattered showers are noted along the trough affecting southwest Florida. A 1022 mb high is centered over the W Atlantic near 33N69W. A surface ridge extend W from the high to E Texas along 30N. This ridge will dominate the Gulf waters into the weekend and support gentle to moderate SE winds. A surface trough will develop each evening in the Yucatan Peninsula. It will move W and offshore into the SW Gulf of Mexico during the overnight hours. A surge of moderate to fresh NE to E winds will accompany this trough each night. Furthermore, an upper-level low will advect from the N Bahamas to S Florida this weekend. Expect nocturnal thunderstorms over this area through this period. CARIBBEAN SEA... An upper-level low is centered south of Hispaniola near 17N73W. This enhancing convection over the island and adjacent waters, combined with a tropical wave described in the section above. To the south, the eastern part of the EPAC's monsoon trough is along 10N from Costa Rica to Colombia. Scattered showers are noted along the trough. Nocturnal winds will pulse to fresh to strong in the south central Caribbean during the next several nights. Gentle to moderate winds will prevail elsewhere. The tropical wave currently over Hispaniola, will move through the western Caribbean by late Sunday into early Monday with active weather. A second tropical wave will move into eastern Caribbean Sea by Sunday. ATLANTIC OCEAN... Refer to the sections above for information about the new T.D. Six and the tropical wave. An upper level low is centered north of the Bahamas near 29N77W. THis feature is enhancing scattered moderate convection west of 75W. To the east, a surface trough has broken away from the Caribbean's tropical wave and extends from 25N71W to 21N74W. Scattered moderate convection prevails along this trough affecting the southern Bahamas. This trough is moving WNW towards S Florida and the Gulf of Mexico. A 1022 mb high is centered over the W Atlantic near 33N68W. A surface trough is over the central Atlantic from 31N59W to 29N61W with no significant convection. A 1025 mb high is over the E Atlantic near 35N37W. With this, surface ridging prevails across most of the Atlantic waters. For additional information please visit http://www.hurricanes.gov/marine $$ ERA