391 AXNT20 KNHC 221205 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 AM EDT Wed Aug 22 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 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 24W/25W from 05N-20N, moving westward at 10-15 kt. The wave is embedded within a very dry and stable environment inhibiting convection at this time. A central Atlantic tropical wave has its axis extending along 44W from 05N-19N, moving westward at 10-15 kt. This wave is also embedded within a very dry and stable environment caused by Saharan Air Layer outbreak migrating westward across the central and eastern Atlantic. Isolated showers and thunderstorms are within 120 nm either side of the wave from 09N to 11N. An eastern Caribbean Sea tropical wave has its axis along 64W from 07N-19N, moving westward near 10-15 kt. Scattered showers and isolated thunderstorms are east of the wave from 11N to 13N. A central Caribbean tropical wave has its axis along 74W/75W from 09N to 20N, moving westward near 15 kt. Scattered moderate convection is between eastern Cuba and Jamaica, and over some sections of northern Colombia. The tropical wave that move inland the Yucatan Peninsula yesterday is approaching 92W, with its northern extent reaching near 20N. It is moving westward near 15 kt. Previous numerous showers and thunderstorms observed over the western Yucatan Peninsula have diminished to isolated showers and thunderstorms. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the African coast near 17N16W to 11N24W to 10N34W to 06N42W. The ITCZ axis begins at 06N45W to 08N53W to 09N61W. Scattered moderate convection is within 180 nm north of the ITCZ axis between 46W and 53W. Isolated moderate convection is within 120 nm north of the monsoon trough axis between 29W and 34W. ...DISCUSSION... GULF OF MEXICO... Weak ridging extends across the northern Gulf of Mexico along 26N anchored by a 1019 mb high centered near 26N92W. This is maintaining light to gentle breezes and 1 to 3 ft seas. Gentle to moderate easterly flow is noted elsewhere south of the ridge. Scattered showers and thunderstorms are observed over the far southwest section of the gulf south of 21N and west of 94W in association with a trough that moved offshore the Yucatan Peninsula during the overnight hours. This activity is expected to remain active during the morning before weakening during the afternoon. It should then reform tonight and Thu night as the surface trough again moves across those same waters. Relatively weak high pressure ridging will remain across the northern gulf waters, with the associated gradient producing gentle to moderate anticyclonic flow through Fri. CARIBBEAN SEA... Two tropical waves are moving across the basin. Refer to the section above for details. An upper level trough extends across the west Caribbean enhancing convection across Cuba and adjacent waters north of 18N and west of 75W. The pressure gradient across the area will maintain fresh to strong winds over the south central Caribbean off the coast of Colombia and across the Gulf of Venezuela through Thursday. Moderate to fresh trades will continue elsewhere through this period also. Little change is expected with the present synoptic set-up through Fri. ATLANTIC OCEAN... Over the western Atlantic, a surface trough is analyzed from near 28N78W to 25N79W. Isolated showers and thunderstorms are noted near this trough affecting the northern Bahamas. Two tropical waves are moving across the basin. Refer to the section above for details. Another trough extends along 51W from 21N to 30N. No deep convection is noted with this trough. A 1025 mb high center is analyzed north of 31N and extends a ridge across the remainder of the basin. The trough extending across the central Bahamas will continue westward during today. Another trough extends from 28N61W to 21N67W. Scattered showers and thunderstorms are seen from 24N to 28N between 62W and 70W. Expect foe this activity to continue through tonight. Saharan dust and associated dry air, as also mentioned above under Tropical Waves, is noted mainly east of about 60W on GOES-16 Saharan Air Layer animation is inhibiting convection from developing across the eastern and central Atlantic waters. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre