611 AXNT20 KNHC 230527 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 127 AM EDT Thu Aug 23 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. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 29W from 07N-20N, moving westward at 10-15 kt. The wave is embedded within a very dry and stable environment which is inhibiting convection at this time. A central Atlantic tropical wave has its axis extending along 48W from 06N-20N, moving westward at 10-15 kt. This wave is also embedded within a very dry and stable environment caused by Saharan Air Layer outbreak of the past several days that is spreading westward across the central and eastern Atlantic. Scattered showers are noted south of 10N where the wave meets the ITCZ. An eastern Caribbean Sea tropical wave has its axis along 69W south of 20N to well inland Venezuela. It is moving westward near 10-15 kt. No significant convection is observed within this wave at this time. A west Caribbean tropical wave has its axis along 82W from 05N- 20N, moving westward near 10-15 kt. Scattered showers prevail south of 12N between 80W-85W. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the African coast near 14N17W to 10N22W to 07N36W. The ITCZ axis begins at 07N36W and continues to 08N44W, then resumes west of a tropical wave near 09N50W to 10N58W. Scattered showers are noted along the ITCZ and within 75 nm on either side of the monsoon trough mainly east of 20W. ...DISCUSSION... GULF OF MEXICO... A 1018 mb surface high is centered near 27N93W. To the east, a pre-frontal trough extends along 28N between 85W-89W. The cold front remains over land at this time, extending from the Florida Panhandle to 30N89W. Scattered showers are observed over northern Florida in the vicinity of the front. The nocturnal Yucatan Peninsula trough is developing, with scattered moderate convection prevailing over land. This convection is expected to reach the Bay of Campeche overnight, and dissipate as the day progresses. The present pressure gradient across the gulf supports light to gentle winds throughout, except for gentle to moderate winds south of 26N and relatively low seas of 1 to 3 ft. Expect for the relatively weak high pressure ridging to remain across the northern gulf waters, with the associated gradient producing gentle to moderate anticyclonic flow through the end of the week. The front will reach the northeast gulf waters, then dissipate quickly. CARIBBEAN SEA... Two tropical waves are moving across the basin. Refer to the section above for details. An upper level trough extends from eastern Cuba southwestward to just east of northeastern Honduras. Water vapor imagery indicates plentiful moisture along and to the northwest of this trough, and it is where scattered showers are occurring. Scattered showers are also occurring over the southwestern Caribbean south of 12N between 80W-85W due to the interaction of a tropical wave, low-level wind speed convergence, and the eastern segment of the eastern Pacific monsoon trough that stretches east- northeastward to the far southwestern Caribbean along 09N. A slighter tighter pressure gradient behind the tropical wave along 82W will help induce strong to near gale force northeast to east trade winds over the south-central Caribbean waters off the coast of Colombia and across the Gulf of Venezuela overnight. The strong trades are forecast to reach northward to 15N. Moderate to fresh trades will continue elsewhere through Fri, as little overall changes are expected with the present synoptic set-up through that period. ATLANTIC OCEAN... Two tropical waves are moving across the basin. Refer to the section above for details. A surface trough is analyzed from 25N79W to 23N80W. Another trough extends from 29N66W to 26N69W. A third surface trough is located from 27N54W to 22N55W. None of these features have significant convection at this time. A 1025 mb high center is analyzed north of 31N and extends a ridge across the remainder of the basin. Saharan dust and associated dry air, although not as dense as in previous days, is noted mainly east of about 60W on GOES-16 GEO color dust imagery. The dust is keeping convection limited to non- existent across the eastern and central Atlantic waters. For additional information please visit http://www.hurricanes.gov/marine $$ ERA