580 AXNT20 KNHC 231705 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 105 PM EDT Mon Jul 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 |1200 UTC surface analysis and satellite imagery through 1715 UTC. ...TROPICAL WAVES... A tropical wave is moving across the far east Atlantic with axis extending from 05N-20N along 29W, moving W at 10-15 kt. A large area of Saharan dust is noted along the wave mainly north of 10N. Widely scattered moderate convection is noted where the tropical wave intersects the monsoon trough from 08N-11N between 22W-29W. A tropical wave is in the central Atlantic with axis extending from 06N-22N along 48W, moving W at 10-15 kt. This tropical wave continues to be on the leading edge of a large area of Saharan dry air and dust, inhibiting large scale convection at this time. Scattered moderate convection is noted on the southern end of the tropical wave where it intersects the monsoon trough from 05N- 09N between 40W-47W. A tropical wave is in the western tropical Atlantic with axis extending from 10N-24N along 60W, moving W at 10-15 kt. The tropical wave is accompanied by Saharan dry air and dust, inhibiting convection. Scattered showers are over the Leeward Islands. A low amplitude and low latitude tropical wave is moving across Costa Rica and adjacent waters, along 83W and south of 11N. The tropical wave may be interacting with monsoon flow over Costa Rica and Panama. Scattered moderate to isolated strong convection is from 07N-11N between 76W-86W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 15N17W to 10N23W to 08N36W. The ITCZ extends from 08N36W to the coast of South America near 07N58W. Besides the convection mentioned in the tropical wave section, scattered showers are within 120 nm of the remainder of the monsoon and ITCZ axis. ...DISCUSSION... GULF OF MEXICO... A cold front extends from the Florida Panhandle at 30N84W to beyond SE Louisiana at 30N89W, with scattered moderate to isolated strong convection from 26N-30N between 82W-89W. A squall line is along the forward extent of the convection from Tampa Florida at 28N83W to 26N87W. 20-30 kt winds and 7 ft seas are being reported along the squall line. The remainder of the basin is under the influence of a surface ridge, anchored by a 1016 mb high centered over the Yucatan Channel near 21N85W. This feature is maintaining fair weather, light to gentle winds, and 1 to 3 ft seas across remainder of the basin. The cold front over the Florida Panhandle will be followed by another weak cold front that will move over the northern Gulf waters early this week. This front will become stationary and weaken Thu. A surface trough will move off the Yucatan Peninsula into the Bay of Campeche each evening, accompanied by fresh nocturnal winds. Elsewhere, surface ridging will prevail. CARIBBEAN SEA... The northern portion of a tropical wave is moving across the far southwestern Caribbean today, just north of Costa Rica. Another tropical wave is entering the E Caribbean. See above. Widely scattered moderate convection is S of Cuba from 18N-20N between 76W-82W. Dry conditions persist elsewhere. Earlier scatterometer pass indicated fresh to strong trade winds over the south central Caribbean, mainly off Colombia. Maximum seas are estimated to be 8 to 9 ft. Seas are 2 to 3 ft in the northwest Caribbean, and 5 to 7 ft elsewhere. ATLANTIC OCEAN... Two more tropical waves are moving across the basin. Refer to the section above for details. Scattered moderate to isolated strong convection is over the northern Bahamas and adjacent waters from 23N-26N between 77W-80W, related to divergent flow aloft. Gusty winds are possible with these thunderstorms. Moderate S to SW winds are noted west of 70W with 4 to 6 ft seas in open waters. A broad high prevails across the remainder of the basin, centered near 40N48W. For the forecast, the Atlantic high pressure along with the low pressure system over the southeast U.S. will continue to produce moderate to fresh southerly winds across the waters just offshore the central and northeast Florida through Wed. Moderate to fresh winds are also expected south of 22N, including approaches to the Windward Passage. Ridging will dominate the area most of the forecast period, with a surface trough reaching the E part of the region by Thu. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa