348 AXNT20 KNHC 171003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Wed Aug 17 2022 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 0950 UTC. ...TROPICAL WAVES... A central Atlantic tropical wave has its axis near 43W, south of 20N, moving W at 15 o 20 knots. Isolated moderate convection is seen from 07N to 11.5N between 40W and 43W. Two tropical waves are located across the western Caribbean, one along 81W, moving W near 15 knots, and a second along 84W, moving W at 10 to 15 knots. Scattered to locally numerous moderate to strong convection is observed from 15N to 18.5N and between 81W and 87W. The associated moisture and wind field of these two waves are expected to merge during the next 24 hours as this feature moves across Central America, the Gulf of Honduras and into the Yucatan Peninsula Wed night. ...MONSOON TROUGH/ITCZ... The monsoon trough reaches the Atlantic through the coast of Mauritania near 10.5N16W to 08.5N30W to 11N40W to 07N49W. Scattered moderate to isolated strong convection is present from 04N to 15N and E of 25W. Scattered moderate to strong convection is noted from 06N to 13.5N E of 22W to the coast of Africa. Scattered moderate isolated strong convection is noted from 03.5N to 10N between 30W and 40W. GULF OF MEXICO... A weak high pressure regime continues to dominate the Gulf of Mexico, promoting fairly tranquil weather conditions across the basin. Moderate ENE-NE winds are found offshore NW and W Yucatan peninsula, while light to occasionally moderate anticyclonic winds are noted elsewhere. Seas of 3-4 ft are occurring across the eastern Bay of Campeche and W Gulf waters, while 1-3 ft prevail in the remainder of the Gulf. For the forecast, the weak high pressure centered across the SE Louisiana coastal waters will drift ESE in the north-central Gulf through tonight. A stalled front across the NE Gulf coast states will sink S and settle just north of the northern Gulf today and linger in this area through Thu. This will increase winds across the northeast and north- central Gulf with moderate westerly winds. A tropical wave currently located over Honduras and Nicaragua will move W across Central America through Thu and emerge over the Bay of Campeche Thu night, where an area of low pressure could form on Friday. Active weather and fresh easterly winds are expected to accompany this wave as it exits the Yucatan Penninsula into the Gulf. Some gradual development of this system is possible while it moves northwestward over the southwestern Gulf of Mexico through the weekend. CARIBBEAN SEA... Aside from the convection discussed in the Tropical Waves section, isolated showers and thunderstorms dot the waters north of 19N between the Windward Passage and Yucatan Channel. The rest of the basin enjoys tranquil weather conditions. A weak pressure gradient supports moderate or weaker easterly trade winds across the basin, except for locally fresh to strong trades off N Colombia and the Gulf of Venezuela, with fresh to local strong winds in the Gulf of Honduras. Seas are in the 3-5 ft range in the south- central Caribbean as well as in the Gulf of Honduras. Seas of 1-3 ft prevail elsewhere. For the forecast, the two tropical waves in the western Caribbean are expected to continue generating strong thunderstorms across NE portions of Honduras and Nicaragua and across the Gulf of Honduras. This active weather is expected to shift gradually westward with the tropical waves through Wed night. Weak 1015 mb high pressure is centered near 25N70W and yielding generally moderate trade winds across much of the basin. This high will strengthen modestly behind the exiting tropical waves tonight through Fri night to gradually bring a return of fresh to strong trade winds across the south-central basin. A tropical wave accompanied by a very broad surface trough will move across the Tropical Atlantic waters Thu night, across the eastern Caribbean Fri, and the central Caribbean Fri night and Sat. ATLANTIC OCEAN... Short lines of thunderstorms continue to develop across the NW waters early this morning, ahead of a frontal boundary off the SE United States coast. Gentle moderate SW winds are combining with divergent winds aloft sustain these lines of convection to the N of 28N between 67W and 79W. Farther south, a weak surface trough persists from Puerto Rico to 27N65W, and is interrupting the Atlantic ridge from extending further SW into the region, leaving a weak 1015 mb high centered near 25N70W. Scattered showers and thunderstorms are seen across the waters north of the Caribbean islands to 21N between 60W and 70W. The remainder of the tropical Atlantic is dominated by an expansive subtropical ridge positioned north of the Azores, maintaining tranquil weather conditions. Light to moderate anticyclonic winds and seas of 3-5 ft are found W of 55W. Gentle to locally fresh easterly trade winds and seas of 4-7 ft are noted between 22W and 55W. Fresh to strong NE winds and seas of 7-11 ft are present N of 18N and E of 22W, with the strongest winds and highest seas occurring off NW Mauritania and SE Western Sahara. Elsewhere, moderate or weaker winds and seas of 3-5 ft prevail. For the forecast W of 55W, the weak high pressure near 25N70W will collapse through tonight as the weak trough N of Puerto Rico drifts W. A stalled frontal boundary just NW of the area will drift SE to near the NE Florida waters today and linger across the region through Thu, which will maintain active weather N of 28N between Florida and 68W. High pressure will reestablish across the SW N Atlantic waters Wed night through Fri and lift northward Sat. $$ Stripling