000 AXPZ20 KNHC 201621 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Aug 20 2021 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...TROPICAL WAVES... A tropical wave extends from 02N to 15N with axis near 97W, moving W around 10 kt. Scattered moderate isolated strong convection is N of 08N between 92W and 101W. A tropical wave extends from 03N to 19N with axis near 113W, moving W at 10 kt. Scattered moderate isolated strong convection is from 11N to 14N between 106W and 116W. A tropical wave extends from 05N to 19N with axis near 126W, moving W at 10 kt. Scattered moderate isolated strong convection is from 10N to 15N between 121W and 126W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N73W to 08.5N87W to low pres near 16.5N104.5W 1007 mb to 11.5N120W to 13.5N140W. Aside from the convection described in the Tropical Waves section, scattered moderate isolated strong convection is N of 04.5N E of 101W, and within 120 nm of trough W of 128W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak pressure gradient across the region continues to support light to gentle NW to N winds along the Baja California offshore waters with seas ranging 5 to 7 ft. Light to gentle variable winds are elsewhere from Tehuantepec to the central Gulf of California with seas to 6 ft, except for 3 ft in the gulf. A surface trough along the northern Gulf of California supports moderate S to SW winds with seas 2 to 3 ft in that region. Similar conditions are forecast to remain in place through Sat. On Sat evening, winds across the Baja and SW Mexico offshore waters will increase to moderate to fresh ahead of the remnant low of Hurricane Grace, currently moving westward across the southwest Gulf of Mexico. Grace is forecast to move inland across central Mexico early tonight, and weaken as it continues westward across the mountainous terrain of central Mexico, then emerge over the eastern Pacific Ocean off the west-central coast of Mexico later on Sun. Environmental conditions are forecast to be conducive for development, and a tropical depression is likely to form late this weekend or early next week while the system moves westward away from the coast of Mexico. Regardless of development, strong winds and building seas will affect the offshore waters of Colima, Nayarit, and Baja California Sur Sun through Tue. Another area of low pressure is forecast to form off of the southwest coast of Mexico next week. Environmental conditions are expected to be conducive for some gradual development thereafter while the system moves west-northwestward near or just offshore the southwestern coast of Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Scattered showers and thunderstorms prevail across the offshore waters N of 04N, under the influence of moist monsoonal winds, the passage of tropical waves and Tropical Storm Grace, currently over the SW Gulf of Mexico. Light to gentle variable winds with seas to 6 ft are noted N of the monsoon trough while moderate to locally fresh S to SW winds are across the Costa Rica, Panama, Ecuador and Galapagos Islands offshore waters with seas 7 to 8 ft in long-period SW swell. Similar conditions will prevail through early next week, except for moderate to fresh NE to E winds forecast to pulse off the Gulf of Papagayo at night. REMAINDER OF THE AREA... Surface ridging continues over the NW forecast waters, centered on a 1034 mb high near 44N148W. The pressure gradient between the ridge and the Post-Tropical remnants of Linda, near 20.3N 144.0W at 1500 UTC, support moderate N to NE winds N of 18N and W of 125W. Seas of 6 to 9 ft in NE swell prevail across this area, except to 10 ft near 24N140W in the wake of Linda. Elsewhere, moderate to fresh SW winds are observed S of the monsoon trough with seas to 8 ft. Conditions associated with Linda will completely move W of the area today. Northerly swell will continue to propagate across the north-central waters and subside Sat night. Seas will be in the 8-9 ft range in that region. Otherwise, the remnants of current Hurricane Grace are forecast to emerge over the eastern Pacific Ocean off the west-central coast of Mexico on Sun. Environmental conditions are forecast to be conducive for development, and a tropical depression is likely to form late this weekend or early next week while the system moves westward away from the coast of Mexico. $$ Stripling