000 AXPZ20 KNHC 211541 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Aug 21 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. ...SPECIAL FEATURES... Tropical Storm Grace is centered over eastern Mexico near 19.7N 98.9W at 21/1500 UTC moving WSW at 11 kt. Estimated minimum central pressure is 990 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Grace is forecast to dissipate today. However, Grace's remnants are expected to continue moving westward and emerge over the eastern Pacific Ocean off the west- central coast of Mexico by Sunday afternoon. Environmental conditions are forecast to be conducive for development, and a tropical depression is likely to form by early next week while the system moves westward at 10 to 15 kt away from the coast of Mexico. There is a high chance of tropical cyclone formation of this system within the next 5 days. Refer to the National Hurricane Center Tropical Weather Outlook for more details. ...TROPICAL WAVES... A tropical wave extends from 01N to 15N with axis near 103W, moving W at 5 to 10 kt. Scattered moderate convection is N of 10N between 97W and 105W. A tropical wave extends from 01N to 19N with axis near 117W, moving W at 5 to 10 kt. Scattered moderate convection is from 11N to 15N between 110W and 120W. A tropical wave extends from 01N to 18N with axis near 130W, moving W at 5 to 10 kt. Scattered showers are noted along 12N where the wave meets the monsoon trough. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 11N94W, then resumes near 15N104W to low pres near 10N122W 1006 mb to 12N137W. Aside from the convection described in the Tropical Waves section above, scattered moderate convection prevails from 05N to 08N between 82W and 105W, and from 07N to 13N between 110W and 130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Refer to the section above for details on the Special Feature system that will develop from the remnants of T.S. Grace. Recent scatterometer data confirm gentle to moderate NW to N winds along the Baja California offshore waters, and SW to W winds of similar magnitude in the Guerrero and Colima offshore waters. Seas in these areas remain between 5 to 7 ft. Moderate to locally fresh S to SW winds continue in the northern Gulf of California being supported by a surface trough. Light to gentle variable winds are elsewhere. Similar conditions are forecast to remain in place through today. By tonight, winds across the Baja California and SW Mexico offshore waters will increase to moderate to fresh ahead of the remnant low Grace. The remnants of Grace will emerge over the eastern Pacific Ocean off the west-central coast of Mexico on Sun afternoon. Regardless of development, strong winds and building seas will affect the offshore waters of Colima, Nayarit, and Baja California Sur from Sun through Tue. Another area of low pressure is forecast to form offshore of the coast of southern Mexico early next week. Environmental conditions are expected to be conducive for some gradual development thereafter, and a tropical depression could form by the middle of next week. The system is forecast to move generally west-northwestward near or just offshore of 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 05N, under the influence of moist monsoonal winds aided by Grace over SE Mexico, and the passage of tropical waves. 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 between 6 to 8 ft in long- period SW swell. Similar marine conditions will prevail through the middle of next week, except for moderate NE to E winds forecast to pulse off the Gulf of Papagayo through Mon. REMAINDER OF THE AREA... Surface ridging continues over the NW forecast waters, centered on a 1031 mb high near 45N149W. The pressure gradient between the ridge, and the remnants of Linda over the central Pacific continue to support moderate N to NE winds N of 15N and W of 125W. Seas of 6 to 9 ft in NE swell prevail across this area. Elsewhere, moderate to fresh SW winds are observed S of the monsoon trough with seas in the 8 to 10 ft range. Northerly swell will continue to propagate across the north- central waters and subside tonight. Seas will be in the 8-9 ft range in that region. Otherwise, the ridge centered well NW of the area will maintain a modest gradient across the western waters, with moderate N to NE winds persisting north of the monsoon trough and west of 125W through the middle of next week. $$ ERA