000 AXPZ20 KNHC 282127 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2034 UTC Sat Sep 28 2019 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Sixteen-E is centered near 15.0N 100.0W at 28/2100 UTC moving NW at 8 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. The system has been meandering during the day, but it should begin to move toward the northwest at 8 kt tonight. This motion is expected to continue during the next couple of days, bringing the disturbance or the cyclone very near or over the southwestern coast of Mexico. Some strengthening is forecast during the next 48 hours, and the disturbance is expected to become a tropical storm tonight or Sunday. However, if the center forms closer to the coast and interacts with the high terrain of Mexico, weakening should then occur. The system is expected to produce total rain accumulations of 3 to 7 inches with isolated maximum amounts of 15 inches along the southwestern coast of Mexico from Chiapas to Nayarit through Monday. This rainfall may cause life-threatening flash floods and mudslides, especially in mountainous terrain. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends along northern Central America and enters the eastern Pacific through the Gulf of Tehuantepec near 16N94W, then continues to 15N100W to 15N120W to 13N140W. Numerous moderate isolated strong convection is noted N of 12N between 93W and 98W, including the Gulf of Tehuantepec. Scattered moderate isolated strong convection is from 09N to 14N W of 130W, and within about 120 nm S of the monsoon trough between 120W and 130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Scatterometer data revealed gentle to moderate NW winds across the Baja California Norte offshore waters, while moderate to fresh NW winds were noted south of Cabo San Lazaro to Cabo San Lucas. Seas are running 5 to 7 ft across the Baja offshore waters in mixed NW and SW swell, except to 8 ft within the fresh flow between Cabo San Lucas and the Revillagigedo Islands. A weakening cold front offshore of southern California will dissipate today. A ridge will build into the region Sun through early next week and freshen NW winds over the Baja California Norte waters. Please see the Special Features section above for information about Potential Tropical Cyclone Sixteen-E. Strong SW to W winds prevail south of the monsoon trough over the southern Mexico offshore waters. Altimeter data showed 8-13 ft seas within this enhanced flow over the waters between Acapulco and Puerto Angel. Numerous showers and thunderstorms with strong gusty winds will continue off the southwestern coast of Mexico through Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough extends across the SW Caribbean Sea and northern Central America. Fresh SW to W monsoonal flow will continue to support scattered showers and thunderstorms across the offshore waters from Guatemala southward to Panama. Altimeter data indicated 8 to 10 ft seas across the waters off Guatemala and El Salvador, with 8 ft seas extending to the northern Costa Rica offshore waters. Seas 8-12 ft will persist off Guatemala and El Salvador into tonight, then remain 8 ft or greater through Mon before subsiding Mon night. REMAINDER OF THE AREA... Satellite wind data showed a small area of moderate to fresh NE winds roughly north of 26N and west of 135W. Seas in this region are running 8-10 ft in combined northerly swell and locally generated wind waves. Seas will gradually subside to 8 ft in this area on Sun. Elsewhere, high pressure located well NW of the forecast area is supporting light to gentle breezes, with 5 to 7 ft seas over much of the forecast region north of the monsoon trough W of 120W. Little change is expected through the weekend. South of the monsoon trough, moderate to locally fresh SW winds persist west of 125W with building seas to 8 or 9 ft. An area of low pressure is expected to form over the far southwestern portion of the eastern North Pacific early next week. Some gradual development is possible thereafter while the system drifts slowly eastward or northeastward. Currently, the Tropical Weather Outlook gives this system a low chance of tropical cyclone formation through 5 days. $$ GR