000 AXPZ20 KNHC 150706 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Sep 15 2022 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 0600 UTC surface analysis and satellite imagery through 0700 UTC. ...SPECIAL FEATURES... Southwest of Southwestern Mexico: A 1007 mb low pressure system located a few hundred nautical miles southwest of Manzanillo, Mexico near 15.5N107.5W, continues to produce showers and thunderstorms, mainly to the west of its center of circulation. A band of scattered moderate to strong convection is noted between 120 nm and 240 nm in the western semicircle. Current winds are 20-30 kt with seas of 8-10 ft. Environmental conditions appear conducive for further development of this system, and a tropical depression is likely to form during the next couple of days while meandering southwest of the southwestern coast of Mexico. The latest Tropical Weather Outlook gives this system a high chance of tropical cyclone formation through 48 hours. A large area of disorganized showers and thunderstorms located a couple of hundred nautical miles off the coast of southern Mexico is associated with a broad 1009 mb area of low pressure near 12.5N96W. Scattered moderate to strong convection is noted over a broad area from 08N to 17N between 91W and 107W. Current winds are 20-25 kt with seas of 8-9 ft. Gradual development of this system is possible during the next couple of days or so, and a tropical depression could form before reaching the coast of southern or southwestern Mexico, and possibly moving inland, over the weekend. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone formation through 48 hours. Refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details on both areas. ...TROPICAL WAVES... The southern portion of a tropical wave extends along and just offshore western Colombia along 79W, north of 05N across Panama and into the Caribbean Sea, moving west at 5 to 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from northern Costa Rica near 10N86W to 1009 mb low pressure near 12.5N96W to 1007 mb low pressure near 15.5N107.5W to 12.5N120W to 1010 mb low pressure near 13.5N131.5W to 11N140W. Aside for the convection associated with the low pressure systems, scattered moderate and isolated strong convection is noted from 05N to 14N between 77W and 91W. Scattered moderate convection is noted from 06N to 10N between 130W and 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Refer to the Special Features section for details on two areas of low pressure near the outer offshore waters boundary. Gentle to moderate NW-N winds are offshore Baja California. Similar yet variable winds are across the remainder of the Mexico offshore waters, except fresh to locally strong offshore Oaxaca and Michoacan near the low pressures described above. Seas are mainly 5-7 ft in long period southerly swell across the open waters, and 1-3 ft in the Gulf of California north of the entrance. For the forecast, high pressure will build across the offshore waters of Baja California supporting moderate to fresh NW-N winds, locally strong near Punta Eugenia at night, and seas of 5-7 ft for the next few days. Gentle to occasionally moderate mainly southerly winds and 1-3 ft seas are expected in the Gulf of California. Marine conditions could deteriorate across the offshore waters between Oaxaca and Michoacan as the aforementioned low pressure systems develop, potentially then spreading west-northwest offshore southwestern Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate winds are noted north of the monsoon trough, while moderate fresh S-SW winds prevail south of the monsoon trough. Seas are 5-7 ft in SW swell across the offshore waters, with the exception of 6-8 ft between Ecuador and the Galapagos Islands, as well as well offshore Guatemala. A moist and unstable environment interacting with the monsoon trough persists across the area north of Ecuador resulting in showers and thunderstorms. For the forecast, mainly gentle to moderate winds will persist across the offshore forecast waters, with seas of 6-8 ft in SW swell. Winds could increase to moderate to fresh between northern Costa Rica and Guatemala toward the upcoming weekend as a broad area of low pressure develops along the monsoon trough. A very moist and unstable atmospheric environment will help maintain active weather across most of the offshore waters over the next few days. REMAINDER OF THE AREA... Refer to the Special Features section for details on two areas of low pressure near the outer offshore waters boundary of Mexico. High pressure dominates the waters north of the monsoon trough and west of about 120W. The related light pressure gradient is allowing for mostly light to gentle winds over the NW corner of the forecast area. Mainly gentle to moderate winds prevail elsewhere north of the monsoon trough. Seas are 5-7 ft, mainly in long period southerly swell. Moderate to locally fresh southerly winds prevail south of the monsoon trough along with 5-8 ft seas, outside of the low pressure areas described above. For the forecast, high pressure will build across the northern forecast waters over the next few days supporting gentle to moderate winds and seas of 4-7 ft. Winds will increase some between the ridge and transient low pressure located along the monsoon trough between 130W and 140W. Marine conditions could deteriorate east of 110W as the low pressure areas over the eastern waters try to develop. Additional pulses of cross- equatorial SW swell will continue to propagate across the forecast waters east of 110W. $$ Lewitsky