000 AXPZ20 KNHC 300219 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Sep 30 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 0000 UTC surface analysis and satellite imagery through 0130 UTC. ...TROPICAL WAVES... A tropical wave extends its axis along 84W from the Caribbean coast of Nicaragua southward across Costa Rica into the eastern Pacific Ocean, moving west at around 10 kt. Associated convection is described below. A tropical wave has its axis along 115W from 06N to 18N, moving west at around 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N76W to 10N86W to 1010 mb low pressure near 08N91W to 10N97W, then resumes from 17N102W to 1011 mb low pressure near 16N106W to 1008 mb low pressure near 12N127W to 11N140W. Isolated to scattered moderate convection is noted from 01N to 09N between 80W and 86W, within 150 nm southwest of a line from 10N96W to 07N87W, and from 09N to 16N between 120W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad low pressure system located a few hundred miles south of Manzanillo, Mexico, is producing disorganized showers and a few thunderstorms, and environmental conditions are only marginally conducive for development. Associated winds are locally moderate, and seas are 5 to 6 ft. Moderate to locally fresh winds are noted offshore of Baja California with the strongest near Punta Eugenia. Mainly gentle to moderate winds prevail elsewhere offshore of Mexico. NW swell is supporting seas of 7 to 10 ft west of Baja California Norte. Seas are mainly 4 to 6 ft elsewhere in mixed long period swell, 2 to 4 ft in the Gulf of California except 3 ft or less in the central portion. For the forecast, the broad low pressure is forecast to meander off the coast of southwestern Mexico through tonight, and then move slowly WNW at about 5 kt away from the coast of Mexico by the end of the week. Moderate NW-N winds offshore of Baja California will diminish by the end of the week. Moderate to fresh southerly winds in the northern Gulf of California will diminish on Thu. Moderate to fresh gap winds may develop in the Gulf of Tehuantepec this weekend, increasing to fresh to strong Sun night. Otherwise, light to gentle winds will prevail. Large NW swell propagating southeast offshore of Baja California will subside by the end of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate NE-E winds are noted in the Papagayo region, with light to gentle winds elsewhere north of the monsoon trough. Moderate S-SW winds prevail south of the monsoon trough. Seas are mainly in the 5 to 7 ft range in mixed long period mixed swell. For the forecast, winds in the Papagayo region will occasionally pulse to moderate at nighttime. Otherwise, light to gentle winds will prevail north of the monsoon trough, with mainly moderate S-SW winds south of the monsoon trough. A moderate cross- equatorial SW swell will propagate through the regional waters during the next several days. REMAINDER OF THE AREA... High pressure prevails across the remainder of the basin. A set of NW-N swell supports seas of 8 to 11 ft north of 23N, while an area of 7 to 8 ft in fresh trades mixed with the swell is from 14N to 23N west of 125W. Seas are mainly 5 to 7 ft across the remainder of the open waters. Mainly moderate to locally fresh trades prevail elsewhere north of the convergence zone, with moderate southerly flow south of the monsoon trough. For the forecast, the NW-N swell will continue to propagate through the northern and central waters through late Thu while gradually decaying. Reinforcing fresh northerly swell will pump seas back up to around 8 ft near 30N between 125W and 135W into the weekend. Trades are forecast to diminish this weekend into early next week as the pressure gradient loosens. $$ Lewitsky