000 AXPZ20 KNHC 300712 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0710 UTC. ...TROPICAL WAVES... A tropical wave extends its axis along 85W/86W from the Caribbean coast of Nicaragua southward across Costa Rica into the eastern Pacific Ocean, moving slowly west at 5 to 10 kt. Associated convection is described below. A tropical wave that was previously along 115W/116W has become ill-defined at the surface and is no longer trackable at the surface. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N74W to 1010 mb low pressure near 08N91W to 11N97W, then resumes from 1011 mb low pressure near 16N106W to 1009 mb low pressure near 12N128W to 11N140W. Isolated to scattered moderate convection is noted from 04N to 07N between 81W and 85W, from 05N to 09N between 86W and 93W, from 15N to 17N between 97W and 102W, from 14N to 16N between 114W and 123W, from 10N to 16N between 124W and 130W, and from 09N to 14N between 133W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad area of low pressure is located a couple of hundred miles south-southwest of Manzanillo, Mexico with disorganized cloudiness and showers, and limited thunderstorm activity. Associated winds are mainly gentle, locally moderate, and nearby seas are 5 to 6 ft. Moderate NW winds are noted offshore of Baja California, while mainly gentle to moderate winds prevail elsewhere offshore of Mexico. NW swell is supporting seas of 7 to 11 ft west of Baja California, with the highest seas north of Punta Eugenia. Seas are mainly 4 to 6 ft elsewhere in mixed long period swell, except 3 ft or less in the Gulf of California north of the entrance area. For the forecast, any development of the broad area of low pressure during the next day or two should be slow to occur while it moves toward the west-northwest at 5 to 10 kt and reaches an area of stronger upper-level winds by Fri or Fri night. Moderate NW-N winds offshore of Baja California will diminish by the end of the week. 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 and 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... Light to gentle E-SE winds are noted north of the monsoon trough, with moderate S-SW winds south of the monsoon trough. Seas are mainly in the 4 to 6 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 12 ft north of 22N, while an area of 7 to 8 ft in fresh trades mixed with the swell is from 13N to 22N west of 124W. 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 later today 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