000 AXPZ20 KNHC 201606 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Sep 20 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 1500 UTC. ...TROPICAL WAVES... The axis of a tropical wave is along 101W and N of 06N, moving west at 10 to 15 kt. Scattered moderate convection is noted from 07N to 13N between 100W and 106W. The axis of a tropical wave is along 111W from 07N to 20N, moving west at 10 to 15 kt. Scattered moderate convection is seen from 14N to 20N between 106W and 114W. The axis of a tropical wave is along 123W from 07N to 17N, moving west at around 10 kt. Convection is limited near the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 11N100W a 1011 mb low pressure near 11.5N116W to 09N130W. The ITCZ continues from 09N130W to 06N140W. Aside from the convection associated with the tropical waves, scattered moderate convection is from 05N to 09N E of 85W to the coast of Colombia. A cluster of moderate convection is over the Gulf of Tehuantepec. Scattered moderate to isolated strong convection is noted from 08N to 12N between 112W and 120W. The latter convective activity is mainly associated with the above mentioned low pressure. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge dominates the offshore forecast waters of Baja California producing mainly gentle to moderate NW-N winds. Seas are in the 4-6 ft. Light to gentle winds are seen elsewhere offshore of SW Mexico with seas in the 3 to 5 ft range. Light SE-S winds prevail in the Gulf of California. Some shower activity is observed in parts of the central and southern Gulf of California and also near Los Cabos area. For the forecast, a ridge will continue to dominate the offshore waters of Baja California. Seas will build to 8 ft in NW swell N of Punta Eugenia tonight. A gap wind event is expected in the Gulf of Tehuantepec beginning late Tue night with gale conditions possible Wed to Thu night. Seas are forecast to build to 9 or 10 ft with this event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate southerly winds will prevail across the offshore waters of Costa Rica, Panama, Colombia and Ecuador during the forecast period with seas of 4-6 ft in SW swell. Mainly light and variable winds are forecast across the offshore waters from Guatemala to northern Costa Rica with seas of 3-5 ft also in SW swell. In the Papagayo region expect moderate NE-E winds through Tue. REMAINDER OF THE AREA... A weakening frontal boundary is located just N of area and extends from near the California/Baja California border to 30.5N128W. An altimeter pass indicates seas to 10 ft in the wake of the front. These seas will propagate across the northern forecast waters in NW swell trough late Tue or Tue evening. The northern forecast waters are under the influence of a ridge anchored by a 1028 mb high pressure located near 40N135W. Moderate to locally fresh trades are noted along the southern periphery of the ridge with seas of 5-7 ft based on altimeter data. An area of low pressure is forecast to form several hundred miles southwest of the southern tip of the Baja California peninsula within the next couple of days. Thereafter, some gradual development of this system is possible, and a tropical depression could form by the latter part of this week while it moves west-northwestward to northwestward at 10 to 15 mph. Regardless of development, winds may increase to fresh to strong with seas to around 9 ft on the E side of the low center. At 1200 UTC, a 1011 mb low pressure is analyzed along the monsoon trough near 11.5N116W. $$ GR