000 AXPZ20 KNHC 130900 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Sep 13 2023 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 0840 UTC. ...SPECIAL FEATURES... A tropical wave is along 129W from 04N to 16N, moving W at 10-15 kt. Scattered moderate isolated strong convection is noted from 03N to 16N between 118W and 138W. Fresh winds and seas to 8 ft are occurring with the tropical wave. Environmental conditions are conducive for development of this system, and a tropical depression is likely to form during the next few days while it moves west-northwestward to northwestward at 10-15 kt. By the weekend, upper-level winds are forecast to become less favorable for additional development while the system moves slowly westward. There is a medium chance of tropical cyclone formation within the next 48 hours. Winds with this system should increase to strong from tonight through the weekend, with seas forecast at 8-11 ft. Refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 10N100W. The ITCZ continues from 10N100W to 12N110W to 13N124W to 09N127W. The ITCZ continues west of the tropical wave from 08N132W to 04N140W. Aside from the convection mentioned above in the Special Features section, scattered moderate isolated strong convection is noted from 06N to 11N between 96W and 114W. Scattered moderate convection is from 01N to 05N between 138W and 140W, as well as near the coasts of Colombia, El Salvador and Guatemala. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge dominates the offshore forecast waters of Baja California. Recent ASCAT satellite data show mainly moderate NW to NNW winds to the west of Baja California, north of Cabo San Lazaro. To the south of Cabo San Lazaro, gentle WNW winds prevail. Seas are 5-7 ft to the west of Baja California Norte and 5-6 ft west of Baja California Sur. Mainly gentle S to SW winds and 1-3 ft seas are in the Gulf of California. Fresh N winds are in the Gulf of Tehuantepec with seas 6 to 8 ft. Light to gentle and variable winds prevail elsewhere with seas of 5-7 ft in long period S swell. For the forecast, fresh N gap winds will prevail in the Gulf of Tehuantepec through this morning. Mainly moderate to locally fresh NW to N winds are forecast over the waters west of Baja California through the upcoming weekend. Seas are expected to build to 6 to 7 ft off Baja California Sur with these winds. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Long period S to SW swell is affecting the waters offshore Central America and northern South America. N of 04N, winds are light to gentle, except for moderate E winds in the Papagayo region. South of 04N, recent ASCAT satellite data shows moderate to locally fresh southerly winds. Seas are 8-9 ft in between Ecuador and the Galapagos Islands based on altimeter data. Seas are 5-7 ft offshore Central America and Colombia, except up to 8 ft off southern Colombia, in long period S to SW swell. For the forecast, moderate to fresh southerly winds will prevail over the waters between Ecuador and the Galapagos Islands through Thu before diminishing late in the week. Seas of 8 to 9 ft in long period S to SW swell will continue over these waters through Thu or Thu night before subsiding. Elsewhere, light to gentle winds will prevail through Fri night, except for moderate NE to E winds in the Gulf of Papagayo through this morning. Long-period southerly swell, with seas of 6-7 ft, will continue to propagate across the offshore waters of Central America through tonight before gradually subsiding Thu and Thu night. ...REMAINDER OF THE AREA... A surface trough is along 135W from 18N to 26N. An area of fresh to strong NE winds remains between the northern end of the trough axis and a ridge to the N. Seas are 8 to 10 ft within these winds. Fresh winds and seas 7 to 8 ft are occurring in association with the aforementioned tropical wave along 129W. Moderate to locally fresh SE to S winds are south of 06N between 100W and 130W, where seas are 8-9 ft in long period S swell. S swell is reaching 8 ft as far north as 09N. Elsewhere, winds are moderate or weaker, with seas of 5-7 ft. For the forecast, the surface trough near 135W will drift west- southwestward until it moves west of 140W tonight. An area of fresh to strong winds between the trough and a high pressure to the N is forecast to persist through this morning. Elsewhere north of the ITCZ and E of 125W, mainly gentle to moderate NE to E winds will prevail. To the south of 09N and east of 128W, seas of 8 to 9 ft in long-period southerly swell will continue through this morning before gradually subsiding this afternoon through Thu night. $$ Hagen