000 AXPZ20 KNHC 182202 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Apr 18 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N78W to 03N110W. The ITCZ continues from 03N110W to 02N115W, and again from 01N130W to beyond 01N140W. Another ITCZ segment is farther south, extending from 01S90W to 03.4S115W. Scattered moderate convection is active from 04N to 08N between 83W and 88W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A pair of recent scatterometer satellite passes indicated moderate NW winds off the coast of Baja California. This is ahead of a weak cold front moving through southern California currently, which is disrupting the normal subtropical ridge over the region. Judging by nearby ship observations and buoy reports off southern California, wave heights as far south as Guadalupe Island may be reaching 8 ft this afternoon. This is the leading edge of a group of NW swell accompanying the front. Seas are likely 5 to 7 ft elsewhere off Baja California. Gentle breezes persist elsewhere over Mexican offshore waters, with 4 to 6 ft combined seas in open waters with a mix of NW and SW swell. For the forecast, the high pressure building behind the weakening cold front off California will support fresh to occasionally strong NW winds off Baja California north of Cabo San Lazaro through late Thu. Combined seas are expected to peak near 11 ft with NW swell offshore Baja Norte Wed morning. The front will dissipate through late Wed, and the high pressure will weaken and drift northwest Fri through Sat leading to a dimishing trend in winds and seas across the regional waters. Looking ahead, a new round of large NW swell may move into the waters off Baja California north of Punta Eugenia starting late Sat. Farther south, fresh to strong gap winds and rough seas may return to the Tehuantepec region by Sun. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Divergence aloft associated with an upper trough reaching from Florida southward through the Pacific coast of Nicaragua is supporting a small cluster of showers and thunderstorms from about 150 nm southwest of Costa Rica. High pressure north of the area is supporting fresh gap winds across the Gulf of Papagayo, and over the Gulf of Panama just east of the Azuero Peninsula. Light to gentle breezes are noted elsewhere. Combined seas are 4 to 6 ft in the Gulf of Papagayo and downstream, and mostly 2 to 4 ft elsewhere. For the forecast, the high pressure north of the area will support fresh to occasionally strong gap winds pulses through mid week across the Gulf of Papagayo and the coast of Nicaragua. Moderate winds in the Gulf of Panama will briefly pulse to fresh tonight and Wed night. Elsewhere, light to gentle variable winds and moderate seas in SW swell will prevail. ...REMAINDER OF THE AREA... Recent buoy data and scatterometer satellite data showed moderate to locally fresh NE trade winds from 05N to 15N west of 120W, between a trough in the deep tropics between 120W and 130W and the subtropical ridge north of 20N. Recent altimeter satellite data confirmed combined seas in this area are 7 to 8 ft mixed NE and NW swell. Scattered thunderstorms near the surface trough have diminished significantly in recent hours. Gentle to moderate winds are noted elsewhere to the north, where seas of 5 to 7 ft prevail. For the forecast, winds and seas over the tropical Pacific west of 125W will gradually diminish through mid week as high pressure weakens north of the area. New longer period NW swell in excess of 8 ft will move into the waters north of 20N through Wed, with highest seas reaching 12 ft along 30N120W. For Thu through Sat, combined seas of 8 to 9 ft will persist north of 25N and east of 125W to near the Baja California coast. Seas associated with fresh trade winds in NW swell will persist from 05N to 20N west of 125W. $$ Christensen