000 AXPZ20 KNHC 192152 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed May 19 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends westward from 09N84W to 1010 mb low pressure 10N97W to 11N110W. The ITCZ continues from 11N110W to 10N125W to beyond 06N140W. Scattered moderate to isolated strong convection is noted near the low pressure from 09N to 11N between 95W and 100W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A recent scatterometer pass indicated generally moderate NW winds near the west coast of Baja California, except for moderate to fresh NW winds beyond 180 nm offshore. A concurrent altimeter pass indicated 5 to 7 ft seas. Mostly gentle breezes and slight seas prevail over the Gulf of California. Farther south, light to gentle W to NW winds and 5 to 7 ft seas in SW swell are noted. For the forecast, fresh NW winds will persist west of Baja California Norte through Sun. Seas will increase west of Baja California Thu night and Fri as NW swell behind a weak frontal boundary or trough moving across southern California and northern Baja California Norte. Meanwhile, long period SW swell will persist over Mexican offshore waters into the weekend. A tropical low may form well south of the Gulf of Tehuantepec region during the next day or two. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Recent scatterometer data shows light to gentle winds in the offshore waters of Central America and northwest South America. Concurrent altimeter satellite passes indicates seas are in the 5 to 7 ft range in most areas likely in SW swell. Seas are reaching 8 ft in Ecuadorian waters. For the forecast, long period cross-equatorial southerly swell will continue to impact the offshore forecast waters through Fri night, then begin to subside on Sat. Light to gentle winds are expected to continue through the weekend in the forecast waters. REMAINDER OF THE AREA... The subtropical ridge continues to dominate the waters north of 15N. The pressure gradient between it and comparatively lower pressure in the deep tropics supports a large area of moderate to fresh trade winds north of the ITCZ, with seas of 6 to 8 ft. Gentle to moderate trade winds are noted elsewhere. SW swell is evident farther east, with seas in excess of 8 ft reaching as far north as 10N east of 125W. A 1010 mb low pressure area is centered well south of Tehuantepec near 10N97W. Numerous showers and thunderstorms are ongoing near this low. An earlier scatterometer pass indicated fresh to locally strong winds are possible near low, with higher gusts to gale force possible through the afternoon. For the forecast, reinforcing high pressure will allow trade winds to increase north of the ITCZ and west of 125W, with seas building to around 8 ft. 8 to 10 ft seas west of Baja California will spread westward in the northern forecast waters Thu night through Sat morning. Seas will continue to be 6 to 7 ft east of 125W in SW swell. Looking ahead, the low pressure south of the Tehuantepec is not expected to intensify much as it tracks westward along 10N between 95W and 105W through early next week. $$ Christensen