000 AXPZ20 KNHC 232133 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2133 UTC Thu May 23 2019 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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 from Central America near 11N86W to 10N100W to 07N111W to 08N119W. The ITCZ continues from 08N119W to 06N130W to beyond 06N140W. Numerous moderate and scattered strong convection is noted from 08N to 13N between 94W and 99W. Scattered moderate and isolated strong convection is occurring from 03N to 07N between 83W and 86W, within 120 nm north of the monsoon trough between 102W and 106W, and within 90 nm south of the ITCZ between 137W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a high pressure ridge across the offshore waters west of Baja California and lower pressure over northern Mexico is supporting moderate to locally fresh NW winds near the west coast of Baja California. Recent scatterometer data highlighted an area of moderate winds between Punta Eugenia and Cabo San Lazaro. Altimeter data further offshore indicated seas are still running 8-12 ft in NW swell, with the highest seas over the outer waters north of Cabo San Lazaro. Winds are expected to diminish tonight into Fri as the pressure gradient relaxes, and decaying swell will allow seas to subside to 8 ft or less by Fri night. Gulf of California: Light to gentle breezes will prevail across the northern Gulf through Fri night with gentle to moderate winds over the central and southern Gulf. Looking ahead, SW gap winds across the northern Gulf will strengthen this weekend ahead of a cold front approaching the region. Expect strong to near gale force gap winds north of 29.5N Sat night into Sun with fresh winds persisting through Sun night. Wind speeds will diminish by early next week. Gulf of Tehuantepec: Fresh to strong northerly winds will pulse across the Gulf of Tehuantepec region during the overnight and early morning hours this weekend with the assistance of the nocturnal drainage flow. Seas will build to 8 ft with these short-lived gap wind events. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Showers and thunderstorms associated with a broad area of low pressure over Central America have become less organized since yesterday. Any development of this system during the next few days should be slow to occur while the large circulation interacts with land. Regardless of development, locally heavy rains are likely to continue over portions of Central America as this system remains nearly stationary through the weekend. These rains could cause flash flooding and mudslides in areas of mountainous terrain. The monsoon trough will dominate the regional pattern through early next week. The latest global model guidance suggests winds south of the monsoon trough will strengthen Mon through Tue, although wind speeds will be highly dependent on how the broad low pressure system over Central America evolves in the coming days. Seas will generally remain 8 ft or less through the weekend, then build into early next week in response to the strengthening monsoon flow. REMAINDER OF THE AREA... Northwest swell continues to impact the waters north of 20N between Baja California and 133W with 8-13 ft seas across the region based on recent altimeter data. This swell event will gradually decay through Fri with seas falling below 8 ft Fri night. A high pressure ridge extends from a 1034 mb high near 37N140W southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure near the ITCZ is maintaining fresh to locally strong trades over the waters west of 135W with seas up to 10 ft based on earlier altimeter data. Elsewhere, scatterometer data from earlier today showed an area of moderate to fresh W to SW winds south of the monsoon trough roughly between 92W and 98W. A small area of seas to 8 ft in mixed SW swell and wind waves persists along 08N between 94W and 100W based on recent altimeter passes. Farther south, a pulse of cross-equatorial SW swell is producing 8 ft seas over the waters south of the Equator and west of 108W. This swell will continue spreading northward through Fri. A stronger SW swell event is expected over the southern forecast waters Sun through early next week, mixing with wind waves generated by the monsoon circulation as the swell propagates northward. $$ Reinhart