AXPZ20 KNHC 222128

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2128 UTC Wed May 22 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.


The monsoon trough extends from the coast of Costa Rica near 10N85W to 1009 mb low pressure near 10.5N88W to 12N94W to 09N110W to 07N115W to 07N127W. The ITCZ continues from 07N127W to beyond 05N140W. Scattered moderate and isolated strong convection is occurring within 150 nm S semicircle of the low center. Scattered moderate convection is noted from 06N to 11N between 100W and 107W.



A high pressure ridge extends SE into the offshore waters west of Baja California. The pressure gradient between the ridge and lower pressure across the SW United States and Mexico is supporting moderate to fresh NW winds roughly north of 27N and east of 123W per recent scatterometer data. Seas in this region are generally running 9-12 ft in NW swell with the highest seas west of Baja California Norte. Wind speeds are expected to diminish through Thu, but seas will remain up to 12 ft in NW swell west of Guadalupe Island through Thu morning. Seas greater than 8 ft will continue to affect the area through Fri night.

Elsewhere, scatterometer data revealed fresh NW winds west of Cabo San Lucas off the southern coast of Baja California Sur. These winds will likely persist tonight before diminishing on Thu as well.

Gulf of California: Strong SW to W gap winds are likely ongoing over the Gulf of California north of 29.5N. These winds will reach near gale force speeds overnight with seas building to 8 ft as the tail end of a cold front moves across the northern Gulf. Wind speeds will quickly diminish on Thu as the pressure gradient relaxes over the region. Looking ahead, another strong SW gap wind event is expected Sat night into Sun ahead of another cold front approaching the region.

Gulf of Tehuantepec: Fresh to strong northerly winds will pulse across the Gulf of Tehuantepec this weekend. Seas will build to 8-9 ft within the strongest winds during the overnight and early morning hours.


An area of low pressure located just off the west coast of Nicaragua continues to produce disorganized showers and thunderstorms. This system is expected to meander over the far eastern North Pacific, and gradual development is possible during the next several days if the disturbance remains offshore. Regardless of development, this system is likely to produce locally heavy rains over portions of Central America during the next few days. These rains could cause flash flooding and mudslides in areas of mountainous terrain.

Elsewhere, light to gentle winds will persist north of the monsoon trough, with gentle to moderate S to SW winds south of the monsoon trough over the next several days. Generally 5-7 ft seas in SW swell are expected through at least Fri.


A high pressure ridge extends from a 1032 mb high near 39N138W east-southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge and the ITCZ supports fresh trades from 14N to 23N west of 130W based on scatterometer data from this afternoon. A 1740 UTC altimeter pass revealed a swath of 7-9 ft combined seas extending from 30N133W to 10N131W, likely in mixed SW and NW swell and NE wind waves. Elsewhere, a small area of 8 ft seas is likely located from 06N to 09N near 105W based on earlier altimeter data. Farther south, a pulse of cross-equatorial SW swell will result in 8 ft seas developing by Thu over the waters generally south of the Equator and west of 100W.

$$ Reinhart