000
AXPZ20 KNHC 191552
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The monsoon trough extends westward from 11N85W to 11N110W. The 
ITCZ continues from 11N110W to beyond 08N140W. Scattered 
moderate convection is noted from 06N to 11N between 92W and 
88W. Scattered moderate to isolated strong convection is evident
from 09N to 12N between 118W and 128W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Several ship observations indicate mostly fresh fresh NW winds 
near the west coast of Baja California, with 6 to 8 ft seas. 
Light winds 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 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...

Earlier scatterometer data showed light to gentle winds in the
offshore waters of Central America and northwest South America.
Concurrent altimeter satellite passes indicated seas are in the 
6-8 ft range, likely in SW swell. 

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. 

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, weak low pressure is expected 
to form well south of the Tehuantepec area by Thu, but not 
intensify as it tracks westward along 10N between 95W and 105W 
through Sun.

$$
Christensen