000
AXPZ20 KNHC 190255
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 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 0000 UTC surface analysis and satellite imagery through
0230 UTC.

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

The monsoon trough extends westward from 09N78W to 09N110W. The 
ITCZ continues from 09N110W to 08N125W to 09N140W. Scattered 
moderate isolated strong convection is noted from 06N to 10N
between 88W and 94W. Scattered moderate convection is evident
from 06N to 10N between 113W and 129W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Recent scatterometer data shows moderate to fresh NW winds near
the west coast of Baja California. Altimeter data indicates seas
are 6-7 ft west of Baja California. 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 reaches the area. 
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 later this week.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and 
WITHIN 750 NM OF ECUADOR...

Recent scatterometer data shows light to gentle winds across the
forecast waters, and altimeter satellite passes indicate seas are
in the 6-8 ft range, in SW swell. The upper level pattern is 
supporting a few showers and thunderstorms along the monsoon 
trough, beyond 180 nm off the coasts of Nicaragua and Costa Rica.

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. Looking ahead, fresh gap 
winds are possible across the Gulf of Papagayo by Sat night.

REMAINDER OF THE AREA...

The subtropical ridge continues to dominate the waters north of 
15N. The pressure gradient between it and comparatively lower 
pressures in the tropical zone area supports a large area of 
moderate to fresh trade winds north of the ITCZ, with seas of 6 
to 7 ft. Gentle to moderate trade winds are noted elsewhere. 

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. Seas will continue to be 6 to 7 ft east
of 125W. Looking ahead, weak low pressure is expected to form 
well south of the Tehuantepec area by Fri, but not intensify as 
it tracks westward along 10N between 95W and 105W through Sun.

$$ 
Mundell