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Eastern North Pacific Tropical Weather Discussion



807 
AXPZ20 KNHC 280918
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
813 UTC Thu May 28 2020

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 0600 UTC surface analysis and satellite imagery through
0915 UTC.

...SPECIAL FEATURES...

A Central American Gyre will develop in the eastern North Pacific
by the end of the week. The gyre will move northward toward
Central America and southern Mexico. This will advect abundant
moisture into portions of Central America by the end of the week,
through the weekend, and into next week. There is the potential
for heavy rainfall over portions of Central America, especially
from northern Costa Rica northward into southern Mexico. This
will bring the potential for life-threatening flash floods and
mudslides for the areas that receive the heaviest rainfall.
Please refer to products issued by your local weather service 
for more information.

Tropical cyclogenesis is possible in association with Central 
American Gyres. There is currently a low chance of tropical 
cyclone formation within the gyre over the next couple of days, 
and a high chance of tropical cyclone formation within the next 
five days. Please see the latest Tropical Weather Outlook for 
more information.

...TROPICAL WAVES...

The axis of a tropical wave is along 92W north of 08N, moving 
west around 10 kt. Scattered moderate convection is noted within
120 nm of the wave axis and north of 03N.

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

The monsoon trough extends from 01N71W to 11N95W to 1010 mb low 
pressure near 11N103W to a 1011 mb low near 10N114W to 1010 mb 
low near 09N124W to 1011 mb low near 10N132W. The ITCZ extends 
from 10N132W to beyond 07N140W. Scattered moderate convection
prevails from 03N-11N and east of 106W. Scattered showers are 
noted elsewhere along the boundaries.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the Special Features section for more details on the 
Central American Gyre expected to develop by the end of the week.

A weak pressure pattern prevails across the area, with a 1015 mb
high centered near 23N122W. Light to gentle winds are noted over
much of the forecast waters. Locally moderate NW winds are noted
in recent scatterometer data near Los Cabos. Seas remain 4-6 ft 
offshore of Baja California, and 5-7 ft in SW swell over the 
waters south of Cabo Corrientes.

Long-period southerly swell will continue propagating across the
southern offshore waters through the weekend. High pressure will
build over the northern waters Fri night into the weekend, 
resulting in moderate to fresh NW winds off the coast of Baja 
California. Expect increasing winds and seas over the southern 
Mexico offshore waters this weekend in association with the 
Central American Gyre and possible tropical cyclone formation.

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

Please see the Special Features section for more details on the 
Central American Gyre expected to develop by the end of the week.

The monsoon trough remains active offshore of Central America, 
with scattered showers and thunderstorms N of 03N noted in 
satellite imagery. Moderate to fresh SW flow prevails south of 
the monsoon trough, with 5 to 7 ft seas based on latest 
altimeter data. Gusty winds and locally rough seas are likely in
and near thunderstorms.

Expect increasing winds and seas over the offshore waters late 
this week and through the weekend, in association with the
Central American Gyre and possible tropical cyclone formation.

REMAINDER OF THE AREA...

Stationary low pressure near 25N130W prevails over the northern 
waters. A surface trough extends from 30N127W to the low to 
19N132W. Moderate to fresh winds and seas to 7 ft are noted 
between this low and high pressure to the north centered near 
34N142W. Elsewhere, gentle to locally moderate winds are noted 
in recent scatterometer passes on either side of the monsoon 
trough/ITCZ. Multiple low pressure centers prevail along the 
monsoon trough enhancing winds and seas, as well as convection. A
recent altimeter pass near the low centered near 11N103W shows 
7-9 ft seas near the low, extending southward beyond the Equator 
where SW swell lingers over the southern waters.

The low pressure near 25N130W will weaken by the end of the week,
allowing for high pressure ridge to build across the northern 
waters. Southerly swell will decay across the far southern waters
tonight, allowing wave heights to subside in the area.

$$
ERA