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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 272055
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2055 UTC Wed May 27 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 1800 UTC surface analysis and satellite imagery through
2030 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 89W north of 08N, moving 
west around 10 kt. Scattered moderate isolated strong convection
is noted within 120 nm of the wave axis south of 11N.

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

The monsoon trough extends from 06N77W to 10N90W to 1010 mb low
pressure near 12N103W to 08N137W. The ITCZ extends from 08N137W 
to beyond 08N140W. Numerous moderate isolated strong convection 
is noted N of 04N E of 87W. Scattered moderate isolated strong
convection is occurring within 120 nm of the monsoon trough
between 93W and 101W, between 104W and 109W, and between 121W and
127W.

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 this afternoon,
with light to gentle winds over much of the forecast waters. Some
locally moderate NW winds are noted in recent scatterometer data
near Los Cabos. Seas generally remain 4-6 ft offshore of Baja
California, and 5-7 ft in SW swell over the waters south of Cabo
Corrientes. 

Long-period S to SW 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 
this afternoon, with numerous showers and thunderstorms N of 04N 
noted in satellite imagery and lightning data. Moderate to fresh 
SW flow prevails south of the monsoon trough, with 4 to 7 ft seas
based on altimeter data from this morning. Note that 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 25N131W has weakened the typical
high pressure ridge over the northern waters. Moderate to fresh
winds and seas to 8 ft are likely found between this low and 
high pressure entered near 35N139W. Elsewhere, gentle to locally 
moderate winds are noted in recent scatterometer passes on 
either side of the monsoon trough/ITCZ. Weak low pressure
analyzed along the monsoon trough near 12N103W is producing
locally higher winds and seas, along with increased convection. A
recent altimeter pass in this region shows 7-9 ft seas near the
low, extending southward beyond the Equator where SW swell
lingers over the southern waters.

Low pressure near 25N131W will weaken by Fri, allowing a high
pressure ridge to build across the northern waters. Southerly
swell will decay across the far southern waters tonight, allowing
wave heights to subside below 8 ft.

$$ 
B Reinhart