Skip Navigation Links
NOAA NOAA United States Department of Commerce

Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 192208
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Thu Oct 19 2017

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.

...TROPICAL WAVES...

A tropical wave is N of 04N near 89W moving slowly W around 5 
kt. Scattered moderate and isolated strong convection is noted 
from 06N to 08N between 84W and 90W. This convection is situated 
just SW of the coasts of Panama and Costa Rica.

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

The monsoon trough extends fro 09N78W to 10N121W.  The ITCZ 
continues from 10N121W to beyond 10N140W.  Scattered moderate 
convection exists within 60 nm of the trough from 95W to 110W. 
Scattered moderate and isolated strong convection is occurring 
within 60 nm of the ITCZ west of 138W.  

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High surface pressure over the Gulf of Mexico along with lower 
pressure along the Pacific monsoon trough have been forcing gap 
wind flow though the Chivela Pass in southern Mexico.  This has 
been producing a Gulf of Tehuantepec gap wind event, which 
previously was a gale.  A partial ASCAT scatterometer pass at 
1632Z over the western Gulf of Tehuantepec showed peak N to NE 
winds of 25 kt.  It's likely that near gale winds are still 
occurring of the central and eastern portion of the Gulf. No 
observations of peak wave heights have been available in the 
Gulf of Tehuantepec, though they likely are still near 10 kt.
Forcing for this gap wind event will gradually fade and drop to 
winds 20 kt or lower and seas less than 8 ft by Saturday 
afternoon.  

The next cold front pushing across the Gulf of Mexico on Sunday 
will initiate the next Tehuantepecer wind event.  This is likely 
to reach gale force on Monday through Wednesday and may approach 
storm force on Wednesday.

A cold front is currently northwest of our region.  As the front 
approaches the Baja California peninsula on Friday, winds along 
the northwest coast will reach strong breeze out of the 
northwest Friday morning and continue only through Saturday 
afternoon.  While winds associated with the cold front will 
quickly diminish, large 12 to 16 ft NW swell will be reaching 
the zones along the northwest coast of the Baja California 
peninsula starting Friday night.  These swell are the result of 
a large and powerful low pressure system along the Alaska 
coastline.  This large 15-20 second period swell will reach the 
zones near the southwestern coast of the Baja California 
peninsula on Saturday and then drop below 12 ft late Sunday.  8 
to 12 ft NW swell will reach the zones near southwestern Mexico 
by early Sunday and fade by late Monday.  

As high pressure builds in over the U.S. Great Basin, N to NW 
winds will set up over the Gulf of California from Sunday 
through Tuesday.  Currently, these are forecast to reach strong 
breeze conditions, though near gale are certainly possible. 
Accordingly, wind waves from the long fetch of N to NW winds 
blowing lengthwise through the Gulf of California are 
anticipated to reach up to 8 ft.  

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

No winds of strong breeze or greater are expected in the area 
for the next several days.  Tonight, seas of 8 ft will be 
reaching the southernmost zones from a combined SE and S swell. 
This will diminish by early Saturday.  

REMAINDER OF THE AREA...

A cold front is currently northwest of our region.  As the front 
approaches the Baja California peninsula on Friday, winds along 
the northwest coast will reach strong breeze out of the 
northwest Friday morning and continue only through Saturday 
afternoon.  Elsewhere winds associated with the front will 
remain at 20 kt or less.  Rapidly building seas associated with 
long-period 15-20 second swell will reach the northwestern 
corner of our region tonight.  These will reach 12 to 16 ft and 
are the result of a large and powerful low pressure system along 
the Alaska coastline. The swell will push southeastward across 
most of the region, while gradually diminishing over the next 
few days.  Peaks seas will drop below 12 ft Sunday afternoon and 
the 8 ft swell will finally diminish by Wednesday.  

The tradewinds are fresh breeze and weaker across the remainder 
of the areas.  These should remain weak for the next several 
days.

No tropical cyclone formation is anticipated over the next 
several days.

$$ 
Forecaster Landsea