000
AXPZ20 KNHC 220907
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0907 UTC Sun Oct 22 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: High pressure building 
southward across eastern Mexico in the wake of a cold front will 
help tighten the pressure gradient over the area. In response to 
the tighter pressure gradient, fresh to strong northerly flow 
will funnel through the Chivela pass into the Gulf of 
Tehuantepec starting tonight. Winds will further increase to 
gale force by early Monday morning as the cold front moves 
through the western Gulf of Mexico. Winds may even approach 
minimal storm force by early Wednesday, with seas building to up 
to 18 ft by midweek.

...TROPICAL WAVES...

The axis of a tropical wave is near 100W N of 05N moving W at 
around 10 kt. Scattered moderate and isolated strong convection 
is noted from 08N to 10N between 97W and 99W.

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

The monsoon trough extends from 10N85W to 10N92W to 09N99W to 
10N110W to 09N120W. The ITCZ extends from 09N120W to 08.5N140W. 
Scattered moderate isolated strong convection is noted within 30
nm of the monsoon trough between 97W and 99W. Scattered moderate
convection was noted within 90 nm of the ITCZ west of 133W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the special features section above for information on
a developing gale event in the Gulf of Tehuantepec.

An overnight altimeter pass shows northerly swell is producing 
seas near 15 ft off the northernmost coast of Baja California 
Norte. The swell will propagate SE, with seas 8 ft or greater 
covering all of the offshore forecast zones W of Baja California 
through the early next week before subsiding to less than 8 ft 
by the middle of next week.

High pressure over the Great Basin region of the western United 
States has strengthened winds over the Gulf of California. Fresh
to strong winds are expected to continue through Tuesday, before
diminishing as the area of high pressure shifts eastward and the
pressure gradient weakens. Winds will be the strongest tonight 
through Monday when seas will peak around 8 ft.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
   
Gentle to moderate winds will prevail over the forecast area the
rest of the weekend, increasing to moderate to fresh S of the 
monsoon trough by Monday afternoon. NW swell originating from the
Gulf of Tehuantepec will propagate into the offshore waters of 
Guatemala and El Salvador by the middle of next week. 

REMAINDER OF THE AREA...

A set of large NW swell with seas near 15 ft will continue to 
propagate SE while gradually subsiding. Seas will subside to 
less than 12 ft this afternoon. Seas associated to this swell 
are expected to further subside, to less than 8 ft, by mid week.

$$
AL