000
AXPZ20 KNHC 271535
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1535 UTC Wed Sep 27 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

The monsoon trough extends from 07N78W to 1006 mb low pressure
south of the Gulf of Tehuantepec near 15N97W to 1007 mb low
pressure centered near 13N122W to 10N140W. Scattered moderate
convection is from 04N to 07N between 77W and 84W, from 11N to
13N between 93W and 99W. Scattered moderate to isolated strong
convection is from 10N to 14N between 118W and 123W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  

1006 mb low pressure persists south of the Gulf of Tehuantepec,
supporting scattered showers and a few thunderstorms off the
Chiapas and Oaxaca coastlines. The low pressure will continue off
the coast of southern Mexico through Sunday. Fresh to strong gap
winds will develop into the Gulf of Tehuantepec by Sat night as
high pressure forms north of the area in the Gulf of Mexico. 

Farther north, the remnant low pressure of Pilar over Cabo San 
Lucas will dissipate through tonight. A weak pressure pattern 
remains in place, supporting only gentle to moderate breezes 
through Sunday north of 16N. Generally 3 to 5 ft seas will 
persist in open waters through Sat. Northerly swell will start to
propagate into the waters west of Baja California Norte Sunday 
with seas building to 5 to 7 ft. 

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

An active monsoon trough currently passes over Central America 
from Guatemala to Panama. The trough will remain close enough to 
the coast, either inland or just offshore, to produce active 
convection over the coastal waters the next few days. Moderate SW
to W winds are expected south of the trough through Sun. Lighter
trade winds are expected north of the rough axis. Long period SE
to S swell will maintain 5 to 6 ft seas west of Ecuador and 
south of the Equator during the next few days. Looking ahead, 
broad low pressure developing over Central America will cause 
monsoonal winds to surge to fresh to strong speeds west of Costa 
Rica into early next week with seas to 8 ft reaching the waters
beyond 200 nm off the coast from Nicaragua to Guatemala.

REMAINDER OF THE AREA...

Scattered showers and thunderstorms are ongoing near 1007 mb low
pressure along the monsoon trough at 13N122W. Fresh to strong SW
to W winds were noted in an earlier scatterometer pass along with
seas to 9 ft observed in an altimeter pass. The low is expected
to weaken and become more elongated along the monsoon trough
through Thu, with winds and seas gradually diminishing.
Elsewhere, weak high pressure north of the area will support
gentle to moderate trade winds across the region south of 20N.
Looking ahead, northerly swell of 8 to 9 ft will propagate into 
the waters north of 25N between 120W and 130W Sun into early 
next week.

$$
Christensen