678 
AXPZ20 KNHC 160400
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Sun Sep 16 2018

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 0000 UTC surface analysis and satellite imagery through 
0330 UTC. 

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

The monsoon trough axis extends from 1009 mb low pressure 
centered over northern Colombia near 10N75W to 14N100W to low 
pressure 1007 mb centered near 18N114W to 10N127W to beyond 
12N140W. Scattered moderate convection is from 06N to 10N E of 
87W, from 10N to 19N between 98W and 118W, and from 06N to 14N W 
of 123W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

A surface trough over the Baja Peninsula will generally maintain
light to moderate winds over the Gulf of California through Tue 
night. During the second half of the week winds are forecast to 
increase to moderate to fresh speeds over the Gulf in response to
a high pressure ridge building to the NW. This same ridge of 
high pressure will generate fresh to strong winds W of 
California, which will generate NW swell. These swell will cause 
seas to build to above 8 ft N of 27N between 121W and 131W during
the day on Thu.

Gentle to moderate NW flow will prevail across the offshore 
waters W of Baja California, with seas generally in the 5 to 7 
ft range. Expect moderate to fresh NW winds, and seas of 6 to 8 
ft N of Punta Eugenia through today as the pressure gradient 
tightens with a ridge building in from the NW. Additional pulses 
of long period S swell will continue to impact the entrance of 
the Gulf of California, and the waters W of Baja California 
through Wed.

Moderate to fresh monsoonal flow along with a 1007 mb low 
located west of the Revillagigedo Islands near 18N114W is 
supporting seas to 8 ft in the offshore waters between 102W and 
107W. This low is forecast to drift slowly west of the Baja 
California Sur offshore waters today, thus allowing for a 
decrease in the winds and seas. The low is expected to pass near 
the Revillagigedo Islands Tue and gradually develop as it tracks 
NW then N toward central Baja by Fri. This system retains a high 
chance of becoming a tropical cyclone during the next 5 days. 

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

The monsoon trough is expected to remain in the vicinity of 10N 
to 12N during the next several days. Winds will be gentle to 
moderate N of the trough and moderate to fresh S of the trough 
as a large area of disturbed weather prevails.

Cross-equatorial SW swell are decaying but will continue to 
impact the coast of Central America through Wed. Seas of 8 to 10 
ft are affecting the waters between Ecuador and the Galapagos 
Islands, and also reach to near the Azuero Peninsula. These 
marine conditions are forecast to subside today and Mon. The 
next round of SW swell is not expected until at least the end of 
next week.

REMAINDER OF THE AREA...   

A weakening surface trough constituting the remnants of Paul, 
extends from 17N133W to 25N136W. The trough will continue to 
move west and is forecast to pass 140W Sun night. High pressure 
will build north of the trough on today, which will slightly 
tighten the pressure gradient. This will result on fresh to 
strong winds from 22N to 25N between 135W and 139W with seas to 
8 ft on Sun evening. 

Otherwise, an area of fresh to strong trades will develop from 
16N to 20N between 135W and 140W Sun evening. Seas between the 
monsoon trough and this area of enhanced winds will build to 8 
ft.

$$
Ramos