087 
AXPZ20 KNHC 151538
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1457 UTC Sat Sep 15 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 1200 UTC surface analysis and satellite imagery through
1415 UTC. 

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

The monsoon trough axis extends from 1009 mb low pressure 
centered over northern Colombia near 09N74W to low pressure 1009 
mb centered near 16N109W to 10N119W to 14N131W to beyond 14N140W.
A broad area of scattered moderate isolated strong convection 
associated with these features is present within an area bounded 
by 04N78W to 08N99W to 08N112W to 19N115W to 24N112W to 22N106W 
to 18N103W to 13N88W to 07N78W to 04N78W. A smaller area of 
convection associated with the western portion of the trough is 
found within an area bounded by 07N120W to 08N130W to 12N127W to 
07N120W.

...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.

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 Sun as the pressure gradient 
tightens with a ridge building in from the NW. Additional pulses 
of long period southerly swell will continue to impact the 
entrance of the Gulf of California, and the waters W of Baja 
California through Wed.

A 1009 mb low pressure centered SW of the Jalisco offshore 
waters near 16N109W supporting seas to 8 ft in the Guerrero 
offshore waters. This low is forecast to drift slowly west of the
Baja California Sur offshore waters Sun, 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 through 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 will wander in the vicinity of 10N 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 to the W helps maintain monsoonal flow during 
the next few days.

Cross-equatorial SW swell are decaying but will 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 will persist today, but subside Sun 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 17N132W to 26N135W. The trough will continue to 
weaken and move westward and is forecast to pass to the west of 
the area Mon. High pressure will build north of the trough on 
Sun, which will slightly tighten the pressure gradient. This will
result on fresh to strong winds from 22N to 24N between 135W and
139W with seas to 8 ft on Sun evening. 

Otherwise, an area of moderate to fresh trades will develop N of
the monsoon trough and W of 125W during the second half of the
week as high pressure to the N builds. Seas between the monsoon
trough and 20N to the W of 130W could build to between 8 and 9 ft
during this time frame.

$$
CAM