000
AXPZ20 KNHC 202138
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1928 UTC Tue Jun 20 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
2100 UTC.

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

The monsoon trough axis extends from 09N84W to 09N100W to 
10N110W to 09N130W. The ITCZ continues from 09N130W to beyond 
08N140W. Scattered moderate to isolated strong convection can be
found within 120 nm south of the Monsoon Trough between 84W and
90W, within 90 nm north of the Monsoon Trough between 92W and 
97W, and from 09N to 12N between 105W and 117W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High pressure of 1031 mb, located well north of the area near
40N138W, extends a ridge SE to near the Revillagigedo Islands. 
The ridge will shift westward through late Wednesday as a 
surface trough develops near the Baja California Peninsula. The 
trough will also drift westward. A broad and weak low pressure is
forecast to develop along the trough axis near 18N118W by 
Wednesday night. Moderate northwest winds will persist off the 
coast of Baja California norte, shifting to the southwest off 
Baja California Sur starting Wednesday as the above mentioned 
trough develops and shifts westward. Moderate to locally fresh 
southerly winds are noted per scatterometer data across the Gulf 
of California south of 27N. Winds are forecast to increase to 20
kt across the northern part of the Gulf Wednesday night into 
Thursday.

Long period northwest swell will propagate into the waters off
Baja California Norte beyond 150 nm tonight through Friday. 

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

Gentle to moderate SW to W winds are expected across the entire 
forecast area through Wed, then the pressure gradient will 
gradually relax with a gentle SW breeze continuing through Sat 
night. Long period SW swell will continue to reach the area, but
seas are expected to subside to 6-7 ft by tonight. 

REMAINDER OF THE AREA...
 
A ridge dominates most of the north waters. Scatterometer and 
altimeter passes from the past several hours indicated an area 
of moderate to fresh winds and seas of 8 to 10 ft roughly north 
of 23N west of 125W. The ridge will continue to dominate the
waters north of 15N and west of 120W on Wednesday. Northerly
swell will continue to propagate across the north waters, with
seas of 8 to 10 ft affecting mainly the waters north of 23N west
of 120W through Thursday. 

A surface trough extending south, from currently tropical storm 
Cindy located over the Gulf of Mexico, across the Yucatan 
Peninsula and SE Mexico is acting as the focus for locally heavy 
rains.

$$
GR