000
AXPZ20 KNHC 210233
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
028 UTC Wed Jun 21 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 0000 UTC surface analysis and satellite imagery through
0215 UTC.

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

The monsoon trough axis extends from 10N86W to 09N95W to 11N105W
to 11N120W to 09N130W. The ITCZ continues from 09N130W to beyond
08N140W. A cluster of moderate to isolated strong convection is
from 09N to 11N between 115W and 118W. Similar convection is
within 75 nm south of trough between 110W and 113W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High pressure of 1032 mb, located well north of the area near 
42N138W, extends a ridge SE to near the Clarion Island. The 
ridge will shift westward through late Wednesday as a surface 
trough develops near the Baja California Peninsula, where 
pressures are falling. 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. Latest scatterometer pass provided observations of 
moderate to locally fresh southerly winds across the Gulf of 
California south of 27N. Winds are forecast to increase to 20 kt 
across the northern part of this Gulf Wednesday night into 
Thursday.

Long period northwest swell will reach parts of forecast zone 
PMZ011 building seas to 8 ft 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, and to 5-6 ft
on Thursday.

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 130W. 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 11 ft affecting mainly the forecast area north of 
24N west of 120W through friday. 

A surface trough, associated with the circulation of tropical 
storm Cindy located over the Gulf of Mexico, extends across the 
Yucatan Peninsula and SE Mexico. This feature is acting as the 
focus for locally heavy rains. The mexican states of Yucatan,
Quintana Roo, Chiapas and Oaxaca reported rainfall amounts 
between 3 and 4 inches during the last 24 hours ending this
morning at 8 am.

$$
GR