000
AXPZ20 KNHC 180206 CCA
TWDEP 

Tropical Weather Discussion...corrected
NWS National Hurricane Center Miami FL
2205 UTC Wed Aug 17 2016

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
2145 UTC.
  
...TROPICAL WAVES...

A tropical wave axis is along 89W north of 10N moving west at
15-20 kt. Associated convection is described in the section below.
Clusters of scattered moderate to isolated strong convection are
over much of the central and northern Yucatan Peninsula. Isolated
weak convection is elsewhere within 90 nm west of the wave.

The tropical wave previously along 103W has been absorbed 
into the broad circulation of another tropical wave and area of
low pressure ahead of it along 107W as described in next 
paragraph.

A tropical wave axis extends from 11N107W to 18N106W. Low
pressure of 1007 mb is along the wave near 15N107W. This 
system is moving westward around 10 kt. Latest satellite imagery 
shows scattered moderate to isolated convection from 12N to 16N
between 109W and 111W, and also within 30 nm of 15N108W. Ascat
data from overnight last night noted a swath of strong southwest
winds within 150 to 180 nm in the southeast quadrant with seas
of 8 to 10 ft. An area of 8 to 9 ft seas in southwest swell is
from 08N to 14N between 100W and 115W in southwest swell. The
associated winds and seas will persist as the low reaches to
near 18N111W by 48 hours.

A tropical wave is along 130W from 11N to 19N moving westward 
at 10-15 kt. A small and weak low is on the wave near 15N130W.
Only isolated showers and weak isolated thunderstorms are within 
60 nm of the low. A shrinking area of long period mixed swell is
producing seas to 8 ft within the points from 17N131W to 16N131W
to 17N133W to 17N131W. This area of swell is forecast to gradually
diminish in size as it migrates to the far western portion of the
area to within 60 nm of a line from 17N138W to 17N140w in 48
hours.

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

The monsoon trough axis extends from 10N84W to 13N96W. It resumes
from low pressure near 15N107W to 12N118W to low pressure near
08N125W 1010 mb. The trough axis then extends from 12N131W to 
beyond 12N140W. Scattered strong convection is south of the
axis within 60 nm of a line from 07N78W to 06N83W. Scattered
moderate to isolated strong convection is west of the axis 
from 12N to 15N between 96W and 101W. Scattered moderate
convection is within 60 nm north of the axis between 92W and 94W,
and between 117W and 119W.

...DISCUSSION... 

North of 15N east of 120W:

A weak ridge axis extends southeastward into the area from
23N120W to near the Revillagigedo Islands. A relatively weak
pressure pattern prevails across the area with surface troughing
extending from north to south along or just offshore of the Baja
California peninsula. As a result, light to moderate mainly
northwesterly flow prevails along with combined seas of 5 to 7 ft.
Low pressure currently near 15n107W will move northwest and pass
between Socorro and Clarion Islands on Friday. The low is forecast
to continue on a generally northwestward track thereafter with 
some slow development possible. Fresh to strong winds and seas of
8 to 9 ft are forecast within 180 nm in the southeast quadrant of
the low. These conditions may possibly increase by Friday pending
development of the low.

South of 15N east of 120W:

A locally tight pressure gradient prevails is within 60 nm of
the Mexican coast west of the Tehuantepec region due to the 
combination of high pressure over interior Mexico and the 1007 mb
low pressure near 15N107W described in the tropical wave section
above. The ensuing fetch is bringing seas to 8 ft in a southeast
swell there are was recently reported by ship "VRGA6" at location
15N97.5W. The persistence of this tight gradient is forecast to
lead to strong southeast winds within 60 nm of the coast of Mexico
between 103W and 105W on Thursday with seas of 8 to 9 ft. Model
guidance indicates that the gradient will weaken by Thursday as
the low pressure moves farther to the northwest.
 
Northerly winds will marginally pulse to fresh to strong in the
Gulf of Tehuantepec late tonight into early Thursday, then to
fresh levels during the overnight hours of Thursday night and
Friday night. Otherwise, mainly light to moderate winds will
prevail on either side of the monsoon trough, except pulsing to
moderate to fresh in the Gulf of Papagayo during the overnight
hours with nocturnal drainage flow. Combined seas of 4 to 7 ft
will prevail through Friday.

West of 120W:

High pressure of 1033 mb centered well north of the area near
43N140W extends a ridge southeastward through 30N134W to 23N120W.
The pressure gradient between the ridge and inverted low pressure
troughing over mainly northern California is generating gale force
northerly winds offshore of the Redwood Coast. These winds have 
ushered fresh northerly swells into the area to the north of 29N
between 126W and 134W. These conditions are forecast to diminish
on Friday as the culprit pressure gradient weakens.

$$
Aguirre