000
AXPZ20 KNHC 092203
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2210 UTC Sun Oct 9 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
2100 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning...High pressure building
southward over eastern Mexico and the western Gulf of Mexico
will tighten the pressure gradient across the Isthmus of
Tehuantepec over the next several days. This will allow the
strong northerly gap winds currently spilling across the Gulf of
Tehuantepec to combine with nocturnal drainage effects to result
in strong winds over the next few days, reaching gale force in
the late evening and overnight hours. Gap winds may briefly
diminish to 20 to 25 kt during the afternoon hours before
surging again at night into the early morning hours. Gale force
winds are not expected after Monday night as the airmass to the
north modifies and shifts east. However, strong to near gale
force gap winds will continue to pulse into the Gulf of
Tehuantepec through the end of the week.

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

The monsoon trough extends from 09.5N74.5W to low pres near
10.5N90W to 14.5N105W to low pres near 12.5N113.5W to low pres
near 11.5N118W to low pres near 11N125W to beyond 10N140W.
Scattered moderate to strong convection is noted within 150 nm N
and 180 nm S of trough between 89W and 119W. Scattered moderate
isolated strong convection is noted within 60 nm N and 150 nm S
of trough between 126W and 140W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A weak sub-tropical ridge axis extends from northwest to
southeast across the Pacific waters to just offshore of Cabo San
Lucas on the southwestern tip of Baja California Sur. Light to
gentle northerly breezes will persist across the region north of
20N, including the Gulf of California, through the next several
days on the eastern periphery of the weak ridge. Meanwhile,
light and variable winds currently across the waters between the
Gulf of Tehuantepec and Cabo Corrientes will become northwest to
westerly and freshen through Tuesday as the ridge builds
southeastward to offshore of Manzanillo Mexico.
 

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

Moderate southwest winds persist from 05N to the monsoon trough
which is meandering north to south along roughly 10N to 11N, with
light to gentle southwest breezes farther south toward the
Galapagos Islands. Scattered showers and thunderstorms have
shifted westward away from the coast from Nicaragua to Guatemala
where light to moderate northeast winds persist. However, new
afternoon convection has begun to develop and should shift
westward through the late evening hours.  A surface low pressure
is expected to form along the monsoon trough off the coast of El
Salvador or Guatemala in the next few days. This will increase
winds especially in the waters beyond 150 nm off El Salvador and
Guatemala Monday, aided in part by a plume of strong gap winds
originating from the Gulf of Tehuantepec. The low pressure will
continue west of the area through mid week. Elsewhere combined
seas of 3 to 6 ft, primarily in long-period southwest swell, are
expected across the offshore waters later in the period from the
early to middle part of next week.

REMAINDER OF THE AREA... 

High pressure of 1018 mb centered north of the area near 38N130W
will shift southeastward through the next couple of days, ahead
of a cold front moving into the forecast area in the next 12
hours. Areas of moderate to fresh trade winds persist north of
the monsoon trough to near 20N, with seas of 5 to 7 ft. Global
models are in good agreement showing a series of broad, weak,
and transient low pressure areas forming along the monsoon
trough. Although the model depictions differ somewhat in precise
locations, there is some general agreement showing 1008 mb low
pressure currently developing near 11.5N118W will deepen over
the next couple of days and move slowly northwest, reaching near
17N125W by mid week. In addition, models are also showing the
low pressure area that will form off Central America today
gradually developing and crossing west of 120W by late
Wednesday. At a minimum, strong winds and seas of 8 to 10 ft are
likely with these two low pressure areas.
      
$$
Stripling