000
AXPZ20 KNHC 060906
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
533 UTC Fri Jan 6 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...
A storm warning is in effect for the Gulf of Tehuantepec, the
strongest Gulf of Tehuantepec event of the season thus far. A
strong cold front is forecast to move across the Gulf of Mexico
Friday through Saturday with strong high pressure, reaching as
high as 1043 mb, building over Texas. There will be a very tight
pressure gradient between this area of high pressure and lower
pressure in the vicinity of the monsoon trough/ITCZ. Northerly
winds of 20-30 kt will rapidly surge into the Tehuantepec area
early Saturday morning. Winds will quickly increase to gale force
by early Saturday afternoon, with seas building to 10-11 ft. Winds
will continue to increase to storm force near 60 kt Saturday night
with seas building to near 22 ft. Gale force winds are expected to
expand well downstream from the Isthmus of Tehuantepec by early
Sunday. Winds are forecast to diminish below storm force Sunday
night, but gale force winds are expected to persist across the
Tehuantepec region through late Tuesday.

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

The monsoon trough extends from 08N83W to 1010 MB low pressure
near 05N89W to a 1010 mb low pressure near 06N108W to a third
1010 mb low pressure near 07N118W to 06N121W. The ITCZ continues
from 06N121W to 07N130W to 07N140W. There is no significant
convection.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see above for more details on the Gulf of Tehuantepec storm
force gap wind event.

Outside of the Gulf of Tehuantepec region, 1018 mb high pressure
centered west of the forecast waters near 24N126W extends a ridge
se to near 14N106W. The pressure gradient between this area of
high pressure and surface troughing over Mexico is producing gentle
to moderate northwest winds across the Pacific waters off the
coast of Baja California, with seas in the 3 to 5 ft range. The
area of high pressure will shift northeastward over the next 24
hours. This will increase surface pressures slightly over the
waters off the western coast of the Baja California peninsula
while a surface trough prevails over the Gulf of California. This
will strengthen winds over the central and southern portion of the
Gulf of California tonight through Saturday night. The ridge will
weaken by Sunday which will diminish winds below advisory criteria
over this area.

Elsewhere between Cabo Corrientes and the Tehuantepec region,
light to gentle breezes and seas in the 3 to 5 ft range, primarily
in northwest swell, will prevail over the next several days.
  
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

The high pressure building behind the cold front responsible for
the Gulf of Tehuantepec storm event will help for gap winds to
increase to near gale force over the gulfs of Papagayo and
Fonseca late Saturday night into Sunday morning. These winds
map reach near gale force by late Sunday into Monday.

In the Gulf of Panama, fresh nocturnal northerly flow is expected
through Sunday night. Winds will further increase to 20-25 kt on
Monday as strong winds funnel from the SW Caribbean into the Gulf
of Panama as high pressure behind the cold front over the
Caribbean waters helps tighten the pressure gradient. 

These gap wind events, along with a possible storm force wind
event in the Gulf of Tehuantepec, will generate a large area of 8
ft seas or greater that will eventually extend from Tehuantepec
and Papagayo regions southward to near 4N-5N and westward to near
110W by early Monday.

Elsewhere, light to moderate south to southwest winds will
prevail south of the monsoon trough region, with seas 5 ft or
less through the upcoming weekend.

REMAINDER OF THE AREA...

A weak cold front is over the far northwest waters. Northwest
swell associated to the front is covering the waters west of a
line from 30N131W to 14N140W. A stronger cold front will reach
the northwest waters by Saturday evening. Fresh to strong winds
will accompany the front. 

A weak pressure gradient prevails over the forecast waters north
of the ITCZ to near 20N with gentle to moderate winds prevailing.
The pressure gradient will remain weak over this area through the
forecast period with winds and seas expected to remain below
advisory criteria through at least Monday. 

$$
AL