000
AXPZ20 KNHC 052150
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2013 UTC Thu Jan 5 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.

...SPECIAL FEATURES...
Gulf of Tehuantepec...a gale warning has been issued for the Gulf
of Tehuantepec with the 1800 UTC forecast package. A Gulf of 
Tehuantepec gap wind event will be induced by a cold front forecast
to move across the Gulf of Mexico Friday through Saturday. Northerly
winds at 20-25 kt will begin to surge into the Tehuantepec area
early Saturday morning, then winds will quickly increase to
minimal gale force by early Saturday afternoon, with seas building
to 10 ft. Winds will further increase to 40-45 kt by Saturday
evening. Model guidance continues to indicate winds reaching storm
force (50-60 kt) by Saturday night, with seas building up to 24-25
ft. A 1036 mb high pressure center over eastern Mexico will produce
a very strong pressure gradient across the Isthmus of Tehuantepec
forcing a very strong and broad Gulf of Tehuantepec gap wind event.

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

The monsoon trough axis extends from A 1008 MB low pressure near
09N75W across the Gulf of Panama to 07N88W to 05N100W. The
intertropical convergence zone axis extends from 05N100W to
08N112W to 07N120W to 09N130W to beyond 07N140W. No significant
convection.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A weak 1020 mb high pressure persists west of the Baja California
peninsula near 25N124W, and is helping to produce 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 pressure
gradient will tighten slightly offshore of Baja California Sur
tonight into early Friday, allowing for northwest flow to increase
to moderate to fresh, then will diminish this weekend as the
gradient relaxes to the west of the peninsula.

In the Gulf of California, winds will increase to 20-25 kt early
this weekend as the pressure gradient tightens. The stronger winds
will persist through the end of the weekend, but will diminish
early next week as the gradient slackens. Seas will build to 5 to
8 ft this weekend.

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...

In the Gulf of Papagayo, winds will pulse to moderate to fresh at
night into early Saturday. Offshore flow will then increase back
to fresh to strong Saturday night, with winds approaching near
gale force by late Sunday into Monday as strong high pressure
ridges southward across interior Central America in the wake of
the Gulf of Mexico/Caribbean cold front.

In the Gulf of Panama, nocturnal northerly flow will continue to
pulse to fresh during the next few nights, increasing to fresh to
strong early next week due to the strong high pressure ridging.

These gap wind events, along with a possible storm force event in
the Gulf of Tehuantepec, will generate a very large area of high
seas that will eventually extend from Tehuantepec to Papagayo to
just northwest of the Galapagos Islands, spreading westward to
110W by early Tuesday.

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

REMAINDER OF THE AREA...

A weak cold front is over the far northwest waters and extends
from 30N135W to 26N140W followed by gentle to moderate winds and
seas up to 11 ft in NW swell. The front will stall by late
tonight, then will be reinforced and shift slightly east on Friday
before stalling again by early Saturday. Southwest winds just
ahead of the frontal boundary will increase to 20-25 kt Friday
night into Saturday with combined seas of 7 to 9 ft. The boundary
will shift eastward through the weekend, gradually weakening
through early next week.

The most recent scatterometer data shows an area of moderate to
fresh trade winds roughly from 10N-16N W of 115W due to the
pressure gradient between the aforementioned high pressure and
lower pressure in the vicinity of the ITCZ. 

$$
GR