000
AXPZ20 KNHC 180950
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Fri Jan 18 2019

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.

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

A surface trough extends from 06N77W to 04N81W to 05N86W to 
05N93W. The ITCZ continues from 05N93W to 02N101W to 03N116W, 
then resumes from 05N119W to beyond 05N140W. Scattered moderate 
convection is within 30 nm N of the ITCZ between 135W and 140W.

...SPECIAL FEATURES...

Tehuantepec gale warning...Strong winds prevail over the Gulf of 
Tehuantepec, with seas in the 8 to 10 ft range. Winds will 
rapidly diminish today as the pressure gradient weakens across 
the region. The pattern will change abruptly Sat night as the 
leading edge of a strong cold front moves across the isthmus of 
Tehuantepec and into the adjacent waters of the Gulf of 
Tehuantepec. High pressure surging southward behind the front 
will intensify winds to a strong gale Sun morning, or reaching 
minimal storm force. Seas will quickly build, with wave model 
guidance suggesting values reaching near 24 ft by Sun afternoon. 
Meanwhile, a large plume of 25-35 kt winds and seas in excess of 
12 ft is expected to push far south of the Gulf of Tehuantepec 
to near 09N and between 95W and 99W by early Sun evening.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

See special features for details of a gale warning in the Gulf 
of Tehuantepec. Model guidance indicates that strong north to 
northeast gale force winds will last into early Mon, with seas 
slowly subsiding. Marine interests transiting through the Gulf 
of Tehuantepec Sun into early next week should be aware of this 
upcoming gap wind event, and take necessary action to avoid 
hazardous marine conditions over the affected waters.

Elsewhere, gentle to moderate north to northeast winds are 
indicated north of 25N, with gentle to moderate breezes 
elsewhere. A weak cold front will move into Baja California 
Norte this morning, then dissipate as it moves across Baja 
California and the Gulf of California today, accompanied by a 
new set of long-period northwest swell of 12-17 ft across the 
waters off Baja California. This swell will bring dangerous surf 
and large breaking waves across Baja California Norte today. 
High pressure building behind the front will support fresh to 
strong NW winds north of Cabo San Lucas late tonight into Sat. 

Over the Gulf of California, high pressure building over the 
Great Basin north of the area will support fresh to strong NW 
winds extending the length of the Gulf from tonight through Sat. 
The strength, fetch and duration of winds support wave heights 
to 8 ft in the southern Gulf of California by Sat night. Winds 
and seas will diminish Sun as the high weakens and shifts east.

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

The pressure gradient between high pressure northeast of the 
area and the equatorial trough will maintain strong gap winds 
across Papagayo and Panama through early Sat. Gap winds will 
continue well to the west-southwest of Papagayo, with winds 
pulsing to 30 kt early this morning. Fresh to strong northerly 
gap winds will impact the Gulf of Panama as well, extending into 
the waters south of the Azuero peninsula late tonight and early 
Sat.

Gap winds will diminish Sat and Sat night as high pressure north 
of the region shifts eastward ahead of a cold front, allowing 
the pressure gradient across the region to slacken. High 
pressure will build in the wake of the front, supporting another 
round of even stronger gap winds through the Gulfs of Papagayo 
and Panama. Winds to gale force are possible through the Gulf of 
Papagayo Mon, with seas building to 8-11 ft Sun night and Mon.

REMAINDER OF THE AREA...  

Low pressure 1011 mb centered near 05N117W is moving westward at 
10 to 15 kt. The gradient between it and high pressure over the 
northern waters is supporting fresh to strong NE winds from 13N 
to 16N between 120W and 125W along with seas of 10-11 ft. The 
low will drift westward and weaken, opening into a trough later 
today near 120W.

Large seas from 12 to 19 ft continue NW of a line from 30N116W 
to 10N137W. Seas will slowly subside as the swell sweeps SE. 
Elsewhere, seas in excess of 8 ft cover much of the forecast 
waters west of 105W.

A ridge will build across the waters north of 25N in the wake of 
the front, tightening the pressure gradient and strengthening 
winds across the subtropics. The ridge will weaken Sun, allowing 
winds and seas to decrease across the tropics. 8 to 9 ft seas 
will continue from Sun into next week south of 26N and west of 
127W in a mix of NW swell and lingering NE wind waves.

$$
Mundell