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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 190322
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Wed Dec 19 2018

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 0000 UTC surface analysis and satellite imagery through 
0315 UTC.

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

The ITCZ extends from 06N99W to 05N116W to 04N140W. Scattered 
moderate convection is noted from 04N to 11N between 108W and 
115W, and from 10N to 19N between 115W and 130W. Isolated 
moderate convection is from 03N to 08N west of 136W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

Gulf of Tehuantepec: The next gale event is expected to start by 
Thu evening as a cold front pushes across the Gulf of Mexico 
north of the area. Strong gales with seas reaching as high as 18 
ft will persist through late Fri and early Sat. Fresh to near 
gale force winds will then prevail through the remaining weekend 
as high pressure builds along Mexico tightening the gradient in 
Tehuantepec.

Large NW swell is impacting the forecast waters, with the 
leading edge of 12 ft seas or greater noted in the waters off 
Baja California Peninsula to the Revillagigedo Islands. This 
swell will produce hazardous seas for mariners, and create large 
and powerful surf along the Pacific reefs and beaches. This high 
surf will also produce coastal flooding and beach erosion in 
many exposed locations from southern California to western 
Mexico. This swell will decay to 8 to 11 ft by Wed evening, just 
ahead of another round of NW swell to 12 ft reaching Guadalupe 
Island and the northern coast of Baja California early on Thu. 
This swell will decay below 12 ft by Thu evening, leaving 8 to 
10 ft NW swell in place for the Mexican open waters west of 110W 
through Sat.

Across the Gulf of California, strong high pressure will build 
over the Great Basin by Wed. The high will support fresh to 
strong winds across the northern and central Gulf Wed through 
Thu morning, while seas build to 5-8 ft.

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

A strong cold front will move across the SW Caribbean on Fri 
morning. Strong northerly winds behind the front will funnel 
through the Gulf of Papagayo increasing to near gale force by 
late Fri night. A strong pressure gradient between the ridge 
building behind the front and lower pressure in the SW Caribbean 
will support the continuation of the gap wind event through Sun 
night. Seas are expected to peak to 12 ft by Sat morning. Winds 
and seas will gradually diminish from Sun night to Mon night. 

Northerly fresh winds are expected in the Gulf of Panama Sat 
night through early on Mon with seas to 7 ft.

Elsewhere, gentle to moderate winds will persist, with seas 
in the 4 to 7 ft range.

REMAINDER OF THE AREA... 

High pressure of 1029 mb is centered N of the area near 31N128W.
This high will meander about this area for the next few days and
maintain a modest pressure gradient to the south and southwest, 
resulting in moderate to fresh tradewinds between 10N and 20N to 
the W of 110W. Large NW swell moving through the area is 
producing seas of 8-15 ft. Another set of NW swell will move 
into the far NW waters early on Wed, with seas peaking near 16 
ft over this area. The NW swells will maintain seas of 8 ft or 
greater over much of the open waters W of 98W through early this 
weekend. Otherwise, a surface trough will approach the western 
tropical waters on Fri night, increasing the winds to fresh to 
strong from 08N-15N west of 133W. Strong winds in this region 
are likely to increase to near gale force Sun night as the ridge 
north of the area strengthen. 

$$
NR