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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 180934

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Mon Dec 18 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 
0800 UTC.


The ITCZ extends from 05.5N93W TO 11N116W to beyond 10N140W. 
Scattered moderate was noted from 06.5N to 10.5N between 121W 
and 139W. 



Gulf of California: A cold front extends from low pres near 
30.5N112.5W across Sonora, Mexico to near 27.5N110W then SW 
across the Gulf of California and Baja California Sur to Cabo 
San Lazaro near 25N112W to near 24N118W. The low pressure will 
shift NE of the area today and drag the weakening front SE 
across south portions of the gulf before dissipating. Recent 
scatterometer data showed strong NWly winds N of 29.50N and W of 
113.5W in the far N gulf. These winds will diminish to 20 kt or 
less this afternoon. Elsewhere N of the front, winds are 
generally NW to N at 10-18 kt, and seas 2 to 5 ft. Moderate 
northerly winds are expected across much of the gulf through 
late Wednesday before the next front sweeps SSE into the area. 
This will bring about strengthening Nly winds once again over 
the northern gulf Thursday.

Slowly subsiding NW swell prevails off the coast of Baja 
California, with seas still 8 to 12 ft. Seas will continue to 
subside, and fall below 8 ft by Tuesday. A fresh pulse of NW 
swell will propagate into the waters off the coast of Baja 
California Norte Thursday behind the next front, with seas 
building to near 9 ft. Elsewhere, gentle to moderate winds and 4 
to 6 ft seas will persist along the coast of Mexico outside of 
the Gulf of Tehuantepec through mid week.

Active convection continues in a broad zone across the offshore 
waters of SW Mexico from the Manzanillo to Cabo Corrientes areas 
SW to near 16N110W. An upper level trough that supported the 
front that has moved through the Gulf of California lingers 
across the region, with upper level jet energy enhancing this 
convection. Active weather will continue across this region 
through Tue before shifting SW and well offshore.

Gulf of Tehuantepec: Winds will pulse to fresh to strong each 
night over the Gulf of Tehuantepec through Thu morning.


Fresh to strong NE winds will prevail across the Gulf of 
Papagayo through Fri, pulsing to around 25 kt late each night, 
where seas will build 7-8 ft. Fresh Nly winds over the Gulf of 
Panama tonight will diminish to 10-15 kt by this afternoon 
and then become strong again Mon night.

REMAINDER OF THE AREA... Northerly swell continues to slowly 
subside over the area. Seas remain 12-13 ft over the northern 
waters. Moderate to fresh winds prevail elsewhere over the 
forecast waters north of the ITCZ to 20N and west of 125W. High 
pressure across the NE Pacific will dominate the regional waters 
for the next few days with little change wind speeds. Seas 
across much of the region west of 110W will subside below 8 ft 
during the next couple of days as long period NW swell continue 
to decay.