Skip Navigation Links
NOAA NOAA United States Department of Commerce

Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 181506
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1245 UTC Tue Dec 18 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

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

The ITCZ extends from 06N94W to 07N120W to 07N132W to 06N140W. 
Scattered moderate isolated strong convection is noted from 02N 
to 07N E of 80W. Scattered moderate convection was noted from 04N
to 08N between 100W and 120W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

Gulf of Tehuantepec: Winds over the Gulf of Tehuantepec have 
diminished below gale force with seas reaching 9 ft. Winds and 
seas will diminish below advisory criteria this afternoon. The 
next gale event is expected to start by late Thu 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 before gradually diminishing.

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 Norte. The seas of 12 ft or greater will continue
to propagate SE, reaching the length of the coast of Baja 
California Sur and the Revillagigedo Islands by this afternoon. 
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 10 ft by late Wed, just 
ahead of another round of NW swell to 12 ft reaching Guadalupe 
Island and the northern coast of Baja California by late Thu. 
This swell will also decay below 12 ft rapidly, leaving 8 to 10 
ft NW swell in place for the Mexican open waters west of 105W 
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, while seas build to 5- 8 ft.

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

Fresh to strong gap winds will prevail across the Gulf of 
Papagayo and other typical gap wind zones of Central America 
today. Winds will diminish to 20 kt or less tonight.

Farther south, fresh to strong trade winds across the southwest 
Caribbean will support fresh gap winds over the Gulf of Panama 
through tonight. 

Elsewhere, gentle to moderate winds will persist, with seas 
in the 4 to 6 ft range.

REMAINDER OF THE AREA... 

High pressure of 1027 mb is centered N of the area near 32N127W.
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 10-15 ft. Seas associated to this swell have 
start to slowly subside. Another set of NW swell will move into 
the far NW waters Wed, with seas peaking near 16 ft over this
area early Wed. The NW swells will maintain seas of 8 ft or 
greater over much of the open waters W of 100W through early 
this weekend. 

$$
AL