AXPZ20 KNHC 122315 CCA
Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
2205 UTC Mon Nov 12 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
Based on 1800 UTC surface analysis and satellite imagery through
Gulf of Tehuantepec Storm Warning: A strong cold front will move
across the western Gulf of Mexico on Tue followed by a strong
high pressure system. Winds are forecast to first reach minimal
gale force across the Gulf of Tehuantepec by early in the
afternoon on Tue morning as strong high pressure over northeastern
Mexico surges southward along the east side of the Sierra Madre
Oriental mountains and to southeastern Mexico. The resultant
tight pressure gradient between the high pressure and the cold
front will allow for the gale force winds to quickly increase to
storm force winds of 40 to 50 kt by late Tue afternoon or early
evening. Seas downstream of the Gulf of Tehuantepec are expected
to build up to the range of 13 to 22 ft by late Tue night and
into Wed. The storm force winds are expected to continue through
late Wed night, with gale force winds likely lasting into early
Sat morning. A large swath of very high seas from this event
will propagate to the south and southwest of the Gulf of
Tehuantepec region, with the leading edge of the 8 ft seas
forecast to reach near 108W by Fri.
Gale Warning along and west of the coast of northern Baja
California: Strong high pressure building across the southwestern
United States and northern Mexico will bring strong to near gale
force northerly winds over the Gulf of California. These winds
will funnel through mountain passages across Baja California
Norte and bring minimal gale force northeast winds over regional
waters, from 28N to 30N E of 115W beginning late tonight, and
continuing through early Tue evening. Fresh to strong, to at
times strong to near gale force, northeast winds and building
seas of 8 to 10 ft are also expected across the offshore
forecast waters W of Baja California, mainly N of Cabo San
Lazaro through late Tue night.
The axis of a tropical wave extends from 07N118W to 16N117W,
moving westward at 10 to 15 kt. A 1012 mb low is just west of
the wave at 08N119W. Scattered moderate convection is within
150 nm of the low in the SE quadrant and within 120 nm of the low
in the southwest quadrant. Scattered moderate convection is
within 120 nm east of the wave from 07N to 10N.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from northern Colombia near
09N74W to Costa Rica and to 08N90W to 08N99W, where latest
scatterometer data indicates that it transitions to the ITCZ axis
to 07N100W to just east of the above described tropical wave. It
continues from just to the west of the 1012 mb low to 07N130W
and to 08N140W. Scattered moderate convection is seen within 120
nm north of the ITCZ axis between 121W and 124W and between 125W
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...Corrected
Please see the Special Features section for information on
upcoming Gulf of Tehuantepec storm event and on a gale event
off the west coast of Baja California Norte.
Gulf of California: The pressure gradient associated with strong
high pressure north of the area is bringing strong to near gale
force northwest winds over the northern and central Gulf. These
winds will spread southward across the entire length of the Gulf
of California and across the waters between Las Marias Islands
and Los Cabos by late tonight. Seas are forecast to build to 8
to 10 ft before starting to subside Tue morning as the high
pressure center north of the area moves northward and weakens.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Fresh to strong northeast winds will pulse over the Gulf of
Papagayo tonight, then diminish to fresh winds early Tue and
diminish further to moderate to fresh winds thereafter. Winds
will increase back to fresh to strong by Tue night as a tight
pressure gradient develops over northern Central America behind
a strong cold front that will move across the northwestern
Caribbean Sea. Seas are forecast to build to 9 ft by Thu
morning. This second gap wind event will last through the end of
A strong Tehunatepec gap wind event W of the area is forecast
to spread strong to near gale force winds and building seas of
12 to 18 ft into the Guatemala and El Salvador offshore waters,
mainly to the west of 92W, Tue night through Thu morning.
Otherwise, light to gentle winds are forecast north of the
monsoon trough, with gentle to moderate SW winds S of the monsoon
trough through the next several days. Cross-equatorial long
period SW swell will keep seas in the 6 to 7 ft range between
Ecuador and the Galapagos Islands, and as far north as near the
Azuero Peninsula through Wed.
REMAINDER OF THE AREA...
High pressure of 1023 centered west of California near 33N128W
extends a ridge southeastward across the northern forecast waters
to near the Revillagigedo Islands. The pressure gradient is
forecast to tighten between the high pressure and lower pressure
in the vicinity of the ITCZ from late tonight through Tue, resulting
in fresh to locally strong trades just north of the ITCZ. Seas
of 8 to 9 ft will be associated with these winds covering roughly
the waters from 10N to 16N W of 119W by Tue, with the strong
trades expected from about 10N to 15N between 122W and 126W.
These conditions are forecast to last through Thu, while they
shift westward and decrease in coverage.
A stationary front is dissipating over the far northwest section
of the area. Its remnants will lift back to the northwest and
north as a trough through Wed. Model guidance depicts that a
cold front will approach the far northwest corner of the area
on Fri. A set of northwest swell associated with the dissipating
stationary front is forecast to cross 30N140W by late Tue night
into early Wed, with seas of 8 to 10 ft covering much of the
waters north of 07N and west W of 130W by early Thu as the swell
merges with swell created by the aforementioned area of fresh
to strong trades.
Cross equatorial SW swell of 7 to 9 ft will propagate across the
waters S of 06N between 100W and 120W through early Wed.