AXPZ20 KNHC 201604
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Wed Oct 20 2021
Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 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
A tropical wave is along 94W north of 04N, moving westward at
around 10 kt. A 1010 mb low pressure is along the wave axis near
11N94W. Scattered moderate to isolated strong convection is noted
from 10N to 16N between 90W AND 100W.
A tropical wave is along 131W from 04N to 16N, moving westward
at around 10 kt. Scattered moderate to isolated strong convection
is from 08N to 11N between 123W and 131W.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from northern Costa Rica near
10N84W to 11N94W to 09N103W to 12N112W to 09N125W to 12N134W to
12N140W. Aside from the convection associated with the tropical
waves mentioned above, scattered moderate to isolated strong
convection can be found N of 06 between 78W and 84W, from 07N to
10N between 100W and 108W, from 09N to 11N between 112W and 114W,
and from 09N to 12N W of 134W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
High pressure of 1019 mb extends a ridge across the Baja California
peninsula producing gentle to moderate NW to N winds. Fresh to
strong northerly winds area noted within about 15 nm of a line
from 16N95W to 15N95.5W to 13.5N97W, including the Gulf of Tehuantepec.
Seas in this area are below 8 ft. Gentle to moderate winds prevail
in the Gulf of California.
For the forecast, a broad area of disturbed weather is producing
some disorganized showers and thunderstorms within a couple of
hundred miles of the coasts of southern Mexico, Guatemala, and El
Salvador. At 1200 UTC, a tropical wave and a low pressure of 1010
mb is analyzed in this area. Environmental conditions are expected
to be conducive for gradual development of this system during
the next few days, and a tropical depression is likely to form by
late this week or this weekend while the system moves slowly
west-northwestward to northwestward near or just offshore the
coast of southern Mexico. This system could bring an increase in
winds and seas in the Tehuantepec region toward the end of the
week. Otherwise, moderate to fresh NW-N winds are expected N of
Punta Eugenia Fri through Sun night. Seas are forecast to build
to 10 or 11 ft in NW swell. In the Gulf of California, mainly
gentle to moderate NW winds will prevail. Winds will veer to the
S and then SW in the northern part of the Gulf by Fri night as a
weakening cold front approaches from the W.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL
AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR...
As previously mentioned, a broad area of disturbed weather is
producing some disorganized showers and thunderstorms within a
couple of hundred miles of the coasts of southern Mexico,
Guatemala, and El Salvador. This system has a low chance of
tropical cyclone formation through 48 hours, and high chance
through 5 days. Please, see the latest Tropical Weather Outlook
Mainly gentle to moderate S to SW are expected across the
forecast area with seas of 3 to 5 ft in SW swell. By Sat night
into Sun, expect building seas of 6-7 ft in SW swell between
Ecuador and the Galapagos Islands.
REMAINDER OF THE AREA...
A cold front has reaches 30N140W. Seas of 8-11 ft in NW swell
follow the front forecast to dissipate by Thu. A reinforcing
cold front will move across the NW forecast waters Thu trough Fri
while gradually weakening. Seas of 12-14 ft are expected in the
wake of the front forecast to reach from 30N126W to 26N140W by
Fri evening. Seas in excess of 8 ft will dominate the waters NW
of a line from Punta Eugenia to 10N140W on Sat.