AXPZ20 KNHC 302141
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sat Sep 30 2023
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 1800 UTC surface analysis and satellite imagery through
A tropical wave is along 100W north of 06N, moving west at 5 to
10 kt. Scattered moderate convection is noted from 06N to 16N
between 94W and 103W.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 09N84W to 11N130W. The ITCZ
extends from 11N130W to 10N140W. Scattered moderate convection
is noted from 06N to 14N and E of 116, and W of 125W.
...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Surface ridging extends across the offshore waters of Mexico with
a surface trough from SW Arizona to across the northern Gulf of
California and Baja California Norte. Fresh to strong S-SW winds
prevail in the northern Gulf of California due a tightening
pressure gradient. Fresh N winds are noted in the Gulf of
Tehuantepec. Winds are moderate or weaker elsewhere. Seas are 5-7
ft in decaying NW swell offshore Baja California, and 4-6 ft
elsewhere in the open waters. In the Gulf of California, seas are
3-6 ft in the northern Gulf, and 1-3 ft elsewhere, except 3-4 ft
near the entrance. A tropical wave is moving across portions of
southern Mexico. For details, see above.
For the forecast, the NW swell offshore Baja California will
continue to decay this evening. Otherwise, mainly moderate seas
will prevail through the middle of next week. Fresh to strong N
winds will pulse in the immediate area of the Gulf of
Tehuantepec, mainly at night, through the weekend. Fresh to
strong SW winds will pulse in the northern Gulf of California
through Sun night due to a passing pre-frontal trough and
weakening cold front. Winds will be moderate or weaker elsewhere.
Looking ahead, an area of low pressure is expected to form well
south of the coast of southwestern Mexico early next week.
Environmental conditions are expected to support gradual
development of this system, and a tropical depression is likely
to form during the middle to latter part of next week while it
moves generally northwestward. This system has a high chance for
tropical development in 7 days.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
Winds are moderate or weaker across the offshore waters. Seas
are 3-5 ft N of 10N as well as offshore Colombia to the Azuero
Peninsula, and 4-7 ft in SE-S swell elsewhere S of 10N, except
5-8 ft offshore Ecuador to the Galapagos Islands, highest S of
the Galapagos Islands.
For the forecast, winds will be moderate or weaker across the
offshore waters through the next several days. The southerly
swell will gradually decay through the weekend, then may build
back offshore Ecuador to the Galapagos Islands by the middle of
next week. Otherwise, expect moderate seas to prevail across the
remainder of the waters.
...REMAINDER OF THE AREA...
High pressure N of the monsoon trough/ITCZ is supporting moderate
to fresh winds from 10N to 26N and W of 130W. Moderate to fresh
trades prevail elsewhere from 12N to 27N and W of 130W. Winds are
moderate or weaker elsewhere as reported by latest ASCAT
scatterometer data. A shrinking area of 8-10 ft seas dominates
the waters from the Equator to 20N and W of 134W in mixed SE and
NW swell. Seas are 8-11 ft in more pure SE-S swell S of the 10N
and W of 100W. Seas are 4-7 ft across the remainder of the open
For the forecast, winds of moderate or weaker will prevail
through the next several days. The elevated seas W of 130W will
gradually decay through the weekend. A decaying cold front will
push S of 30N tonight with seas building to around 8 ft just S
of 30N Sun afternoon into early next week, with a brief
accompanying fresh northerly wind shift behind it. The southerly
swell will decay slightly by the end of the weekend, however 7-9
ft seas will linger S of the Equator through early next week.