000
AXPZ20 KNHC 182201
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Fri Sep 18 2026

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
2145 UTC.

...SPECIAL FEATURES...

Western East Pacific: Low pressure, Invest EP98, is centered near
11N118W with a pressure of 1009 mb. This feature is part of a
rather broad area of cyclonic circulation. Satellite exhibits 
numerous moderate to isolated strong convection from 08N to 13N 
between 117W and 120W. Environmental conditions appear conducive for
development of this system, and a tropical depression is likely 
to form this weekend as it moves westward across the western 
portion of the eastern Pacific. The low has a high chance of 
tropical cyclone formation through the next 48 hours.

South of Southwestern Mexico: A tropical wave, Invest EP99, has its 
axis extending from near 16N105W to 06N106W, with low pressure of 
1010 mb, near 07N106W. This feature is part of a broad area low 
pressure that is located about 700 nautical miles south-southwest of 
the southwestern coast of Mexico. satellite imagery depicts 
disorganized scattered moderate to isolated strong convection within 
from 07N to 12N between 103W and 108W. Environmental conditions are 
conducive for development, and a tropical depression is likely to 
form late this weekend or early next week while it moves gradually 
northwestward off the coast of southwestern Mexico. This system has 
a medium chance of tropical cyclone formation through the next 48 
hours.

Please refer to the latest NHC Tropical Weather Outlook at 
website: www.hurricanes.gov for more details on these Invests.

...TROPICAL WAVES...

The southern portion of the axis of a western Caribbean Sea 
tropical is along 79W north of about 05N. It is moving westward 
near 15 kt. Numerous moderate to strong convection is within 180
nm west of the wave, and also from 03N to 05N between 79W and
81W.

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

The monsoon trough axis extends from northwest Colombia westward
to across northern Costa Rica, and southwestward to 09N86W to 
09N100W to 06N101W to 06N111W to 10N114W to low pressure, Invest 
EP98, near 11N118W and to 12N126W. It resumes at 13N138W to 
beyond 12N140W. Scattered moderate to isolated strong convection
is within 300 nm north of the trough between 93W-103W, also 
within 300 nm south of the trough between 90W-102W and 
within 120 nm south of the trough between 120W-126W.

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

The pressure gradient between a ridge over the Gulf of America 
and the eastern extension of the Pacific monsoon is supporting 
strong to near-gale force north to northeast gap winds across 
the Gulf of Tehuantepec as was evident in satellite
scatterometer from throughout the day. Seas with these winds are
6 to 8 ft. Scattered to numerous showers and thunderstorms are 
over most of the offshore waters, especially east of about 101W. 
The northern portion of tropical wave extends along 104W, 
northward to near 17N. The gradient related to high pressure west
of the Baja California offshores is supporting moderate to fresh
northwest winds N of Cabo San Lazaro. Moderate or weaker winds 
are elsewhere along with moderate seas, except for slight seas in
the Gulf of California. 

For the forecast, winds will pulse to fresh to strong speeds in 
the Gulf of Tehuantepec tonight becoming moderate north to 
northeast winds Sat afternoon. Fresh to strong northwest winds 
offshore Baja California will diminish Sat afternoon. Northwest
winds over these waters are expected to briefly reach fresh
speeds Mon night into Tue. Otherwise, the environmental 
conditions of the tropical wave that extends from 6N105W to 
06N106W, with low pressure of 1010 mb, Invest EP99, near 07N106W 
are conducive for development, and a tropical depression is 
likely to form late this weekend or early next week while it 
gradually moves north-northwestward and northward off the coast 
of southwestern Mexico. Regardless of development, this system is
forecast to bring fresh to strong winds and moderate to rough 
seas to the Michoacan and Jalisco offshores Tue night into the 
middle part of next week.

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

Fresh to strong northeast to east winds prevail across the Gulf 
of Papagayo extending downstream to near 90W. Moderate easterly 
winds from this gap event are affecting the outer offshores El 
Salvador and Guatemala. Moderate or weaker winds prevail 
elsewhere, except for moderate to fresh N winds in the Gulf of 
Panama extending to about 07N. Seas over the offshore waters 
are of moderate state due to a long-period southwest swell.

For the forecast, the pressure gradient between the ridge north 
of the area and the eastern Pacific monsoon will support pulsing 
fresh to occasionally strong easterly winds and moderate to rough
seas across the Papagayo region into early Sat, then pulsing to 
moderate to fresh speeds through early Sun. Moderate winds and 
seas will prevail elsewhere.

...REMAINDER OF THE AREA...

The remnant 1008 mb low of former Tropical Depression Fifteen-E 
is located near 17N137W. A tight gradient between the low and 
high pressure to its north is bringing fresh to strong northeast
to east winds over the waters from 19N to 27N west of 129W. Seas 
are 6 to 9 ft within this area of winds as interpreted from 
earlier satellite altimeter data passes. satellite imagery
shows numerous moderate convection within 180 nm of the low in 
the NE quadrant and 90 nm of the low in the SE quadrant. Elsewhere,
winds are moderate or weaker and seas are of moderate state,
except for rough state seas in the vicinity of Invest EP98. 

For the forecast, see the Special Features section. Otherwise, 
environmental conditions appear conducive for some development of
the remnant low of former Tropical Depression Fifteen-E as it 
moves westward to west-southwestward, and a tropical depression 
could form well to the south or southeast of the Hawaiian Islands
by the middle to latter part of next week.

$$
Aguirre