000
AXPZ20 KNHC 161531
TWDEP
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Tue Sep 16 2025
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
1500 UTC.
...SPECIAL FEATURES...
Tropical Storm Mario is centered near 22.7N 117.2W at 16/1500
UTC, moving northwest at 11 kt. Estimated minimum central
pressure is 1004 mb. Maximum sustained wind speed is 40 kt with
gusts to 50 kt. Peak seas are currently around 5.0 m or 15 ft.
Nearby convection is diminishing with only isolated moderate now
present. Mario is moving toward the northwest and this general
motion is expected to continue with a decrease in forward speed
over the next couple of days. Mario will continue to weaken and
is expected to become a post-tropical remnant low within the next
day. While Mario is forecast to dissipate as a tropical cyclone
well to the south of California, its remnant moisture will
spread farther north, affecting portions of the southwestern
United States by mid to late week. Locally heavy rainfall and
some instances of flash flooding will be possible by Thursday.
Please refer to your local National Weather Service office for
more details. Please read the latest HIGH SEAS FORECAST issued
by the National Hurricane Center at website
- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest
Mario NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.
Off the Coast of Southwestern Mexico (Invest EP96):
An area of 1008 mb low pressure located several hundred nautical
miles off the coast of southern Mexico near 11.5N103W continues
to produce a broad area of disorganized showers and thunderstorms
as is described in the ITCZ/monsoon trough section below.
Associated winds are currently 20-25 kt with a large area of
surrounding seas of 8-11 ft in S to SW swell. Environmental
conditions appear conducive for additional development of this
system, and a tropical depression is likely to form during the
middle to latter part of this week as it moves west-northwestward
at 10 to 15 kt over the central east Pacific. There is a medium
chance for tropical development in the next 48 hours and a high
chance for development in the next 7 days. Please read the latest
NHC Tropical Weather Outlook at website -
https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details.
...TROPICAL WAVES...
A tropical wave is moving into the western Caribbean Sea
extending southward along the Pacific coast of Colombia with
axis near 77W, moving west at 15-20 kt. Nearby convection is
described below.
A tropical wave is near 103W, from 01N to 17N near the SW coast
of Mexico, moving slowly west around 5 kt. Nearby convection is
discussed in the ITCZ/monsoon trough section below. Please see
the Special Features section above for more on the possibility
of tropical development with this tropical wave and associated
low pressure along it.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 1010 mb low pressure over
northern Colombia near 10.5N74.5W to near the Gulf of Panama and
Azuero Peninsula to 1008 mb low pressure, Invest EP96, near
11.5N103W to 1011 mb low pressure near 10N135.5W to beyond
10N140W. Numerous moderate isolated strong convection is noted
from 02N to 10N between 77W and 90W, from 12N to 19N between 92W
and 113W, and from 05N to 12N between 95W and 122W. Scattered
moderate convection is noted within 90 nm either side of the
monsoon trough between 130W and 140W.
...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Please refer to the SPECIAL FEATURES section for information
regarding Tropical Storm Mario, and for another area being
monitored for tropical development, Invest EP96.
A plume of fresh to strong NE to E winds extends from the Gulf of
Tehuantepec southwestward with seas to around 8 ft. Otherwise,
outside of the conditions associated with Tropical Storm Mario,
gentle to moderate winds dominate the open waters off Mexico as
well as over the Gulf of California. Seas are in the 5-7 ft
range off the Baja California peninsula, and 6-8 ft over the
remainder of open waters off Mexico. Seas are in the 1-3 ft range
over the Gulf of California, reaching 5 ft at the entrance of
the Gulf.
For the forecast, Mario will weaken to a tropical depression
near 23.7N 118.2W this evening, become a remnant low and move to
24.9N 119.4W Wed morning, 25.8N 120.1W Wed evening, 26.0N 120.5W
Thu morning, and dissipate Thu evening. Fresh to locally strong
winds will pulse in the Gulf of Tehuantepec through midweek, with
moderate to fresh winds pulsing afterwards. Increasing winds and
seas are possible with the area of low pressure, EP96, being
monitored for tropical cyclone development as discussed in the
Special Features section. Winds will be moderate or weaker
elsewhere with moderate to locally rough seas, except slight in
the Gulf of California.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
Moderate to fresh gap winds prevail over the Gulf of Papagayo,
with light to gentle winds elsewhere N of the monsoon trough.
Gentle to moderate winds are south of the monsoon trough, except
locally fresh from the Equator to 05N. Seas are in the 6-9 ft
range in S to SW swell across the discussion waters.
For the forecast, rough seas over the regional waters will
subside through Wed. Locally rough seas may persist offshore
offshore of Colombia through Costa Rica into early Thu. Moderate
to fresh NE gap winds will pulse in the Gulf of Papagayo through
midweek. Moderate to locally fresh S to SW winds are expected
south of the monsoon trough the week.
...REMAINDER OF THE AREA...
Please refer to the SPECIAL FEATURES section for information
regarding Tropical Storm Mario, and for another area being
monitored for tropical development, Invest EP96.
Outside of conditions associated with Mario and EP96, several
small areas of low pressure are embedded along the monsoon trough
west of 110W with locally fresh to strong winds and seas to 8 ft.
Elsewhere N of the monsoon trough, gentle to moderate winds, and
seas of 4-7 ft. Moderate to fresh winds prevail S of the monsoon
trough. Seas S of the monsoon trough are in the 5-7 ft range W
of 120W, and 6-11 ft E of 120W in S to SW swell.
For the forecast, Mario will weaken to a tropical depression
near 23.7N 118.2W this evening, become a remnant low and move to
24.9N 119.4W Wed morning, 25.8N 120.1W Wed evening, 26.0N 120.5W
Thu morning, and dissipate Thu evening. Fresh to strong SW to W
winds and rough seas will persist near the monsoon trough through
at least midweek, mainly between 105W and 130W. Rough seas south
of 05N will slowly subside on Tue, while rough seas from 05N to
15N will prevail through midweek as a potential tropical cyclone
develops, EP96. A cold front may move through the northern
waters late this week, leading to increasing NE winds and
building seas north of 25N and west of 120W into the upcoming
weekend.
$$
Lewitsky
AXPZ20 KNHC 161531
TWDEP
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Tue Sep 16 2025
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
1500 UTC.
...SPECIAL FEATURES...
Tropical Storm Mario is centered near 22.7N 117.2W at 16/1500
UTC, moving northwest at 11 kt. Estimated minimum central
pressure is 1004 mb. Maximum sustained wind speed is 40 kt with
gusts to 50 kt. Peak seas are currently around 5.0 m or 15 ft.
Nearby convection is diminishing with only isolated moderate now
present. Mario is moving toward the northwest and this general
motion is expected to continue with a decrease in forward speed
over the next couple of days. Mario will continue to weaken and
is expected to become a post-tropical remnant low within the next
day. While Mario is forecast to dissipate as a tropical cyclone
well to the south of California, its remnant moisture will
spread farther north, affecting portions of the southwestern
United States by mid to late week. Locally heavy rainfall and
some instances of flash flooding will be possible by Thursday.
Please refer to your local National Weather Service office for
more details. Please read the latest HIGH SEAS FORECAST issued
by the National Hurricane Center at website
- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest
Mario NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.
Off the Coast of Southwestern Mexico (Invest EP96):
An area of 1008 mb low pressure located several hundred nautical
miles off the coast of southern Mexico near 11.5N103W continues
to produce a broad area of disorganized showers and thunderstorms
as is described in the ITCZ/monsoon trough section below.
Associated winds are currently 20-25 kt with a large area of
surrounding seas of 8-11 ft in S to SW swell. Environmental
conditions appear conducive for additional development of this
system, and a tropical depression is likely to form during the
middle to latter part of this week as it moves west-northwestward
at 10 to 15 kt over the central east Pacific. There is a medium
chance for tropical development in the next 48 hours and a high
chance for development in the next 7 days. Please read the latest
NHC Tropical Weather Outlook at website -
https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details.
...TROPICAL WAVES...
A tropical wave is moving into the western Caribbean Sea
extending southward along the Pacific coast of Colombia with
axis near 77W, moving west at 15-20 kt. Nearby convection is
described below.
A tropical wave is near 103W, from 01N to 17N near the SW coast
of Mexico, moving slowly west around 5 kt. Nearby convection is
discussed in the ITCZ/monsoon trough section below. Please see
the Special Features section above for more on the possibility
of tropical development with this tropical wave and associated
low pressure along it.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 1010 mb low pressure over
northern Colombia near 10.5N74.5W to near the Gulf of Panama and
Azuero Peninsula to 1008 mb low pressure, Invest EP96, near
11.5N103W to 1011 mb low pressure near 10N135.5W to beyond
10N140W. Numerous moderate isolated strong convection is noted
from 02N to 10N between 77W and 90W, from 12N to 19N between 92W
and 113W, and from 05N to 12N between 95W and 122W. Scattered
moderate convection is noted within 90 nm either side of the
monsoon trough between 130W and 140W.
...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Please refer to the SPECIAL FEATURES section for information
regarding Tropical Storm Mario, and for another area being
monitored for tropical development, Invest EP96.
A plume of fresh to strong NE to E winds extends from the Gulf of
Tehuantepec southwestward with seas to around 8 ft. Otherwise,
outside of the conditions associated with Tropical Storm Mario,
gentle to moderate winds dominate the open waters off Mexico as
well as over the Gulf of California. Seas are in the 5-7 ft
range off the Baja California peninsula, and 6-8 ft over the
remainder of open waters off Mexico. Seas are in the 1-3 ft range
over the Gulf of California, reaching 5 ft at the entrance of
the Gulf.
For the forecast, Mario will weaken to a tropical depression
near 23.7N 118.2W this evening, become a remnant low and move to
24.9N 119.4W Wed morning, 25.8N 120.1W Wed evening, 26.0N 120.5W
Thu morning, and dissipate Thu evening. Fresh to locally strong
winds will pulse in the Gulf of Tehuantepec through midweek, with
moderate to fresh winds pulsing afterwards. Increasing winds and
seas are possible with the area of low pressure, EP96, being
monitored for tropical cyclone development as discussed in the
Special Features section. Winds will be moderate or weaker
elsewhere with moderate to locally rough seas, except slight in
the Gulf of California.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
Moderate to fresh gap winds prevail over the Gulf of Papagayo,
with light to gentle winds elsewhere N of the monsoon trough.
Gentle to moderate winds are south of the monsoon trough, except
locally fresh from the Equator to 05N. Seas are in the 6-9 ft
range in S to SW swell across the discussion waters.
For the forecast, rough seas over the regional waters will
subside through Wed. Locally rough seas may persist offshore
offshore of Colombia through Costa Rica into early Thu. Moderate
to fresh NE gap winds will pulse in the Gulf of Papagayo through
midweek. Moderate to locally fresh S to SW winds are expected
south of the monsoon trough the week.
...REMAINDER OF THE AREA...
Please refer to the SPECIAL FEATURES section for information
regarding Tropical Storm Mario, and for another area being
monitored for tropical development, Invest EP96.
Outside of conditions associated with Mario and EP96, several
small areas of low pressure are embedded along the monsoon trough
west of 110W with locally fresh to strong winds and seas to 8 ft.
Elsewhere N of the monsoon trough, gentle to moderate winds, and
seas of 4-7 ft. Moderate to fresh winds prevail S of the monsoon
trough. Seas S of the monsoon trough are in the 5-7 ft range W
of 120W, and 6-11 ft E of 120W in S to SW swell.
For the forecast, Mario will weaken to a tropical depression
near 23.7N 118.2W this evening, become a remnant low and move to
24.9N 119.4W Wed morning, 25.8N 120.1W Wed evening, 26.0N 120.5W
Thu morning, and dissipate Thu evening. Fresh to strong SW to W
winds and rough seas will persist near the monsoon trough through
at least midweek, mainly between 105W and 130W. Rough seas south
of 05N will slowly subside on Tue, while rough seas from 05N to
15N will prevail through midweek as a potential tropical cyclone
develops, EP96. A cold front may move through the northern
waters late this week, leading to increasing NE winds and
building seas north of 25N and west of 120W into the upcoming
weekend.
$$
Lewitsky