WTPZ43 KNHC 160839
TCDEP3

Tropical Storm Mario Discussion Number  15
NWS National Hurricane Center Miami FL       EP132025
200 AM PDT Tue Sep 16 2025

After going a few hours with limited convection, Mario has had a
recent convective burst near its estimated center. Its structure
overall seems to be gradually degrading, with little in the way of
banding features, and it appears the tropical cyclone is slowly
succumbing to the increasingly negative thermodynamic conditions.
Both subjective and objective intensity estimates have been
decreasing, and the initial intensity will follow suit, lowering to
45 kt this advisory.

Without much recent microwave or scatterometer data to go on, the
estimated motion remains a somewhat uncertain 310/10 kt. Mario
should continue to move along the western periphery of a mid-level
ridge centered over northern Mexico for the next day or so, but will
slow down as it loses its vertical structure. By the end of the
forecast the shallow low-level circulation will likely drift very
slowly. The latest track forecast is slightly west of the previous
one after 24 hours, electing to remain close to a blend of the
latest HCCA and GDMI guidance aids.

Mario is now crossing the 26 degree C sea-surface temperature
isotherm and cooler waters lie ahead, in addition to a stable dry
atmosphere and increasing southwesterly shear. Thus, weakening
should continue, and Mario is likely to lose all of its organized
convection in about 24 hours as its mid-level circulation decouples
and continues propagating off to the north. The small remnant low
left behind should open up into a trough in 60-72 h. This forecast
is in good agreement with the intensity guidance aid envelope.

While Mario is forecast to dissipate as a tropical cyclone well to
the south of California, its remnant mid-level moisture will likely
spread further north, affecting portions of southern California and
Baja California later this week.


FORECAST POSITIONS AND MAX WINDS

INIT  16/0900Z 21.9N 115.7W   45 KT  50 MPH
12H  16/1800Z 23.2N 117.3W   35 KT  40 MPH
24H  17/0600Z 24.6N 118.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
36H  17/1800Z 25.6N 119.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
48H  18/0600Z 26.3N 120.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
60H  18/1800Z 26.7N 120.2W   15 KT  15 MPH...POST-TROP/REMNT LOW
72H  19/0600Z...DISSIPATED

$$