ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
Potential Tropical Cyclone Four-E Discussion Number 1
NWS National Hurricane Center Miami FL EP042025
300 PM CST Thu Jun 12 2025
Showers and thunderstorms associated with an area of low pressure
located south of Mexico, that the National Hurricane Center has been
monitoring have increased and are showing signs of organization.
While some mid-level rotation is evident in visible satellite images
near the northeast edge of ongoing convection, the low-level
circulation remains broad and elongated. However, the system is
expected to become a tropical storm tonight or tomorrow, and it is
possible that it will bring tropical storm conditions to land areas
within the next 36 to 48 hours. Therefore, the National Hurricane
Center is initiating Potential Tropical Cyclone advisories for this
disturbance.
The initial motion is more uncertain than normal since the system is
still in the formative stage, but the best estimate is
west-northwestward at about 6 kt. A northwestward to
west-northwestward motion is anticipated during the next few days as
the system moves parallel to the coast of southwestern Mexico, being
steered by a mid-level ridge. Model guidance is in fairly good
agreement with the overall track evolution, although minor track
shifts may cause greater impacts to the coast of Mexico. The NHC
forecast lies near the simple consensus aids. Since the disturbance
currently lacks a well-defined center, users are reminded that the
track forecast uncertainty is typically larger in these situations,
and future track adjustments may be required.
The models suggest a more well-defined center should develop
overnight or tomorrow. Once the system becomes better organized and
develops an inner core, the environmental conditions appear
favorable for strengthening during the next couple of days, with
warm sea surface temperatures and abundant moisture. However, the
system will be dealing with some easterly to northeasterly wind
shear. The NHC forecast shows steady strengthening over the next few
days, although there are some guidance aids such as HCCA and the
hurricane regional models that lie above the current NHC forecast.
Given some uncertainty in how quickly the system consolidates and
the limiting wind shear, the NHC forecast lies near the simple
intensity consensus aids. Beyond day 4, environmental conditions
will become hostile which should lead to weakening, and the system
should struggle to produce convection moving into cooler SSTs and a
more stable air mass. The current NHC forecast has the system
becoming a remnant low at that time, and calls for dissipation by
day 5.
Based on the NHC forecast, Tropical Storm Watches have been issued
for portions of southwestern Mexico.
KEY MESSAGES:
1. The outer bands of Potential Tropical Cyclone Four-E may bring
locally heavy rainfall to the Mexican states of Guerrero, Michoacan,
and Colima through this weekend. Isolated flooding and mudslides,
especially in areas of steep terrain, are possible.
2. The disturbance is forecast to be at tropical storm strength when
it moves near the southwestern coast of Mexico on Saturday. Tropical
storm conditions are possible over portions of that area.
FORECAST POSITIONS AND MAX WINDS
INIT 12/2100Z 11.3N 100.2W 30 KT 35 MPH...POTENTIAL TROP CYCLONE
12H 13/0600Z 12.0N 100.4W 35 KT 40 MPH...TROPICAL CYCLONE
24H 13/1800Z 13.3N 101.3W 45 KT 50 MPH
36H 14/0600Z 14.3N 102.7W 55 KT 65 MPH
48H 14/1800Z 15.5N 104.3W 60 KT 70 MPH
60H 15/0600Z 16.5N 106.2W 60 KT 70 MPH
72H 15/1800Z 17.1N 108.2W 50 KT 60 MPH
96H 16/1800Z 17.3N 112.2W 30 KT 35 MPH...POST-TROPICAL
120H 17/1800Z...DISSIPATED
$$
Forecaster Kelly
NNNN