000
WTPZ42 KNHC 091440
TCDEP2
 
Tropical Depression Seventeen-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP172025
900 AM CST Thu Oct 09 2025
 
The large area of disturbed weather located near the southwestern 
coast of Mexico (Invest 90E) has continued to gain organization.  
Convective banding has become more evident in the southern and 
western part of the circulation, and the latest Dvorak estimates 
from TAFB and SAB are T2.0 and T1.5, respectively.  The convective 
pattern does suggest that the circulation might still be a bit 
elongated, but hourly observations from a cruise ship, the 
Norwegian Joy (C6CX3), helped to locate the main center of 
circulation, pressure minimum, and estimated winds.  The 
circulation and convection are now organized enough to classify the 
system as a tropical depression.

The center we're now tracking is somewhat discontinuous from a 
feature we were tracking yesterday farther to the east, and the 
initial motion is a rough estimate of west-northwestward, or 285/12 
kt.  Strong mid-level ridging over northern Mexico and the 
south-central U.S. is expected to steer the depression on a quick 
west-northwestward to northwestward track during the next 48 hours, 
with the center paralleling the southwestern coast of Mexico through 
late Friday.  The system is then likely to round the western 
periphery of the high and move toward the Baja California peninsula 
in 2-3 days.  The model guidance is in fairly good agreement for 
this first forecast, and the NHC track is close to a blend of the 
TVCE and HCCA consensus aids.

The depression is being affected by strong easterly shear which is 
likely to continue for the next 24 hours.  However, the system is 
also over very warm waters (29-30 degrees Celsius), in an 
environment of strong upper-level divergence, and moving 
quickly, which should all allow for some modest strengthening 
during that time.  The NHC forecast is near the top end of 
the guidance and close to the HCCA aid in the short term.  Although 
the shear is forecast to decrease some after 24 hours, the 
mid-level environment is expected to become drier and more stable 
while the upper-level winds become more convergent.  Those changes 
should induce weakening while the system is approaching the southern 
Baja California peninsula.  Although a remnant low point is 
provided over northwestern Mexico on day 4, it is likely that the 
system will dissipate before that time.

KEY MESSAGES:

1.  Tropical storm conditions are possible along portions of the 
coast of southwestern Mexico through late Friday.  Interests in 
southern Baja California Sur should monitor the progress of the 
system.

2.  Heavy rainfall associated with the tropical depression will 
impact coastal sections of southwestern Mexico through Saturday, 
which could result in flash flooding, particularly in areas of 
higher terrain.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/1500Z 16.2N 100.8W   30 KT  35 MPH
 12H  10/0000Z 16.8N 102.6W   40 KT  45 MPH
 24H  10/1200Z 18.1N 105.1W   45 KT  50 MPH
 36H  11/0000Z 19.8N 107.8W   40 KT  45 MPH
 48H  11/1200Z 21.4N 109.9W   35 KT  40 MPH
 60H  12/0000Z 23.3N 111.0W   30 KT  35 MPH
 72H  12/1200Z 25.5N 111.2W   30 KT  35 MPH
 96H  13/1200Z 29.2N 110.7W   15 KT  15 MPH...POST-TROP/REMNT LOW
120H  14/1200Z...DISSIPATED
 
$$
Forecaster Berg