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Tropical Depression Thirteen-E Discussion Number   3
NWS National Hurricane Center Miami FL       EP132025
300 AM CST Fri Sep 12 2025
 
The depression remains poorly organized tonight, with only small 
areas of convection bursting to the west of the estimated low-level 
center. Recent scatterometer data and surface observations indicate 
the circulation remains very small. While believable scatterometer 
winds up to about 30 kt were noted offshore in the northern 
semicircle of the circulation, observations from the Acapulco 
International Airport indicated these winds did not reach the coast 
when the system made its closest approach earlier tonight. Since the 
overall satellite presentation has slightly worsened since the 
earlier scatterometer pass, the initial intensity is held at 30 kt.

The initial motion is west-northwestward (295/10 kt), and the system 
should maintain this heading during the next couple of days while 
being steered by a mid-level ridge centered over northern Mexico. 
Later this weekend through early next week, the system is forecast 
to move toward the northwest as it rounds the southwestern portion 
of the steering ridge. The NHC track forecast through 60 h has been 
nudged slightly northward this cycle, in agreement with the latest 
multi-model consensus aids.

In the near term, only modest strengthening is forecast due to the 
system's close proximity to land. Some models, including the GFS and 
ECMWF, completely lose the circulation later today. But if the 
system remains offshore and survives its close passage to the 
southwestern coast of Mexico, the environment should become somewhat 
more favorable for strengthening with weaker shear conditions over 
warm waters. Overall, the intensity guidance trended much lower this 
cycle. The updated NHC intensity forecast reflects this trend, but 
remains on the high end of the guidance envelope. Future downward 
adjustments may be necessary, and it cannot be ruled out that the 
system dissipates before the end of the 5-day forecast period.
 
 
Key Messages:
1. Heavy rainfall associated with Tropical Depression Thirteen-E
will impact southern and southwestern Mexico through Sunday, which
could result in flash flooding, particularly in areas of higher
terrain.
 
2. The depression is forecast to become a tropical storm today while 
moving parallel to the southwestern coast of Mexico. While the 
strongest winds are expected to remain offshore, gusty winds are 
possible along portions of the southwestern coast of Mexico from 
Acapulco to Manzanillo during the next day or so. Interests in these 
areas should monitor the progress of this system.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/0900Z 16.5N 100.8W   30 KT  35 MPH
 12H  12/1800Z 17.0N 102.5W   35 KT  40 MPH
 24H  13/0600Z 17.6N 104.6W   35 KT  40 MPH
 36H  13/1800Z 18.1N 106.5W   40 KT  45 MPH
 48H  14/0600Z 18.6N 108.1W   45 KT  50 MPH
 60H  14/1800Z 19.0N 109.6W   55 KT  65 MPH
 72H  15/0600Z 19.5N 110.9W   60 KT  70 MPH
 96H  16/0600Z 21.0N 113.0W   60 KT  70 MPH
120H  17/0600Z 23.0N 115.5W   45 KT  50 MPH
 
$$
Forecaster Reinhart
 
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