Tropical Depression Ten-E Forecast Discussion

686 
WTPZ45 KNHC 230233
TCDEP5

Tropical Depression Ten-E Discussion Number   2
NWS National Hurricane Center Miami FL       EP102024
900 PM CST Sun Sep 22 2024

Satellite images show that the depression is gradually becoming 
better organized, with some convective banding features developing 
around the circulation and a small area of very cold cloud tops 
over the estimated center.  Upper-level outflow is fairly well 
defined over the southern semicircle of the system.  Subjective 
Dvorak classifications from both TAFB and SAB indicate a T-number of 
2.0, so the advisory intensity is held at 30 kt for now.

Center fixes indicate little movement since earlier today, so the 
initial motion estimate is nearly stationary.  As noted earlier, 
the track forecast for this tropical cyclone is quite problematic, 
with a large spread in the guidance models.  The regional hurricane 
models are generally east of the global guidance, with the ECMWF on 
the western side of the model tracks.  The most recent run of the 
GFS takes the cyclone inland in a couple of days but later 
develops one or two new centers offshore.   Since the dominant 
steering mechanism seems to be the Central American Gyre, the 
official track forecast shows a mainly east-northeastward motion 
during the forecast period, along the southern periphery of the 
Gyre.  This track moves the center close to the southern coast of 
Mexico for several days before making landfall, and lies between 
the simple and corrected dynamical model consensus predictions.  

During most of the forecast period, the system should remain over 
very warm waters with low vertical wind shear and in a moist low- 
to mid-level air mass.  Therefore strengthening is likely, and the 
official intensity forecast is similar to the statistical-dynamical 
LGEM guidance.  One major source of uncertainty in the forecast is 
how much the system interacts with land during the next few days.  
Given the favorable environment, it is possible that the system 
could become a hurricane before landfall.  Interests along the coast 
of southern Mexico should closely monitor the latest forecast 
updates for this system.  A Hurricane Watch could be required for a 
portion of the coast now covered by a Tropical Storm Watch. 


KEY MESSAGES:

1. Slow-moving Tropical Depression Ten-E will bring very heavy 
rainfall to coastal portions of southwest Mexico through the 
upcoming week.  This heavy rainfall will likely cause significant 
and possibly catastrophic, life-threatening flash flooding and 
mudslides to the Mexican States of Chiapas, Oaxaca, and southeast 
Guerrero, particularly in areas near the coast.  

2. The depression is forecast to become a tropical storm later 
tonight or on Monday.   A Tropical Storm Watch is in effect for a 
portion of the coastline of southern Mexico, where tropical storm 
conditions could begin on Tuesday.

3. The system could strengthen more than forecast depending on how 
long it remains over water. Interests along the coast of southern 
Mexico should monitor the latest forecast updates, as a Hurricane 
Watch could be required for a portion of the coastline later tonight 
or on Monday.


FORECAST POSITIONS AND MAX WINDS

INIT  23/0300Z 13.9N  98.6W   30 KT  35 MPH
 12H  23/1200Z 14.3N  98.3W   35 KT  40 MPH
 24H  24/0000Z 14.6N  97.9W   45 KT  50 MPH
 36H  24/1200Z 15.0N  97.1W   50 KT  60 MPH
 48H  25/0000Z 15.2N  96.3W   55 KT  65 MPH
 60H  25/1200Z 15.6N  95.2W   55 KT  65 MPH
 72H  26/0000Z 16.3N  94.1W   45 KT  50 MPH...INLAND
 96H  27/0000Z...DISSIPATED

$$
Forecaster Pasch