Tropical Depression Eleven-E Forecast Discussion

000
WTPZ41 KNHC 012055
TCDEP1

Tropical Depression Eleven-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP112024
300 PM CST Tue Oct 01 2024

The small area of low pressure we have been monitoring for the past 
couple of days has become well-defined on satellite imagery this 
afternoon and was confirmed with recent scatterometer data.  There 
has been enough organized deep convection today to consider this a 
tropical depression, as suggested by the Data-T estimate from 
TAFB, and the initial wind speed is set to 30 kt in accordance with 
the max believable scatterometer values.

The initial motion is an uncertain 360/4 kt.  The depression has 
been moving northward on the eastern end of the monsoon trough, and 
this general track is anticipated through landfall with little 
change seen in the steering flow for the next day or two.  However, 
the model guidance is all over the place, owing to differences in 
the initial depth of the tropical depression and strength of the 
circulation associated with the monsoon trough and Invest 97E.  The 
ECMWF model seems to have the best representation of the initial 
vortex, and the track forecast heavily leans on that model 
solution, especially given its recent successes with cyclones in 
that area.  However, there is considerable spread in the guidance, 
and the tropical storm warning is larger than typical based on that 
uncertainty.

Northeasterly shear is expected to continue to affect the 
depression through landfall, though very warm SSTs and a moist 
mid-level environment should promote some strengthening.  These 
conditions would seem to favor intensification through landfall, 
and the first forecast shows a mid-range tropical storm, above most 
of the model guidance.  At this point, extreme rainfall and flash 
flooding seem to be the biggest threats from this system.


KEY MESSAGES:

1. The depression is forecast to become a tropical storm later 
tonight or on Wednesday.   A Tropical Storm Warning is in effect 
for a portion of the coastline of southern Mexico, where tropical 
storm conditions are expected to begin on Wednesday.

2. Tropical Depression Eleven-E will likely bring heavy rainfall to 
portions of southern Mexico and Guatemala this week. Flooding and 
mudslides, especially in areas of steep terrain, are possible, 
especially from western Guatemala into portions of the Mexican 
states of Chiapas, Oaxaca, Veracruz, and Tabasco.


FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 15.1N  94.6W   30 KT  35 MPH
 12H  02/0600Z 15.5N  94.6W   35 KT  40 MPH
 24H  02/1800Z 15.9N  94.6W   45 KT  50 MPH
 36H  03/0600Z 16.5N  94.6W   45 KT  50 MPH...INLAND
 48H  03/1800Z 17.1N  94.6W   20 KT  25 MPH...POST-TROP/INLAND
 60H  04/0600Z...DISSIPATED

$$
Forecaster Blake