Tropical Storm GAMMA Advisory Cts, 03.10.

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM

Tropical Depression Twenty-Five Discussion Number   2
NWS National Hurricane Center Miami FL       AL252020
400 PM CDT Fri Oct 02 2020

Convective banding features have become a little better defined
over the southern portion of the circulation, but otherwise the
system has not changed much in organization since earlier today.
The current intensity estimate remains at 30 kt in agreement with a
Dvorak estimate from TAFB, and scatterometer observations
from a few hours ago.  The SHIPS model output now shows some
south-southwesterly shear affecting the system during the next few
days.  Otherwise, the environment should favor at least gradual
strengthening, and the cyclone is likely to become a tropical storm
prior to moving near the Yucatan Peninsula.  The official intensity
forecast is within the range of most of the model guidance.

The initial motion estimate is the same as in the morning advisory,
315/8 kt.  The depression should move along the southwestern
periphery of a mid-tropospheric high pressure area for the next
couple of days, causing the cyclone to move on a northwestward to
north-northwestward heading.  Later in the forecast period, the
global models build a weak ridge across the northern half of the
Gulf of Mexico.  This should induce the cyclone to turn westward or
even a little south of west in 3-5 days.  The latest NHC forecast
lies between the simple and corrected dynamical model consensus
predictions, TVCA and HCCA, and is quite similar to the previous
official forecast.

At this time, the biggest threat from this slow-moving system is
rain and flooding, particularly near and over mountainous terrain.


KEY MESSAGES:

1. The system is expected to produce heavy rainfall that could
result in life-threatening flash flooding over portions of the
Yucatan Peninsula, far western Cuba and well away from the center in
the Mexican states of Campeche, Tabasco, and northern Chiapas.

2. The depression is forecast to become a tropical storm and bring
tropical storm conditions to portions of the Yucatan Peninsula on
Saturday, where a Tropical Storm Warning is in effect.


FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 18.8N  85.3W   30 KT  35 MPH
 12H  03/0600Z 19.5N  86.1W   35 KT  40 MPH
 24H  03/1800Z 20.5N  87.0W   40 KT  45 MPH
 36H  04/0600Z 21.6N  87.5W   40 KT  45 MPH
 48H  04/1800Z 22.3N  87.7W   40 KT  45 MPH
 60H  05/0600Z 22.5N  88.0W   45 KT  50 MPH
 72H  05/1800Z 22.5N  88.8W   50 KT  60 MPH
 96H  06/1800Z 22.5N  91.0W   50 KT  60 MPH
120H  07/1800Z 22.0N  92.5W   50 KT  60 MPH

$$
Forecaster Pasch