Official Discussion issued by the National Hurricane Center

Twenty-Six (AL262020) DATA RELEASED: 10/5/2020 3:00:00 AM UTC

Copy of official data

Tropical Depression Twenty-Six Discussion Number   2
NWS National Hurricane Center Miami FL       AL262020
1100 PM EDT Sun Oct 04 2020

Satellite data indicate that the disturbance just south of Jamaica 
has become better organized this evening.  Microwave and shortwave 
infrared images indicate that the center is now well defined, and 
deep convection has been persisting near and to the south of the 
center.  Based on this data, the system now meets the criteria to be 
considered a tropical depression.  The initial intensity remains 30 
kt for this advisory.

The depression is currently moving west-northwestward at 8 kt on the
southern side of an Atlantic subtropical ridge.  A continued
west-northwest to northwest motion at about the same forward speed
is expected during the next 24 to 36 hours, taking the system across
the Cayman Islands and toward western Cuba.  Around the time the
depression is expected to be near western Cuba, the models show it
accelerating northwestward as it moves in the faster flow between
the ridge and Tropical Storm Gamma.  This motion should bring the
tropical cyclone into the southern Gulf of Mexico Tuesday night or
early Wednesday. Later on, a notable slow down and a turn to the
north is forecast to occur late in the week when the depression will
likely be approaching the northern Gulf coast.  This change in the
forecast motion is a result of the ridge weakening and a trough
approaching the cyclone from the west.  The models are in relatively
good agreement, which is surprising since they often diverge for
weak systems, and the NHC track forecast lies near the middle of the
guidance envelope.

There is currently some northeasterly shear affecting the
depression, but the models all show the shear lessening by tomorrow
and remaining fairly light for the next few days.  These improving
upper-level wind conditions combined with a moist air mass and warm
waters should allow for at least steady strengthening during the
next few days.  By late in the week, when the storm is forecast to
approach the U.S. Gulf coast, there could be an increase in
southerly or southwesterly shear, which could limit additional
strengthening by that time.  The NHC intensity forecast lies fairly
close to the IVCN and HCCA consensus aids, and shows the depression
becoming a hurricane near western Cuba with additional strengthening
over the Gulf of Mexico.

Users are reminded that the average 4- and 5-day NHC track forecast
errors are about 160 to 200 miles at those time periods,

Key Messages:

1. Tropical storm conditions are expected in the Cayman Islands
beginning late Monday, and a Tropical Storm Warning is in

2. Dangerous storm surge and hurricane conditions are possible in
portions of western Cuba and the Isle of Youth by Tuesday
afternoon, and a Hurricane Watch is in effect.

3. Heavy rainfall will affect portions of Hispaniola, Jamaica, the
Cayman Islands, and western Cuba during the next few days and could
lead to life-threatening flash floods and mudslides.

4. The system is forecast to approach the northern Gulf Coast late
this week as a hurricane. While there is large uncertainty in the
track and intensity forecasts at these time ranges, there is a risk
of dangerous storm surge, wind, and rainfall hazards along the coast
from Louisiana to the western Florida Panhandle. Residents in these
areas should monitor the progress of the system and check for
updates to the forecast during the week.


INIT  05/0300Z 17.0N  77.3W   30 KT  35 MPH
12H  05/1200Z 17.4N  78.3W   35 KT  40 MPH
24H  06/0000Z 18.3N  79.8W   40 KT  45 MPH
36H  06/1200Z 20.0N  81.9W   50 KT  60 MPH
48H  07/0000Z 22.2N  84.4W   65 KT  75 MPH
60H  07/1200Z 24.1N  87.0W   80 KT  90 MPH
72H  08/0000Z 25.4N  88.8W   85 KT 100 MPH
96H  09/0000Z 27.2N  90.4W   90 KT 105 MPH
120H  10/0000Z 30.0N  89.9W   75 KT  85 MPH...INLAND

Forecaster Cangialosi