Official Discussion issued by the National Hurricane Center

Delta (AL262020) DATA RELEASED: 10/7/2020 10:00:00 PM UTC

Copy of official data

Hurricane Delta Discussion Number  14
NWS National Hurricane Center Miami FL       AL262020
1000 PM CDT Wed Oct 07 2020

Observations from an Air Force Reserve Unit Hurricane Hunter
aircraft indicate that Delta is gradually strengthening while it
moves over the open waters of the south-central Gulf of Mexico.
Based on a blend of adjusted flight-level and SFMR wind
measurements from the plane, the current intensity is set at 80 kt.
The cloud pattern of the hurricane continues to become better
organized on satellite images, with a growing Central Dense
Overcast, and convective banding features becoming better defined,
particularly over the northern semicircle of the circulation.
Additional intensification is likely while Delta moves through a
favorable environment during the next day or so, and the official
forecast is fairly close to the corrected consensus guidance, HCCA.
When the system moves into the northern Gulf, a decrease in oceanic
heat content, drier mid-tropospheric air, and increased vertical
shear should cause at least slow weakening.  The NHC intensity
forecast is above the numerical guidance in 36-48 hours.  It should
be noted that 1-2 day tropical cyclone intensity forecasts are
subject to errors of around 1 Saffir-Simpson category.

The global models show a further increase in the size of the
hurricane while it moves into the northern Gulf.  The official wind
radii forecasts are based on a consensus of these model predictions.

The latest center fixes from the Hurricane Hunters show a
west-northwestward motion, at about 300/15 kt.  Delta should turn
toward the north-northwest and north over the next 36 hours or so
while moving around the western periphery of a subtropical high
pressure system centered over Florida.  When the hurricane moves
into the northern Gulf of Mexico on Friday, Delta should turn
toward the north-northeast on the southeastern side of a
mid-tropospheric shortwave over the southern United States.  The
official track forecast is close to both the simple and corrected
dynamical model consensus predictions, TVCA and HCCA, respectively.
These objective aids are in close agreement with one another.

Based on the official forecast, it is time to issue storm surge and
hurricane warnings for a portion of the northern Gulf of Mexico

Key Messages:

1. Delta is expected to grow in size as it approaches the northern
Gulf Coast, where life-threatening storm surge and dangerous
hurricane-force winds are likely beginning Friday, particularly for
portions of the Louisiana coast.  Storm Surge and Hurricane Warnings
are in effect, and residents in these areas should follow advice
given by local officials and rush preparedness actions to

2. Flash, urban, small stream and minor to isolated moderate river
flooding is likely Friday and Saturday from portions of the central
Gulf Coast into portions of the Lower to Middle Mississippi Valley.
As Delta moves farther inland, additional heavy rainfall is expected
in the Ohio Valley and Mid Atlantic this weekend.


INIT  08/0300Z 22.5N  90.9W   80 KT  90 MPH
12H  08/1200Z 23.7N  92.2W   95 KT 110 MPH
24H  09/0000Z 25.4N  93.4W  105 KT 120 MPH
36H  09/1200Z 27.5N  93.5W  100 KT 115 MPH
48H  10/0000Z 30.0N  92.7W   85 KT 100 MPH
60H  10/1200Z 32.4N  91.5W   35 KT  40 MPH...INLAND
72H  11/0000Z 34.2N  89.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
96H  12/0000Z 37.5N  85.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  13/0000Z...DISSIPATED

Forecaster Pasch