712
WTNT41 KNHC 081454
TCDAT1

Hurricane Delta Discussion Number 16
NWS National Hurricane Center Miami FL AL262020
1000 AM CDT Thu Oct 08 2020

Satellite imagery shows that Delta is better organized this
morning, with the center well embedded in a cold central dense
overcast and a hint of a eye developing in the overcast. Reports
from Air Force Reserve and NOAA Hurricane hunter aircraft indicate
that the central pressure has fallen to 968 mb inside a 35 n mi wide
eye, along with flight-level and SFMR winds that support an initial
intensity of 90 kt.

The initial motion remains northwestward or 305/12 kt. The track
forecast is reasonably straightforward. During the next 12-24 h,
Delta should turn to the north between a mid- to upper-level ridge
over the Florida Peninsula and eastern Gulf of Mexico and a mid- to
upper-level level trough over the U.S. Southern Plains. This
should be followed by a north-northeastward motion that is expected
to bring the center near or over the northern Gulf coast, most
likely in southwestern Louisiana, in about 36 h. After landfall,
the cyclone should move northeastward through the Lower Mississippi
and Tennessee Valleys along the southern edge of the mid-latitude
westerlies until it dissipates. The track guidance is very tightly
clustered in terms of direction, and the new forecast track has
only minor tweaks from the previous one.

Shear, sea surface temperature, and moisture conditions appear
favorable for strengthening during the next 12-24 h or so, and
based on this Delta is expected to regain major hurricane strength.
Rapid intensification cannot be ruled out, although the various
rapid intensification indices do not suggest a high chance, and
the first 24 h of the forecast is already above the intensity
guidance. The global models forecast strong southwesterly shear
developing over the hurricane during the last 12 h before landfall,
and based on this some weakening is forecast. Rapid weakening is
expected after landfall, with Delta forecast to degenerate to a
remnant low by 72 h and dissipate shortly after that. It should be
noted that the NHC 1-2 day intensity forecasts are subject to errors
of around 1 Saffir-Simpson category.

Delta is expected to grow in size as it approaches the Louisiana
coast. The NHC wind radii forecast again follows a consensus of the
global and hurricane regional models.

Key Messages:

1. Life-threatening storm surge is expected near and east of where
Delta makes landfall on Friday, and a Storm Surge Warning is in
effect from High Island, Texas, to Ocean Springs, Mississippi. The
highest inundation of 7 to 11 feet is expected somewhere between
Rockefeller Wildlife Refuge and Port Fourchon, Louisiana. Residents
in the warning area should promptly follow advice given by local
officials. The storm surge risk remains high despite the forecast
decrease in intensity before landfall since Delta is expected to
grow in size.

2. Hurricane-force winds are expected Friday afternoon and evening
somewhere within the Hurricane Warning area between High Island,
Texas, and Morgan City, Louisiana. Hurricane-force winds will also
spread inland across portions of southern Louisiana near the path of
Deltas center Friday evening and Friday night.

3. Significant flash flooding and minor to moderate river flooding
are likely in parts of Louisiana Friday and Saturday, with
additional flooding in portions of the central Gulf Coast into the
Lower Mississippi Valley.

FORECAST POSITIONS AND MAX WINDS

INIT 08/1500Z 24.0N 92.7W 90 KT 105 MPH
12H 09/0000Z 25.4N 93.6W 95 KT 110 MPH
24H 09/1200Z 27.5N 93.8W 100 KT 115 MPH
36H 10/0000Z 29.8N 93.1W 90 KT 105 MPH...ON THE COAST
48H 10/1200Z 32.4N 91.7W 45 KT 50 MPH...INLAND
60H 11/0000Z 34.0N 90.0W 30 KT 35 MPH...INLAND
72H 11/1200Z 35.6N 87.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 12/1200Z...DISSIPATED

$$
Forecaster Beven
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