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…GORDON LASHING SOUTH FLORIDA WITH TROPICAL-STORM-FORCE WINDS AND
HEAVY RAINS…
…STORM SURGE WARNING AND HURRICANE WATCH ISSUED FOR PORTIONS OF
THE CENTRAL GULF COAST…

SUMMARY OF 1100 AM EDT…1500 UTC…INFORMATION
———————————————–
LOCATION…25.3N 81.3W
ABOUT 60 MI…95 KM WNW OF KEY LARGO FLORIDA
ABOUT 50 MI…80 KM SSE OF MARCO ISLAND FLORIDA
MAXIMUM SUSTAINED WINDS…45 MPH…75 KM/H
PRESENT MOVEMENT…WNW OR 300 DEGREES AT 16 MPH…26 KM/H
MINIMUM CENTRAL PRESSURE…1009 MB…29.80 INCHES

WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:

A Storm Surge Warning has been issued from Shell Beach, Louisiana,
to the Mississippi-Alabama border.

The Storm Surge Watch has been extended eastward from the
Mississippi-Alabama border to Navarre, Florida.

A Hurricane Watch has been issued from the Mouth of the Pearl River
to the Alabama-Florida Border.

The Tropical Storm Warning has been extended eastward to the
Okaloosa-Walton County Line.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for…
* Shell Beach to Mississippi-Alabama border

A Storm Surge Watch is in effect for…
* West of Shell Beach to the Mouth of the Mississippi River
* East of the Mississippi-Alabama border to Navarre

A Hurricane Watch is in effect for…
* Mouth of the Pearl River to the Alabama-Florida Border

A Tropical Storm Warning is in effect for…
* Golden Beach to Bonita Beach
* Craig Key to Ocean Reef, including Florida Bay
* Okaloosa-Walton County Line westward to east of Morgan City,
Louisiana, including Lake Pontchartrain and Lake Maurepas

A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
during the next 36 hours in the indicated locations. For a
depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov. This is a life-threatening situation. Persons
located within these areas should take all necessary actions to
protect life and property from rising water and the potential for
other dangerous conditions. Promptly follow evacuation and other
instructions from local officials.

A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations.

A Hurricane Watch means that hurricane conditions are possible
within the watch area. A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
dangerous.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning areas.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.

DISCUSSION AND OUTLOOK
———————-
At 1100 AM EDT (1500 UTC), the center of Tropical Storm Gordon was
located near latitude 25.3 North, longitude 81.3 West. Gordon is
moving toward the west-northwest near 16 mph (26 km/h) and a west-
northwestward to northwestward motion is expected over the next
72 hours. On the forecast track, the center of Gordon will emerge
over the southeastern Gulf of Mexico by early afternoon, reach
the warning area along the central Gulf Coast by late Tuesday or
Tuesday night, and move inland over the lower Mississippi Valley on
Wednesday.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
strengthening is forecast during the next 36 to 48 hours, and
Gordon could be near hurricane strength when it makes landfall
along the central Gulf Coast.

Tropical-storm-force winds extend outward up to 45 miles (75 km)
from the center.

The estimated minimum central pressure is 1009 mb (29.80 inches).

HAZARDS AFFECTING LAND
———————-
STORM SURGE: The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline. The water could
reach the following heights above ground somewhere in the indicated
areas if the peak surge occurs at the time of high tide…

Shell Beach to the Mississippi-Alabama border…3 to 5 ft.
Navarre Florida to the Mississippi-Alabama border…2 to 4 ft.
Shell Beach to the Mouth of Mississippi River…2 to 4 ft.
Mouth of the Mississippi River to the Louisiana-Texas border…1 to
2 ft.

The deepest water will occur along the immediate coast near and to
the east of the landfall location, where the surge will be
accompanied by large waves. Surge-related flooding depends on the
relative timing of the surge and the tidal cycle, and can vary
greatly over short distances. For information specific to your area,
please see products issued by your local National Weather Service
forecast office.

RAINFALL: Gordon is expected to produce total rain accumulations of
2 to 4 inches over the central and northwestern Bahamas, the Florida
Keys, and South Florida through early Tuesday. Isolated maximum
amounts of 8 inches are possible over the southern Florida
peninsula.

Gordon is expected to produce total rain accumulations of 4 to 6
inches over southern Alabama, southern Mississippi and Louisiana,
with isolated maximum amounts of 8 inches through early Thursday.

These rainfall amounts may cause flash flooding.

WIND: Tropical storm conditions will continue through the
afternoon in the warning areas across South Florida and the Florida
Keys. Tropical storm conditions are expected within portions of the
central Gulf Coast warning area by late Tuesday, with hurricane
conditions possible late Tuesday or Tuesday night in the hurricane
watch area.

TORNADOES: A couple of tornadoes are possible through tonight
across the southern and west-central Florida Peninsula.

Tropical Storm Gordon Discussion Number 5
NWS National Hurricane Center Miami FL AL072018
1100 AM EDT Mon Sep 03 2018

Surface observations from the Florida Keys and southeast Florida,
along with Doppler velocity data from the Miami radar, indicate that
Gordon has continued to become organized this morning. The center
of the cyclone passed over Key Largo between 1100-1200 UTC,
producing a west wind in Islamorada and also at an observing site
in Florida Bay. Doppler velocity data and surface observations
support an intensity of 40 kt for this advisory. An Air Force
Reserve Unit reconnaissance aircraft is currently investigating
Gordon.

The initial motion estimate is 300/14 kt. The latest model
guidance has shifted slightly to the right, but this is likely due
to the more northerly initial position. Other than that, the models
remain tightly packed and agree on a general west-northwestward to
northwestward motion for the next 48 hours right up until landfall
as the strong ridge to the north of Gordon moves little. The new NHC
forecast track was adjusted a little to the right of the previous
advisory track, but not as far to the east as some of the model
guidance out of respect for the reliable ECMWF deterministic run,
which is located on the southern edge of the guidance and shows
landfall near the mouth of the Mississippi River, a solution that is
also supported by the new 0600Z short-range UKMET model run.

Gordon’s appearance in both radar and satellite imagery has
continued to improve over the past several hours. The GFS- and
ECMWF-based SHIPS models indicate that westerly to northwesterly
vertical wind shear of about 10 kt is allegedly affecting Gordon,
but there are no indications of that in satellite imagery that I
can see. The cirrus outflow has continued to expand in all
quadrants, so the analyzed westerly shear is likely an artifact of
the small circulation being positioned so close to the strong trough
located its west. Since Gordon will be moving over sea-surface
temperatures near 30 deg C during the next 36-48 hours, and be near
or underneath an upper-level anticyclone, steady strengthening seems
likely. It is possible that Gordon could peak as a Category 1
hurricane after 36 hours, just before landfall occurs. For that
reason, a Hurricane Watch has been issued for portions of the
central Gulf Coast. The new intensity forecast is above the previous
advisory, and is close to a blend of the consensus models
HCCA, FSSE, and IVCN.

Key Messages:

1. Gordon will bring heavy rainfall and tropical storm conditions
to portions of South Florida and the Florida Keys today and a
Tropical Storm Warning remains in effect for these areas.

2. Gordon is expected to bring life-threatening storm surge to
portions of the central Gulf Coast and a Storm Surge Warning has
been issued from the Mouth of the Pearl River to the Mississippi-
Alabama border. Residents in these areas should listen to advice
from their local officials and all preparations to protect life
and property should be rushed to completion.

3. A Tropical Storm Warning and Hurricane Watch are in effect for
portions of the central Gulf Coast. Tropical storm conditions are
expected to reach those areas late Tuesday, with hurricane
conditions possible in the watch area.

4. Heavy rainfall from Gordon will affect southern Alabama, southern
Mississippi and Louisiana, where totals could reach as high as 8
inches. This rainfall could cause flash flooding.

FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 25.3N 81.3W 40 KT 45 MPH
12H 04/0000Z 26.5N 83.4W 45 KT 50 MPH
24H 04/1200Z 28.1N 86.0W 50 KT 60 MPH
36H 05/0000Z 29.9N 88.4W 60 KT 70 MPH
48H 05/1200Z 31.3N 90.3W 40 KT 45 MPH…INLAND
72H 06/1200Z 33.9N 93.2W 25 KT 30 MPH…INLAND
96H 07/1200Z 34.8N 94.9W 20 KT 25 MPH…INLAND
120H 08/1200Z 37.6N 95.1W 20 KT 25 MPH…POST-TROP/REMNT LOW

NEXT ADVISORY
————-
Next intermediate advisory at 200 PM EDT.
Next complete advisory at 500 PM EDT.