BULLETIN
Hurricane Sally Intermediate Advisory Number 21A
NWS National Hurricane Center Miami FL AL192020
700 AM CDT Wed Sep 16 2020
…HURRICANE-FORCE WINDS OCCURRING IN PENSACOLA FLORIDA…
…CATASTROPHIC AND LIFE-THREATENING FLOODING LIKELY ALONG PORTIONS
OF THE NORTHERN GULF COAST…
SUMMARY OF 700 AM CDT…1200 UTC…INFORMATION
———————————————-
LOCATION…30.4N 87.6W
ABOUT 15 MI…25 KM NNE OF GULF SHORES ALABAMA
ABOUT 25 MI…40 KM WSW OF PENSACOLA FLORIDA
MAXIMUM SUSTAINED WINDS…100 MPH…155 KM/H
PRESENT MOVEMENT…NNE OR 20 DEGREES AT 3 MPH…6 KM/H
MINIMUM CENTRAL PRESSURE…967 MB…28.56 INCHES
WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:
The Storm Surge Warning has been discontinued west of Dauphin
Island, Alabama.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for…
* Dauphin Island Alabama to the Walton/Bay County Line Florida
A Hurricane Warning is in effect for…
* Mississippi/Alabama border to the Okaloosa/Walton County line
Florida
A Tropical Storm Warning is in effect for…
* East of the Okaloosa/Walton County line Florida to Indian Pass
Florida
* Mississippi/Alabama border to the Mouth of the Pearl River
A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
during the next 12 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 Hurricane Warning means that hurricane conditions are occurring
somewhere within the warning area. Preparations to protect life
and property should have been completed.
A Tropical Storm Warning means that tropical storm conditions are
occurring within the warning area.
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 700 AM CDT (1200 UTC), the center of the eye of Hurricane Sally
was located by NOAA Doppler weather radars near latitude 30.4 North,
longitude 87.6 West. Sally is moving toward the north-northeast near
3 mph (6 km/h). A north-northeastward to northeastward motion at a
slightly faster forward speed is expected later today and tonight,
followed by a faster northeastward motion on Thursday. On the
forecast track, the center of Sally will move across the extreme
western Florida panhandle and southeastern Alabama through early
Thursday, and move over central Georgia Thursday afternoon through
Thursday night.
Doppler weather radar data indicate that the maximum sustained
winds are near 100 mph (155 km/h) with higher gusts. Weakening is
expected as the center moves inland today and tonight.
Hurricane-force winds extend outward up to 40 miles (65 km) from
the center and tropical-storm-force winds extend outward up to 125
miles (205 km). A sustained wind of 74 mph (119 km/h) and a gust to
92 mph (148 km/h) were recently reported at the Pensacola Naval Air
Station in Pensacola, Florida.
The estimated minimum central pressure based on surface
observations is 967 mb (28.56 inches).
HAZARDS AFFECTING LAND
———————-
Key messages for Sally can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC,
and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml
RAINFALL: Through this afternoon, Sally will produce additional
rainfall totals of 8 to 12 inches with localized higher amounts
possible along and just inland of the central Gulf Coast from west
of Tallahassee, Florida to Mobile Bay, Alabama. Storm totals of 10
to 20 inches to isolated amounts of 35 inches is expected. Historic
and catastrophic flooding is unfolding. In addition, this rainfall
will lead to widespread moderate to major river flooding.
Sally is forecast to turn northeastward after making landfall today
and move across the Southeast through Friday, producing the
following rainfall totals:
Southern and central Alabama to central Georgia: 4 to 8 inches, with
isolated maximum amounts of 12 inches. Significant flash and urban
flooding is likely, as well as widespread minor to moderate flooding
on some rivers.
Western South Carolina into western and central North Carolina: 4 to
6 inches, with isolated maximum amounts of 9 inches. Widespread
flash and urban flooding is possible, as well as minor to moderate
river flooding.
Southeast Virginia: 2 to 5 inches, with isolated maximum amounts of
7 inches. Scattered flash and urban flooding is possible, as well as
scattered minor river flooding.
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…
AL/FL Border to Okaloosa/Walton County Line, FL including Pensacola
Bay and Choctawhatchee Bay…4-7 ft
Okaloosa/Walton County Line, FL to Walton Bay County Line, FL…2-4
ft
Dauphin Island, AL to AL/FL Border including Bon Secour Bay…2-4 ft
Walton Bay County Line, FL to Chassahowitzka, FL including Saint
Andrew Bay…1-3 ft
The deepest water will occur along the immediate coast in areas of
onshore winds, where the surge will be accompanied by large and
damaging 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.
WIND: Hurricane conditions are spreading onshore within the
hurricane warning area in Florida and Alabama. Tropical storm
conditions will continue in portions of the warning areas through
tonight.
TORNADOES: A few tornadoes may occur today and tonight across
portions of the Florida Panhandle, southern Alabama, and
southwestern Georgia.
SURF: Swells from Sally will continue to affect the coast from the
Florida Big Bend westward to southeastern Louisiana during the next
couple of days. These swells are likely to cause life-threatening
surf and rip current conditions. Please consult products from your
local weather office.