Hurricane Sally Advisory Number 21
NWS National Hurricane Center Miami FL AL192020
400 AM CDT Wed Sep 16 2020
...SALLY'S NORTHERN EYEWALL WITH HURRICANE CONDITIONS MOVING ACROSS
THE GULF COAST FROM PENSACOLA BEACH FLORIDA WESTWARD TO DAUPHIN
...CATASTROPHIC AND LIFE-THREATENING FLOODING LIKELY ALONG PORTIONS
OF THE NORTHERN GULF COAST...
SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION
ABOUT 50 MI...75 KM SSE OF MOBILE ALABAMA
ABOUT 40 MI...65 KM SW OF PENSACOLA FLORIDA
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 3 MPH...6 KM/H
MINIMUM CENTRAL PRESSURE...965 MB...28.50 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Hurricane Warning has been replaced with a Tropical Storm
Warning from the Mississippi/Alabama border westward to the Mouth
of the Pearl River.
The Tropical Storm Warning west of the Mouth of the Pearl River has
The Storm Surge Warning has been discontinued from the
Mississippi/Alabama border to Fort Morgan, including portions of
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* Fort Morgan Alabama to the Walton/Bay County Line Florida
A Hurricane Warning is in effect for...
* Mississippi/Alabama border to the Okaloosa/Walton County line
A Tropical Storm Warning is in effect for...
* East of the Okaloosa/Walton County line Florida to Indian Pass
* 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
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 400 AM CDT (0900 UTC), the center of the eye of Hurricane Sally
was located an Air Force Reserve Hurricane Hunter aircraft and NOAA
Doppler weather radars near latitude 30.1 North, longitude 87.7
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 approach the northern Gulf Coast
this morning, and make landfall in the hurricane warning area later
today. Sally is then expected to move inland across southeastern
Recent data from An Air Force Reserve reconnaissance aircraft and
the Mobile Alabama Doppler weather radar indicate that maximum
sustained winds are near 105 mph (165 km/h) with higher gusts.
Some slight increase in strength is possible before the center of
Sally's eye makes landfall later this morning. Rapid weakening is
expected after landfall occurs.
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 98 mph (157 km/h) and a gust to 116
mph (187 km/h) were recently measured by an elevated NOS CO-OP
observing station in Fort Morgan, Alabama. A University of
Florida weather tower located at Gulf Shores, Alabama, reported a
sustained wind speed of 75 mph (121 km/h) and a gust to 93 mph
(150 km/h). NOAA buoy 42012, located about 50 miles southeast of
Mobile, Alabama, recently reported a sustained wind of 71 mph (115
km/h) and a pressure of 970.9 mb inside the eastern portion of
The estimated minimum central pressure based on the buoy data is
965 mb (28.50 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
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...
Dauphin Island AL to Okaloosa/Walton County FL Line...4-7 ft
Pensacola Bay and Choctawhatchee Bay FL...4-7 ft
Mobile Bay...2-4 ft
Okaloosa/Walton County Line to Walton/Bay County line FL...2-4 ft
MS/AL Border to Dauphin Island AL...2-4 ft
Walton/Bay County line to Chassahowitzka FL including Saint Andrew
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
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
TORNADOES: A few tornadoes may occur today and tonight across
portions of the Florida Panhandle, southern Alabama, and
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.
Next intermediate advisory at 700 AM CDT.
Next complete advisory at 1000 AM CDT.
Hurricane Sally Discussion Number 21
NWS National Hurricane Center Miami FL AL192020
400 AM CDT Wed Sep 16 2020
There has been little change in Sally's convective structure during
the past few hours as seen in radar and satellite data. The initial
intensity of 90 kt is based on previous reconnaissance SFMR surface
wind data of 88 kt in the northeastern quadrant, along with average
Doppler radar values of 114 kt between 4500-5000 ft ASL, which
supports an equivalent surface wind speed of about 90 kt. The
reconnaissance aircraft has recently measured peak 700-mb
flight-level winds of 110 kt, but those winds may not be making it
down to the surface based on earlier buoy wind reports underneath
the eyewall. Although the northern eyewall has moved onshore between
Mobile Bay and Pensacola Bay, some slight strengthening is still
possible until the center of Sally's eye makes landfall later this
morning. Rapid weakening is forecast after the center moves inland,
and the system should become a remnant low in a couple of days.
This is consistent with the latest model guidance.
Radar and aircraft center fixes indicate that Sally's motion is
north-northeastward, or 020/03 kt. No significant changes were
required to the previous track forecast. The latest NHC model
guidance continues to show Sally moving slowly north-northeastward
this morning, and then turn northeastward with a gradual increase in
forward speed by tonight. That motion should then continue for the
next day or so. As Sally approaches the mid-latitude westerlies at
higher latitudes, the tropical cyclone should turn toward the
east-northeast with some slight increase in forward speed until it
becomes a dissipating remnant low near the southeastern U.S. coast
in 2-3 days. The official forecast is close to the latest corrected
dynamical model consensus, HCCA, prediction.
1. Historic and catastrophic flooding is unfolding along and just
inland of the coast from west of Tallahassee, Florida, to Mobile
Bay, Alabama. In addition, widespread moderate to major river
flooding is forecast. Significant flash and urban flooding, as well
as widespread minor to moderate river flooding, is likely across
inland portions Alabama into central Georgia. Widespread flash and
urban flooding is possible, as well as widespread minor to moderate
river flooding, across western South Carolina into western and
central North Carolina. Scattered flash and urban flooding is
possible, as well as scattered minor river flooding in southeast
2. Life-threatening storm surge is occurring along portions of the
coastline from Alabama to the western Florida Panhandle, including
Pensacola Bay and southern portions of Mobile Bay.
3. Hurricane conditions are expected this morning and then continue
into this afternoon within portions of the Hurricane Warning area
along the Mississippi and Alabama coastlines and the western Florida
FORECAST POSITIONS AND MAX WINDS
INIT 16/0900Z 30.1N 87.7W 90 KT 105 MPH
12H 16/1800Z 30.7N 87.2W 70 KT 80 MPH...INLAND
24H 17/0600Z 31.5N 86.3W 35 KT 40 MPH...INLAND
36H 17/1800Z 32.6N 84.7W 30 KT 35 MPH...INLAND
48H 18/0600Z 33.5N 82.4W 25 KT 30 MPH...INLAND
60H 18/1800Z 34.1N 79.5W 20 KT 25 MPH...POST-TROP/REMNT LOW