BULLETIN
Hurricane Sally Intermediate Advisory Number 13A
NWS National Hurricane Center Miami FL AL192020
100 PM CDT Mon Sep 14 2020
…SALLY MEANDERING OVER THE NORTH-CENTRAL GULF OF MEXICO…
…EXPECTED TO RESUME A SLOW WEST-NORTHWESTWARD MOTION…
SUMMARY OF 100 PM CDT…1800 UTC…INFORMATION
———————————————-
LOCATION…28.7N 87.1W
ABOUT 125 MI…200 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 160 MI…260 KM SE OF BILOXI MISSISSIPPI
MAXIMUM SUSTAINED WINDS…90 MPH…150 KM/H
PRESENT MOVEMENT…WNW OR 285 DEGREES AT 7 MPH…11 KM/H
MINIMUM CENTRAL PRESSURE…986 MB…29.12 INCHES
WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:
None
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for…
* Port Fourchon Louisiana to the Alabama/Florida Border
* Lake Pontchartrain, Lake Maurepas, and Lake Borgne
* Mobile Bay
A Hurricane Warning is in effect for…
* Morgan City Louisiana to the Alabama/Florida Border
* Lake Pontchartrain and Lake Maurepas including metropolitan New
Orleans
A Tropical Storm Warning is in effect for…
* Alabama/Florida Border to Indian Pass Florida
* Intracoastal City Louisiana to west of Morgan City
A Tropical Storm Watch is in effect for…
* Indian Pass to Ochlockonee River Florida
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 Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. Preparations to protect life
and property should be rushed to completion.
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch 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 100 PM CDT (1800 UTC), the center of Hurricane Sally was located
near by NOAA and Air Force Reserve Hurricane Hunter aircraft near
latitude 28.7 North, longitude 87.1 West. Sally has been meandering
over the north-central Gulf of Mexico today, but a west-northwest
near 7 mph (11 km/h) should resume later today. A decrease in
forward speed and a turn toward the northwest is forecast tonight
and a northward turn is expected sometime on Tuesday. On the
forecast track, the center of Sally will move over the north-central
Gulf of Mexico today, approach southeastern Louisiana tonight, and
make landfall in the hurricane warning area on Tuesday or Tuesday
night. Afterward, Sally is expected to move slowly
north-northeastward near the northern Gulf Coast through Wednesday.
Maximum sustained winds are near 90 mph (150 km/h) with higher
gusts. Additional strengthening is forecast during the next day or
so, and Sally is expected to be a dangerous hurricane when it moves
onshore along the north-central Gulf coast.
Hurricane-force winds extend outward up to 25 miles (35 km) from
the center and tropical-storm-force winds extend outward up to 125
miles (205 km).
The latest minimum central pressure estimated from reconnaissance
aircraft data is 986 mb (29.12 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
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…
Mouth of the Mississippi River to Ocean Springs, MS including Lake
Borgne…7-11 ft
Ocean Springs, MS to Dauphin Island, AL…6-9 ft
Mobile Bay…5-8 ft
Lake Pontchartrain and Lake Maurepas…3-5 ft
Dauphin Island, AL to AL/FL Border…4-6 ft
Port Fourchon, LA to Mouth of the Mississippi River…2-4 ft
AL/FL Border to Chassahowitzka, FL including Pensacola Bay,
Choctawhatchee Bay, and Saint Andrew Bay…1-3 ft
Burns Point, LA to Port Fourchon, LA…1-2 ft
Overtopping of local levees outside of the Hurricane and Storm
Damage Risk Reduction System is possible where local inundation
values may be higher than those shown above.
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 expected to begin within the
hurricane warning area tonight. Tropical storm conditions are
possible within the watch area today, and are expected to begin
within the warning area later today.
RAINFALL: Sally is expected to be a slow moving system as it
approaches land, producing 8 to 16 inches of rainfall with isolated
amounts of 24 inches over portions of the central Gulf Coast from
the western Florida Panhandle to far southeast Louisiana through the
middle of the week. Life-threatening flash flooding is likely. In
addition, this rainfall will likely lead to widespread minor to
isolated major flooding on area rivers.
Sally is forecast move farther inland early Wednesday and track
into the Southeast with rainfall of 6 to 12 inches possible across
portions of inland southeast Mississippi and Alabama. Significant
flash and urban flooding is likely, as well as widespread minor to
moderate flooding on some rivers.
Further heavy rain is then anticipated across portions of eastern
Tennessee, northern Georgia and western Carolinas Thursday into
Friday. Flash, urban, and minor river flooding is possible across
this region.
Outer bands of Sally are expected to produce additional rainfall of
1 to 3 inches across the Florida peninsula today. This rainfall may
produce flash and urban flooding and prolong high flows and ongoing
minor flooding on rivers across central Florida.
TORNADOES: A tornado or two may occur this afternoon through
Tuesday over coastal areas of the Florida Panhandle, Mississippi,
Alabama, and extreme southeastern Louisiana.
SURF: Swells from Sally will continue to affect areas from the
west coast of the Florida peninsula westward through the coast of
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.