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Tropical Storm Sally Intermediate Advisory Number 10A
NWS National Hurricane Center Miami FL AL192020
100 AM CDT Mon Sep 14 2020
...SALLY FORECAST TO PRODUCE LIFE-THREATENING STORM SURGE,
HURRICANE-FORCE WINDS, AND HEAVY RAINFALL ALONG PORTIONS OF THE
NORTHERN GULF COAST STARTING LATER TODAY...
SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION
ABOUT 165 MI...265 KM S OF PENSACOLA FLORIDA
ABOUT 150 MI...240 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
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 Mississippi/Alabama Border
* Lake Pontchartrain and Lake Maurepas including metropolitan New
A Tropical Storm Warning is in effect for...
* Mississippi/Alabama Border to Indian Pass Florida
* Intracoastal City Louisiana to west of Morgan City
A Hurricane Watch is in effect for...
* Mississippi/Alabama Border to the Alabama/Florida Border
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
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 Hurricane Watch means that hurricane conditions are possible
within the watch area.
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 AM CDT (0600 UTC), the center of Tropical Storm Sally was
located near latitude 28.1 North, longitude 86.9 West. Sally is
moving toward the west near 12 mph (19 km/h). A slower west-
northwestward motion is expected soon, followed by a further
decrease in forward speed and a turn to the northwest tonight and
Tuesday. On the forecast track, the center of Sally will move over
the north-central Gulf of Mexico today, and approach the northern
Gulf Coast within the hurricane warning area tonight and on Tuesday.
Sally is expected to move slowly northward near the northern Gulf
Coast through Wednesday.
Maximum sustained winds are near 60 mph (95 km/h) with higher
gusts. Strengthening is expected over the next day or so, and Sally
is forecast to become a hurricane by tonight, with additional
strengthening possible before the center crosses the northern Gulf
Tropical-storm-force winds extend outward up to 125 miles (205 km)
from the center.
The estimated minimum central pressure based on data from the Air
Force Hurricane Hunters is 996 mb (29.42 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 including Lake
Ocean Springs to MS/AL Border...4-7 ft
Port Fourchon to Mouth of the Mississippi River...4-6 ft
Lake Pontchartrain and Lake Maurepas...4-6 ft
MS/AL Border to AL/FL Border including Mobile Bay...3-5 ft
Burns Point to Port Fourchon...1-3 ft
AL/FL Border to Chassahowitzka including Pensacola Bay,
Choctawhatchee Bay, and Saint Andrew Bay...1-3 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
WIND: Hurricane conditions are expected within the hurricane
warning area starting late today. Tropical storm conditions are
possible within the watch area during the next few hours, and are
expected within the warning area beginning this morning.
RAINFALL: Sally is expected to be a slow moving system resulting in
significant flash flooding for the central Gulf Coast today into
Wednesday. Sally is expected to produce rainfall of 8 to 16 inches
with isolated amounts of 24 inches over portions of the central Gulf
Coast from the western Florida Panhandle to southeast Louisiana
through the middle of the week. This rainfall will likely result in
new widespread minor to isolated major flooding on area rivers.
Sally is forecast to turn inland early Wednesday and track into the
Southeast with rainfall of 5 to 10 inches possible across much of
inland Mississippi and Alabama. Flash and urban flooding is
possible, as well as widespread minor to moderate flooding on some
rivers in Mississippi and Alabama.
Further heavy rain is then anticipated across portions of Tennessee,
northern Georgia and western North Carolina. 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 central and northern Florida through today.
This rainfall may produce flash and urban flooding and prolong high
flows and ongoing minor flooding on rivers across central Florida.
TORNADOES: The risk of isolated tornadoes will begin to increase
this afternoon and continue through Tuesday over parts of the
western Florida Panhandle, southern Alabama, southern Mississippi,
and southeast Louisiana.
SURF: Swells from Sally are affecting the west coast of the
Florida peninsula, the coast of the Florida Panhandle, and will
be spreading northwestward along the northern Gulf coast through
today. These swells are likely to cause life-threatening surf
and rip current conditions. Please consult products from your
local weather office.
Next complete advisory at 400 AM CDT.