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Tropical Storm Sally Intermediate Advisory Number 6A
NWS National Hurricane Center Miami FL AL192020
200 AM EDT Sun Sep 13 2020
...SALLY COULD PRODUCE LIFE-THREATENING STORM SURGE, HURRICANE-
FORCE WINDS AND HEAVY RAINFALL ALONG PORTIONS OF THE NORTHERN GULF
COAST STARTING ON MONDAY...
SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION
ABOUT 80 MI...130 KM WSW OF PORT CHARLOTTE FLORIDA
ABOUT 385 MI...620 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Watch is in effect for...
* Mouth of the Mississippi River to the Alabama/Florida Border
* Lake Pontchartrain, Lake Maurepas, and Lake Borgne
* Mobile Bay
A Hurricane Watch is in effect for...
* Grand Isle Louisiana to the Alabama/Florida border
* Lake Pontchartrain and Lake Maurepas including metropolitan New
A Tropical Storm Watch is in effect for...
* Alabama/Florida Border to Ochlockonee River Florida
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 during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
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
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area within the next 48 hours.
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 200 AM EDT (0600 UTC), the center of Tropical Storm Sally was
located near latitude 26.7 North, longitude 83.4 West. Sally is
moving toward the west-northwest near 8 mph (13 km/h), and a
west-northwestward or northwestward motion is expected through
Monday. A decrease in forward speed and a turn toward the north-
northwest is forecast on Tuesday. On the forecast track, the center
of Sally will move over the southeastern and eastern Gulf of Mexico
today, move over the north-central Gulf of Mexico Sunday night and
Monday, and approach the north-central Gulf Coast within the
hurricane watch area late Monday and Tuesday.
Air Force Reserve Hurricane Hunter aircraft and buoy data indicate
that maximum sustained winds have increased to near 45 mph (75 km/h)
with higher gusts. Further strengthening is expected over the next
couple of days, and Sally is forecast to become a hurricane on
Monday, with some additional strengthening possible through early
Tropical-storm-force winds extend outward up to 80 miles (130 km),
mainly to the southeast of the center. A wind gust of 41 mph (67
km/h) was recently reported on Sanibel Island, Florida.
The estimated minimum central pressure is 1003 mb (29.62 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.
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
Ocean Springs, MS to MS/AL Border...4-6 ft
MS/AL Border to AL/FL Border, including Mobile Bay...2-4 ft
Lake Pontchartrain and Lake Maurepas...2-4 ft
AL/FL Border to Chassahowitzka, FL, including Pensacola Bay,
Choctawhatchee Bay, and Saint Andrew Bay...1-3 ft
The deepest water will occur along the immediate coast near and to
the right of the landfall location, 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 possible within the hurricane watch
area by early Tuesday, with tropical storm conditions possible
within the watch areas by Monday.
Wind gusts to tropical storm force are possible across the lower
Florida Keys overnight.
RAINFALL: Sally is expected to produce additional rainfall amounts
of 2 to 4 inches with locally higher amounts possible over southern
Florida and the Florida Keys through today. Rainfall amounts of
2 to 4 inches with isolated amounts of 6 inches are expected along
the west coast of Florida through today. This rainfall will
produce flash and urban flooding across southern Florida and prolong
high flows and ongoing minor flooding on rivers across central
Sally is expected to produce rainfall amounts of 5 to 10 inches
across the Florida Panhandle, and 6 to 12 inches with isolated
amounts of 18 inches over the Central Gulf Coast from Sunday into
the middle of next week, with 3 to 6 inch rainfall amounts possible
over inland portions of Mississippi and Alabama. Sally is expected
to be a slow moving system that will continue to produce heavy
rainfall and considerable flooding near the central Gulf Coast
through the middle of next week. Flash, urban, and rapid onset
flooding along small streams and minor to moderate flooding on
rivers is likely.
SURF: Swells will spread northward along the west-central coast of
Florida and reach the Florida Panhandle and the northern Gulf Coast
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.
TORNADOES: A tornado is possible overnight along the south Florida
Next complete advisory at 500 AM EDT.