BULLETIN
Tropical Storm Sally Advisory Number 5
NWS National Hurricane Center Miami FL AL192020
500 PM EDT Sat Sep 12 2020
…SALLY MOVING SLOWLY AWAY FROM EXTREME SOUTH FLORIDA…
…STORM SURGE AND HURRICANE WATCHES ISSUED FOR PORTIONS OF THE
NORTHERN GULF COAST…
SUMMARY OF 500 PM EDT…2100 UTC…INFORMATION
———————————————-
LOCATION…25.7N 81.9W
ABOUT 30 MI…45 KM SSW OF NAPLES FLORIDA
MAXIMUM SUSTAINED WINDS…40 MPH…65 KM/H
PRESENT MOVEMENT…W OR 280 DEGREES AT 7 MPH…11 KM/H
MINIMUM CENTRAL PRESSURE…1004 MB…29.65 INCHES
WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:
A Storm Surge Watch is in effect from the Mouth of the Mississippi
River to the Alabama/Florida Border, including Lake Pontchartrain,
Lake Maurepas, Lake Borgne, and Mobile Bay.
A Hurricane Watch is in effect from Grand Isle Louisiana to the
Alabama/Florida border, including Lake Pontchartrain, Lake
Maurepas, and metropolitan New Orleans.
The Tropical Storm watch has been extended westward from the
Okaloosa/Walton County Line to the Alabama/Florida Border.
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
Orleans
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
hurricanes.gov.
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
dangerous.
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 500 PM EDT (2100 UTC), the center of Tropical Storm Sally was
located near latitude 25.7 North, longitude 81.9 West. Sally is
moving toward the west near 7 mph (11 km/h), and a turn toward the
west-northwest is expected tonight. A west-northwestward or
northwestward motion is then expected during the next couple of
days. On the forecast track, the center is forecast to move over
the southeastern and eastern Gulf of Mexico tonight and Sunday, and
then move over the north-central Gulf of Mexico Sunday night and
Monday.
Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Strengthening is expected over the next couple of days, and Sally is
forecast to become a hurricane on Monday.
Tropical-storm-force winds extend outward up to 80 miles (130 km)
from the center.
The estimated minimum central pressure is 1004 mb (29.65 inches).
HAZARDS AFFECTING LAND
———————-
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…6-9 ft
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 area by Monday.
Wind gusts to tropical-storm force are possible across the
southern portion of the Florida peninsula through this evening,
especially over the Florida Keys.
RAINFALL: Sally is expected to produce additional rainfall amounts
of 2 to 4 inches over southern Florida and the Florida Keys through
tonight. Rainfall amounts of 2 to 4 inches with isolated amounts
of 6 inches are expected along the west coast of Florida through
Sunday. This rainfall will produce flash and urban flooding across
southern Florida and prolong high flows and ongoing minor flooding
on rivers across central Florida.
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. 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 are expected to 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 or two is possible through tonight over south
Florida.