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Tropical Storm Irma Advisory Number 50
NWS National Hurricane Center Miami FL AL112017
1100 AM EDT Mon Sep 11 2017
...IRMA GRADUALLY WEAKENING WHILE MOVING OVER NORTHERN FLORIDA ...
SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
ABOUT 70 MI...115 KM E OF TALLAHASSEE FLORIDA
ABOUT 85 MI...135 KM N OF CEDAR KEY FLORIDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Storm Surge Warning has been discontinued from Bonita Beach
The Tropical Storm Warning has been discontinued for Lake
The Tropical Storm Warning has been discontinued from the
Volusia/Brevard County line southward.
The Tropical Storm Warning has been discontinued south of Anclote
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* South Santee River southward to the Flagler/Volusia County line
* North of Bonita Beach to the Ochlockonee River
* Tampa Bay
A Tropical Storm Warning is in effect for...
* Anclote River to the Okaloosa/Walton County Line
* North of the Volusia/Brevard County line to the South Santee
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.
Interests elsewhere in the southeastern United States should monitor
the progress of Irma.
For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
DISCUSSION AND 48-HOUR OUTLOOK
At 1100 AM EDT (1500 UTC), the center of Tropical Storm Irma was
located near latitude 30.3 North, longitude 83.1 West. Irma is
moving toward the north-northwest near 17 mph (28 km/h), and this
motion is expected to continue through Tuesday. On the forecast
track, the center of Irma will move into southwestern Georgia later
today, and move into eastern Alabama Tuesday morning.
Maximum sustained winds have decreased to near 65 mph (100 km/h)
with higher gusts. Continued slow weakening is forecast, and Irma
is likely to become a tropical depression on Tuesday.
Irma remains a large tropical cyclone. Tropical-storm-force winds
extend outward up to 415 miles (665 km) from the center. A 60 mph
(96 km/h) sustained wind and a 69 mph (111 km/h) gust was recently
reported at the National Data Buoy Center C-MAN station in St.
The estimated minimum central pressure is 975 mb (28.80 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 is
expected to reach the following HEIGHTS ABOVE GROUND if the peak
surge occurs at the time of high tide...
Clearwater Beach to Ochlockonee River...4 t 6 ft
Anna Maria Island to Clearwater, including Tampa Bay...2 to 4 ft
Captiva to Anna Maria Island...3 to 5 ft
Bonita Beach to Captiva...2 to 4 ft
South Santee River to Fernandina Beach...4 to 6 ft
Fernandina Beach to Flagler/Volusia County line, including the
St. Johns River...3 to 5 ft
The deepest water will occur along the immediate coast in areas of
onshore winds, where the surge will be accompanied by large and
destructive 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: Tropical storm conditions will continue across portions of the
central and northern Florida peninsula and southern Georgia.
Tropical storm conditions are spreading into the eastern Florida
Panhandle. Tropical storm conditions are also expected to spread
northward across the remainder of the warning area through today.
Rainfall: Irma is expected to produce the following rain
accumulations through Wednesday:
Northern Florida peninsula and southern Georgia: additional 3 to 6
inches with storm total amounts of 8 to 15 inches.
Central Georgia, eastern Alabama and southern South Carolina: 3 to
inches, isolated 10 inches.
Central Florida Panhandle, western Alabama, northern Mississippi,
southern Tennessee, northern Georgia, northern South Carolina and
western North Carolina: 2 to 4 inches.
The precipitation threat for most of the Florida peninsula, except
for the northernmost portions, has diminished. Scattered showers
are expected to produce additional rainfall amounts of less than an
inch across most of the Florida peninsula during Monday.
TORNADOES: A few tornadoes are possible today and tonight near the
Georgia and South Carolina coasts.
SURF: Swells generated by Irma are affecting the southeast coast of
the United States. 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 200 PM EDT.
Next complete advisory at 500 PM EDT.