WTNT31 KNHC 112352
Tropical Storm Irma Intermediate Advisory Number 51A
NWS National Hurricane Center Miami FL AL112017
800 PM EDT Mon Sep 11 2017
…IRMA WEAKENING BUT HEAVY RAINS CONTINUE ACROSS THE SOUTHEASTERN
SUMMARY OF 800 PM EDT…0000 UTC…INFORMATION
ABOUT 55 MI…85 KM SE OF COLUMBUS GEORGIA
ABOUT 120 MI…195 KM S OF ATLANTA GEORGIA
MAXIMUM SUSTAINED WINDS…45 MPH…75 KM/H
PRESENT MOVEMENT…NNW OR 330 DEGREES AT 16 MPH…26 KM/H
MINIMUM CENTRAL PRESSURE…986 MB…29.12 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Storm Surge Warning has been discontinued from north of
Clearwater Beach to the Aucilla River.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for…
* North of Fernandina Beach to the South Santee River
A Tropical Storm Warning is in effect for…
* North of Altamaha Sound to the South Santee River
A Storm Surge Warning means there is a danger of life-threatening
inundation from rising water moving inland from the coastline,
in this case during the next 12 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, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
DISCUSSION AND 48-HOUR OUTLOOK
At 800 PM EDT (0000 UTC), the center of Tropical Storm Irma was
located near latitude 31.9 North, longitude 84.4 West. Irma is
moving toward the north-northwest near 16 mph (26 km/h), and a turn
toward the northwest is expected by Tuesday morning. On the
forecast track, the center of Irma will continue to move over
southwestern Georgia tonight and move into Alabama on Tuesday.
Maximum sustained winds have decreased to near 45 mph (75 km/h)
with higher gusts. Continued weakening is forecast, and Irma is
likely to become a tropical depression on Tuesday.
Tropical-storm-force winds extend outward up to 415 miles (665 km)
from the center.
The estimated minimum central pressure based on surface observations
is 986 mb (29.12 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…
Bonita Beach to Ochlockonee River, including Tampa Bay…1 to 3 ft
South Santee River to North of Fernandina Beach…2 to 4 ft
Fernandina Beach to Flagler/Volusia County line, including the St.
Johns River…1 to 3 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 are expected in portions of the
warning area into tonight.
Rainfall: Irma is expected to produce the following rain
accumulations through Wednesday:
South Carolina and north-central Georgia and Alabama into the
southern Appalachians…3 to 6 inches with isolated 10 inches.
Northern Mississippi and southern portions of Tennessee and North
Carolina…2 to 4 inches.
TORNADOES: Isolated tornadoes are possible tonight along the South
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 complete advisory at 1100 PM EDT.