ZCZC MIATCPAT1 ALL
TTAA00 KNHC DDHHMM
Tropical Storm Irma Intermediate Advisory Number 49A
NWS National Hurricane Center Miami FL AL112017
800 AM EDT Mon Sep 11 2017
...IRMA WEAKENS TO A TROPICAL STORM BUT STILL PRODUCING SOME WIND
GUSTS TO NEAR HURRICANE FORCE...
SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION
ABOUT 30 MI...50 KM NNE OF CEDAR KEY FLORIDA
ABOUT 105 MI...170 KM NNW OF TAMPA FLORIDA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.64 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Storm Surge Warning is discontinued from south of the
Flagler/Volusia County line to Jupiter Inlet.
The Hurricane Warning from Sebastian Inlet to Fernandina Beach is
changed to a Tropical Storm Warning.
The Hurricane Warning from Anclote River to Indian Pass is changed
to a Tropical Storm Warning.
The Hurricane Watch from north of Fernandina Beach to Edisto Beach
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
* Cape Sable northward to the Ochlockonee River
* Tampa Bay
A Tropical Storm Warning is in effect for...
* Bonita Beach to the Okaloosa/Walton County Line
* Jupiter Inlet to the South Santee River
* Lake Okeechobee
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 800 AM EDT (1200 UTC), the center of Tropical Storm Irma was
located near latitude 29.5 North, longitude 82.9 West. Irma is
moving toward the north-northwest near 18 mph (30 km/h) and this
motion is expected to continue through Tuesday. On the forecast
track, the center of Irma will move near the northwestern coast of
the Florida Peninsula this morning, cross the eastern Florida
Panhandle into southern Georgia this afternoon, and move through
southwestern Georgia and eastern Alabama tonight and Tuesday.
Maximum sustained winds have decreased to near 70 mph (110 km/h)
with higher gusts. Additional slow weakening is forecast, and Irma
is expected to weaken to a tropical depression by Tuesday afternoon.
Irma has a very large wind field. Hurricane-force winds extend
outward up to 60 miles (95 km) mainly to the west of the center, and
tropical-storm-force winds extend outward up to 415 miles (665 km).
The estimated minimum central pressure is 970 mb (28.64 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...
Cape Sable to Captiva...2 to 4 ft
Captiva to Anna Maria Island...3 to 5 ft
North Miami Beach to Cape Sable, including the Florida Keys...1 to 2
Anna Maria Island to Clearwater, including Tampa Bay...2 to 4 ft
South Santee River to Fernandina Beach...4 to 6 ft
Clearwater Beach to Ochlockonee River...4 t 6 ft
Fernandina Beach to Jupiter Inlet...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 are spreading into
southern Georgia. Tropical storm conditions should spread into the
eastern Florida Panhandle today. Tropical storm conditions are also
expected to spread northward across the remainder of the warning
areas through today.
Rainfall: Irma is expected to produce the following rain
accumulations through Wednesday:
The Florida Keys and southern Florida peninsula: additional 1 inch.
Central Florida peninsula: additional 1 to 3 inches.
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.
TORNADOES: A few tornadoes are possible across northeast Florida
and southeast portions of Georgia and South Carolina through
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 AM EDT.