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Hurricane Irma Discussion Number  43...Corrected
NWS National Hurricane Center Miami FL       AL112017
500 PM EDT Sat Sep 09 2017

Corrected day of week to Sunday in first Key Message

Data from a NOAA Hurricane Hunter plane sampling Irma indicate
that the hurricane has not recovered yet from its interaction
with Cuba. It is estimated that the maximum winds are 110 kt. Given
the excellent satellite presentation, the lower pressure just
reported by the NOAA plane, and the fact that the hurricane will
move over the warm waters of the Straits of Florida, some
intensification is anticipated during the next 24 hours. Irma is
expected to remain a very dangerous hurricane while it moves near or
over the Florida Keys and near or over the Florida Peninsula. After
48 hours, Irma will be moving farther inland and weakening.

Radar data indicate that Irma is moving toward the west-northwest
at about 8 kt. The turn toward the northwest and north-northwest is
about to begin since the hurricane is already at the western edge of
the subtropical ridge.  The track guidance continues to be tightly
packed, and the bulk of the models take the hurricane over the
Florida Keys and near or over the Florida Peninsula. The NHC
forecast is in the middle of the guidance envelope, and given the
good agreement among models, the confidence in the track forecast is
high.

KEY MESSAGES:

1. Irma is expected bring life-threatening wind and storm surge to
the Florida Keys and southwestern Florida as an extremely dangerous
major hurricane tonight through Sunday. Preparations in southwest
Florida should be completed within the next few hours, as
tropical-storm-force winds are expected to begin tonight.

2. There is an imminent danger of life-threatening storm surge
flooding in portions of central and southern Florida, including the
Florida Keys, where a Storm Surge Warning is in effect. The threat
of catastrophic storm surge flooding is highest along the southwest
coast of Florida, where 10 to 15 feet of inundation above ground
level is expected. This is a life-threatening situation, and
everyone in these areas should immediately follow any evacuation
instructions from local officials.

3. Irma will bring life-threatening wind impacts to much of Florida
regardless of the exact track of the center. Wind hazards from Irma
are also expected to spread northward through much of Georgia
and portions of South Carolina and Alabama.

4. Irma is expected to produce very heavy rain and inland flooding.
Total rain accumulations of 10 to 20 inches, with isolated amounts
of between 20 and 25 inches, are expected over the Florida Keys, the
Florida peninsula, and southeast Georgia from Saturday through
Monday. Significant river flooding is possible in these areas. Early
next week Irma will also bring periods of heavy rain to much of the
southeast United States where an average of 2 to 6 inches is
forecast, with isolated higher amounts, from North and South
Carolina to Tennessee and eastern Alabama. This includes some
mountainous areas which are more prone to flash flooding.  Residents
throughout the southeast states should remain aware of the flood
threat and stay tuned to forecasts and warnings.

FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 23.4N  80.5W  110 KT 125 MPH
 12H  10/0600Z 24.1N  81.3W  115 KT 130 MPH
 24H  10/1800Z 25.7N  82.0W  120 KT 140 MPH
 36H  11/0600Z 28.3N  82.6W  100 KT 115 MPH
 48H  11/1800Z 31.2N  83.8W   65 KT  75 MPH...INLAND
 72H  12/1800Z 35.5N  88.0W   25 KT  30 MPH...POST-TROP/INLAND
 96H  13/1800Z 36.1N  89.0W   25 KT  30 MPH...POST-TROP/INLAND
120H  14/1800Z...DISSIPATED

$$
Forecaster Avila/Brennan

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