742
WTNT34 KNHC 252344
TCPAT4

BULLETIN
Hurricane Helene Intermediate Advisory Number 10A
NWS National Hurricane Center Miami FL       AL092024
700 PM CDT Wed Sep 25 2024

...HELENE LIKELY TO BECOME A MAJOR HURRICANE TOMORROW...
...PREPARATIONS TO PROTECT LIFE AND PROPERTY ALONG THE FLORIDA BIG
BEND COAST SHOULD BE RUSHED TO COMPLETION...

SUMMARY OF 700 PM CDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...23.0N 86.6W
ABOUT 430 MI...690 KM SW OF TAMPA FLORIDA
ABOUT 475 MI...760 KM SSW OF APALACHICOLA FLORIDA
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...974 MB...28.76 INCHES

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* Mexico Beach eastward and southward to Flamingo
* Tampa Bay
* Charlotte Harbor

A Hurricane Warning is in effect for...
* Anclote River to Mexico Beach
* Cabo Catoche to Tulum, Mexico including Cozumel

A Hurricane Watch is in effect for...
* Cuban province of Pinar del Rio
* Englewood to Anclote River, including Tampa Bay

A Tropical Storm Warning is in effect for...
* Florida Keys, including the Dry Tortugas
* Flamingo to Anclote River, including Tampa Bay
* West of Mexico Beach to the Okaloosa/Walton County Line
* Flamingo northward to Little River Inlet
* Lake Okeechobee
* Rio Lagartos to Cabo Catoche, Mexico
* Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth

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.

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.  A warning is typically issued
36 hours before the anticipated first occurrence of
tropical-storm-force winds, conditions that make outside
preparations difficult or dangerous.  Preparations to protect life
and property should be rushed to completion.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within the next 36 hours.

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.

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
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.

DISCUSSION AND OUTLOOK
----------------------
At 700 PM CDT (0000 UTC), the center of Hurricane Helene was located
near latitude 23.0 North, longitude 86.6 West.  Helene is moving
toward the north near 12 mph (19 km/h).  A northward or
north-northeastward motion at a faster forward speed is expected
during the next 36 hours.  On the forecast track, Helene will move
across the eastern Gulf of Mexico tonight and Thursday and cross the
Florida Big Bend coast Thursday evening.  After landfall, Helene is
expected to turn northwestward and slow down over the Tennessee
Valley on Friday and Saturday.

Maximum sustained winds are near 85 mph (140 km/h) with higher
gusts.  Strengthening is forecast, and Helene is expected to be a
major hurricane when it reaches the Florida Big Bend coast Thursday
evening.  Weakening is expected after landfall, but Helene's fast
forward speed will allow strong, damaging winds, especially in
gusts, to penetrate well inland across the southeastern United
States, including over the higher terrain of the southern Appalachians.

Hurricane-force winds extend outward up to 25 miles (35 km) from
the center and tropical-storm-force winds extend outward up to 345
miles (555 km).

The minimum central pressure estimated from Hurricane Hunter
aircraft observations is 974 mb (28.76 inches).

HAZARDS AFFECTING LAND
----------------------
Key Messages for Helene can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC
and on the web at hurricanes.gov/text/MIATCDAT4.shtml

STORM SURGE: The combination of a life-threatening 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...

Carrabelle, FL to Suwannee River, FL...15-20 ft
Apalachicola, FL to Carrabelle, FL...10-15 ft
Suwannee River, FL to Chassahowitzka, FL...10-15 ft
Chassahowitzka, FL to Anclote River, FL...8-12 ft
Indian Pass, FL to Apalachicola, FL...6-10 ft
Anclote River, FL to Middle of Longboat Key, FL...5-8 ft
Tampa Bay...5-8 ft
Middle of Longboat Key, FL to Englewood, FL...4-7 ft
East of Mexico Beach, FL to Indian Pass, FL...3-5 ft
Englewood, FL to Flamingo, FL...3-5 ft
Charlotte Harbor...3-5 ft

For a complete depiction of areas at risk of storm surge inundation,
please see the National Weather Service Peak Storm Surge Graphic,
available at hurricanes.gov/graphics_at4.shtml?peakSurge.

Storm surge could raise water levels by as much as 2 to 4 feet above
normal tide levels in areas of onshore winds along the southern
coast of Pinar del Rio, Cuba, including the Isle of Youth.

Storm surge could raise water levels by as much as 3 to 5 feet above
ground level in areas of onshore winds within the warning area along
the north coast of the Yucatan Peninsula.

WIND: Hurricane conditions are expected within the U.S. hurricane
warning area late Thursday, with tropical storm conditions
beginning Thursday morning.  Tropical storm conditions are expected
in southern Florida tonight and will spread northward across the
rest of Florida, Georgia, and South Carolina through Thursday night.

Hurricane conditions, especially in gusts, are expected in the
hurricane warning area in Mexico during the next few hours.
Tropical storm conditions are occurring in the warning area in Cuba,
and hurricane conditions are possible for the western portion of
Cuba this evening.

RAINFALL: Hurricane Helene is expected to produce total rain
accumulations of 4 to 8 inches over western Cuba, the Cayman Islands
and the northeast Yucatan Peninsula, with isolated totals around 12
inches. This rainfall brings a risk of considerable flooding.

Over portions of the southeastern U.S. into the southern
Appalachians, Helene is expected to produce total rain accumulations
of 6 to 12 inches with isolated totals around 18 inches. This
rainfall will likely result in catastrophic and potentially
life-threatening flash and urban flooding, along with significant
river flooding.  Landslides are possible in steep terrain across the
southern Appalachians.

For a complete depiction of forecast rainfall associated with
Hurricane Helene, please see the National Weather Service Storm
Total Rainfall Graphic, available at
hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk
graphic at hurricanes.gov/graphics_at4.shtml?ero.

TORNADOES: A tornado or two may occur tonight over parts of the
Florida Peninsula and southern Alabama.  The risk of tornadoes will
increase on Thursday, expanding northward across Florida into parts
of Georgia and South Carolina.

SURF: Swells generated by Helene will affect the southern coast of
Cuba and the Yucatan Peninsula of Mexico during the next couple of
days.  Swells will spread northward toward the west coast of Florida
and the northeastern Gulf Coast tonight and Thursday. These swells
are likely to cause life-threatening surf and rip current
conditions.  Please consult products from your local weather office.

NEXT ADVISORY
-------------
Next complete advisory at 1000 PM CDT.

$$
Forecaster Pasch
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