Helene has been upgraded to a hurricane as of the 11am Advisory. Essentially all of Florida, Georgia, and southern South Carolina are under tropical storm warnings as expected., and the big bend of Florida and southwest Georgia hurricane warnings.
Some of the models show a much stronger storm at landfall - a few even a Cat 5 - but some are also not as strong as NHC is forecasting for a variety of reasons. That said, preparing for at least strong category 3 storm in the warned areas makes good sense. if you are on the Gulf coast of Florida and advised to evacuate, don't gamble your life on a forecast, get out! For those of us in the lowcountry and coastal empire we are still under a hurricane warning even though the storm's path has shifted more to the west.
NHC has again expanded the forecast wind field showing Helene as a medium strength tropical storm as it marches through Atlanta and may cause roof damage and trees down all the way to Chattanooga! The current track and intensity also includes parts of Alabama in the potential damage swath.
This storm is not like Debby. It a quick mover and not a big river flooding threat. Wind will be the primary focus.
Rain-wise, many areas in the Coastal Empire and Lowcountry will receive 2-4+” with locally higher amounts possible.
Hurricane Helene Advisory Number 9
NWS National Hurricane Center Miami FL AL092024
1000 AM CDT Wed Sep 25 2024
...HELENE BECOMES A HURRICANE...
...EXPECTED TO BRING LIFE-THREATENING STORM SURGE, DAMAGING WINDS,
AND FLOODING RAINS TO A LARGE PORTION OF FLORIDA AND THE
SOUTHEASTERN UNITED STATES...
SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.6N 86.3W
ABOUT 85 MI...135 KM NNE OF COZUMEL MEXICO
ABOUT 500 MI...810 KM SSW OF TAMPA FLORIDA
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...979 MB...28.91 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
The Tropical Storm Warning has been extended northward along the
coasts of Georgia and South Carolina to South Santee River, and
westward along the Florida Gulf coast to the Okaloosa/Walton County
Line.
A Storm Surge Watch has been issued from Mexico Beach to Indian
Pass, Florida.
A Tropical Storm Watch has been issued along the coast of South
Carolina north of South Santee River to Little River Inlet.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* Indian Pass 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 Storm Surge Watch is in effect for...
* West of Indian Pass to Mexico Beach
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 South Santee River
* Lake Okeechobee
* Rio Lagartos to Cabo Catoche, Mexico
* Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth
A Tropical Storm Watch is in effect for...
* North of South Santee River to Little River Inlet
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.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area.
Additional watches or warnings may be required later today.
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 1000 AM CDT (1500 UTC), the center of Hurricane Helene was
located near latitude 21.6 North, longitude 86.3 West. Helene is
moving toward the north-northwest near 10 mph (17 km/h). A turn
toward the north and north-northeast with an increase in forward
speed is expected later today through Thursday, bringing the center
of Helene across the eastern Gulf of Mexico and to the Florida Big
Bend coast by Thursday evening. After landfall, Helene is expected
to slow down and turn toward the northwest over the southeastern
United States Friday and Saturday.
Data from NOAA and Air Force Reserve Hurricane Hunter aircraft
indicate that maximum sustained winds have increased to near 80 mph
(130 km/h) with higher gusts. Additional 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 275 miles
(445 km).
The minimum central pressure based on dropsonde is 979 mb (28.91
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 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 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 Chassahowitzka, FL...10-15 ft
Chassahowitzka, FL to Anclote River, FL...6-10 ft
Indian Pass, FL to Carrabelle, 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
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 2 to 4 feet above
ground level in areas of onshore winds within the warning area along
the east 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 later today and will spread northward
across the rest of Florida, Georgia, and South Carolina through
Thursday. Tropical storm conditions are possible within the
tropical storm watch area in South Carolina beginning on Thursday.
Hurricane conditions, especially in gusts, are expected in the
hurricane warning area in Mexico during the next several hours.
Tropical storm conditions are occurring in the warning area in Cuba,
and hurricane conditions are possible for the western portion of
Cuba today.
RAINFALL: 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 the Southeastern U.S. into the Southern Appalachians, Helene
is expected to produce total rain accumulations of 5 to 10 inches
with isolated totals around 15 inches. This rainfall will likely
result in areas of considerable flash and urban flooding, with areas
of significant river flooding. Landslides are possible in areas of
steep terrain in the southern Appalachians.
For a complete depiction of forecast rainfall associated with
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 later today and Thursday. These
swells are likely to cause life-threatening surf and rip current
conditions. Please consult products from your local weather office.