SAVANNAH, Ga. (WTOC) - Severe Thunderstorm Warnings are common, especially in the spring and summer across the Lowcounty and Coastal Empire, but have you ever wondered why some storms are warned and others aren’t?
First of all, the WTOC viewing area is monitored by the National Weather Service in Charleston, South Carolina and Jacksonville, Florida.
All Watches, Warnings and Advisories are issued by the National Weather Service based on a specific criteria.
A Severe Thunderstorm Warning can be issued for three reasons:
1) Hail at least 1″ in diameter, wind of 58 miles per hour or greater and tornadoes. NOT because of lightning!
Hail: Hailstones of at least 1″ in diameter can fall between 25 and 40 miles per hour.
Even though we don’t typically see very large hail here in the Lowcounty and Coastal Empire, hail can grow much larger than 1″ in diameter!
In fact, hailstones of 2-4″ in diameter can fall up to 72 miles per hour, but this is more typically seen in the in the central and northern plains.
Outside of the United States, hailstorms can happen in China, Russia, India and portions of Italy.
It comes as no surprise that hail can do significant damage to cars, roofs and crops.
If possible, get in side a building and away from windows to avoid getting hit by blowing glass!
Wind: Once wind in thunderstorms reach 58 miles per hour (50 knots) it is considered severe.
Straight-line wind is one of the most common forms of severe weather reports.
In fact, In the lower 48 United States, damaging wind accounts for half of our severe reports.
Most wind-related Severe Thunderstorm Warnings are for wind up to 60-70 miles per hour, but thunderstorms have produced wind greater than 100 miles per hour!
It is important to remember that strong straight-line wind can do just as much damage as weak tornadoes.
Tornadoes: Any thunderstorm producing a tornado is considered severe.
The United States experiences about 1,200 tornadoes a year.
These tornadoes range in strength from EF-0 (65 - 85 mph) up to EF-5 (200+ mph), most tornadoes range from EF-0 to EF-2.
Tornadoes can cause great destruction, flipping cars and wiping homes from their foundation.
Making sure you and your family have a severe weather safety plan at home, school and at work is important since tornadoes can happen at any time of the day.
Make sure your family has multiple ways to receive weather alerts.
The WTOC Weather App, NOAA weather radios and TV are all good to have nearby when severe weather is possible.
You can download the WTOC Weather app on your mobile device here.