UPDATE: Expect quarter-sized hail with thunderstorms to hit North Texas Saturday

The National Weather Service issued an updated severe thunderstorm warning at 12:34 p.m. on Saturday in effect until 1 p.m. The warning is for Dallas, Denton and Tarrant counties.

The storms are expected to bring quarter-sized hail (1 inch).

"At 12:34 p.m., a severe thunderstorm was located over Grapevine, moving east at 35 mph," says the NWS. "Damage to vehicles is possible."

Locations impacted by the warning include Dallas, Plano, Irving, Carrollton, Lewisville, Flower Mound, Euless, Bedford, Grapevine, Keller, Coppell, Hurst, The Colony, Farmers Branch, Southlake, Colleyville, Highland Village, Addison, Trophy Club and North Richland Hills.

According to the NWS, "For your protection stay inside a sturdy structure and keep away from windows."

This warning is in effect until 1 p.m.

What to do as threat of lightning approaches?

Lightning strikes the United States about 25 million times a year. Most of the strikes occur in the summer, killing 20 people each year, according to the NWS. Chance of lightning increases as a thunderstorm approaches and peaks when the storm is overhead. It diminishes as the storm moves away.

Here are suggestions for staying safe during a thunderstorm:

• To minimize risk of being struck by lightning, when going outside, have a plan to get to a safer place.

• If the sky turns ominous and thunder can be heard, find a secure place for shelter.

• Once indoors, avoid touching corded phones, electrical equipment, plumbing, and windows and doors.

• Wait for 30 minutes after the final lightning or thunder before heading outside again.

If finding indoor shelter is not an option:

• Avoid open fields, hill peaks, or ridge tops.

• Avoid tall, isolated trees or other elevated objects. If you are in a forest, stick to areas with shorter tree cover.

• If you are in a group, disperse to prevent the current from passing between group members.

• If you are camping in an open area, set up camp in a valley, ravine, or other low area. Remember, a tent offers no protection from lighting.

• Keep a distance from water, wet articles, and metal objects. While water and metal do not draw lightning, they are proficient conductors of electricity.

What to do in the rain on the road?

• Turn on your headlights — Even when it's light outside, using headlights can improve visibility and alert other drivers to your presence.

• While driving — Stick to the middle lanes and stay on elevated ground. Rainwater tends to accumulate at the road edges.

• Avoid puddles — Driving into puddles or low rainwater areas can lead to vehicles hydroplaning or losing control.

• Give ample space to large vehicles — Trucks or buses can create a water spray that diminishes visibility.

• Steer clear of flooded areas — When coming to a flooded road, turn around and head back. Flash flooding currents are strong and can sweep drivers off roadways. Driving through deep water can also affect a vehicle’s mechanical and electrical systems.

What is hydroplaning?

Hydroplaning is the term for when a vehicle begins sliding uncontrollably on wet roads.

This happens when water in front of the tire builds up faster than the vehicle’s weight can push water out of the way. The water pressure then causes the vehicle to rise and slide on a thin layer of water between the tires and the road, making the driver lose control. The top three contributors to hydroplaning are:

1. Vehicle speed — When a vehicle’s speed increases, the tire-traction grip and ability to control the vehicle decreases. Drive at a reduced speed during wet weather.

2. Water depth — The deeper the water, the sooner a vehicle loses traction on the road. It doesn’t matter how deep the water is, even a thin layer can lead to hydroplaning.

3. Tire tread depth — Checking your tire tread before hitting the road is important, as low or no tread can lead to sliding.

In the event of your vehicle hydroplaning, here’s what to know:

• Ease off the accelerator — Step off the gas to slow down the vehicle until the tires find traction.

• Turn into the skid — Turning into the skid can help the vehicle’s tires realign to regain control.

• Make sure the tires reconnect with the road — During the skid, wait until the tires reconnect with the road and then gently straighten the wheels to regain control.

• Brake gently as needed — Brake normally if the vehicle has anti-lock brakes and pump brakes gently if in an older vehicle.

Source: The National Weather Service