UPDATED: Severe Thunderstorm WARNING: Cook, Lake and More Than a Dozen Counties

UPDATED: Friday, August 30 at 4:50 p.m.

The previous severe thunderstorm watch has now become a Severe Thunderstorm Warning. 

Severe thunderstorms are moving south at 35 miles per hour from Harvard. Half dollar sized hail is expected and 70 miles per hour wind gusts.

Hail is expected to damage vehicles, with considerable tree damage. Wind damage is also likely to mobile homes, rooftops and outbuildings.

Please be aware of the precautions below. The warning is in effect until 5:45 p.m. 

EARLIER:

A severe thunderstorm watch is in effect until 9:00 p.m. Friday night for the following Illinois counties, according to the National Weather Service: 

Cook, Lake, Boone, Bureau, Carroll, DeKalb, DuPage, Grundy, Jo Daviess, Kane, Kendall, La Salle, Lee, McHenry, Ogle, Putnam, Stephenson, Whiteside, Will and Winnebago.

Many area high school football and other sports are kicking off their seasons this afternoon and evening, and precautions can be taken. 

According to Ready.gov:

• To begin preparing, you should build an emergency kit and make a family communications plan.
• Remember the 30/30 Lightning Safety Rule: Go indoors if, after seeing lightning, you cannot count to 30 before hearing thunder. Stay indoors for 30 minutes after hearing the last clap of thunder.
• Secure outdoor objects that could blow away or cause damage.
• Get inside a home, building, or hard top automobile (not a convertible). Although you may be injured if lightning strikes your car, you are much safer inside a vehicle than outside.
• Shutter windows and secure outside doors. If shutters are not available, close window blinds, shades or curtains.
• More about what to do before thunderstorm and lightning.

• Avoid contact with corded phones and devices including those plugged into electric for recharging. Cordless and wireless phones not connected to wall outlets are OK to use.
• Avoid contact with electrical equipment or cords. Unplug appliances and other electrical items such as computers and turn off air conditioners. Power surges from lightning can cause serious damage.
• Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry. Plumbing and bathroom fixtures can conduct electricity.
• Stay away from windows and doors, and stay off porches.
• If you are driving, try to safely exit the roadway and park. Stay in the vehicle and turn on the emergency flashers until the heavy rain ends. Avoid touching metal or other surfaces that conduct electricity in and outside the vehicle.