A thunderstorm is a type of storm that generates lightning and the attendant thunder. It is normally accompanied by heavy precipitation. These storms occur when high levels of condensation form in a volume of unstable air that generates deep, rapid, upward motion in the atmosphere. The heat energy creates powerful rising air currents that swirl upwards to the tropopause. Cool descending air currents produce strong downdraughts below the storm.
Thunder is the sound made by lightning. Depending on the nature of the lightning and distance of the listener, thunder can range from a sharp, loud crack to a long, low rumble (brontide). The sudden increase in pressure and temperature from lightning produces rapid expansion of the air surrounding and within a bolt of lightning. In turn, this expansion of air creates a sonic shock wave which produces the sound of thunder, often referred to as a clap, crack, or peal of thunder.
The attraction, or electrical potential, between the positive and negative charges eventually grows strong enough to overcome the air's resistance to electrical flow. Racing toward each other, the charges connect, completing an electrical circuit, and discharging the accumulated electricity as lightning. Cloud-to-cloud lightning is the most common form of electrical discharge. Only about one-third of all discharges are cloud-to-ground.
Severe Thunderstorm Watch is issued when severe thunderstorms are possible in and close to the watch area. The watch is issued to alert you to the possibility that thunderstorms with damaging winds and large hail may develop. Listen to NOAA Weather Radio and your local media weather updates and stay informed!
Severe Thunderstorm Warning is issued when a severe thunderstorm has been spotted and is going to move through your county soon. The key is to remain calm, but take precautionary action immediately to protect your life and property.