Severe summer storms can cause damaging winds, hail, rural fires, flash flooding, and power outages. A well-informed and prepared public can better cope with and survive life threatening severe summer storms. http://www.weather.gov/bis/
A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still uncertain. It is intended to provide enough lead time so that those who need to set their plans in motion can do so.
A warning is issued when a hazardous weather or hydrologic event is occurring, is imminent, or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property.