Watch: Issued when conditions are favorable for a particular severe weather hazard within the next several hours.
Warning: Issued when a particular severe weather hazard is imminent or occurring. Take immediate action to protect life and property.
Storm Prediction Center Outlook Categories (click to enlarge):
1. Get In:
2. Get Down:
3. Cover Up
4. Remain Calm
More details can be found within this brochure: pdf version
Tornado: A violently rotating column of air extending from a thunderstorm cloud to the ground. The Enhanced Fujita Tornado Intensity Scale is used to categorize tornadoes.
Severe Thunderstorm: A thunderstorm that produces a tornado, damaging winds of 58 mph or higher, and/or quarter (1 inch) size hail or larger.
Flash Flood: a flood which will create an immediate threat to life or property. Safety rules for flash flooding can be found with this brochure (15MB pdf)
High Wind: A High Wind Warning is issued for sustained winds of 40 mph or wind gusts of 58 mph
Thunderstorms and Lightning
Flash Floods and Floods - The Awesome Power (15MB pdf)
Winter Storms, The Deceptive Killers (large PDF)
Hurricanes and Tropical Storms