National Weather Service United States Department of Commerce

Important Definitions


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):

SPC Categories - Click to enlarge

Severe Thunderstorm/Tornado Safety Basics:

1. Get In:

  • Put as many walls between you and the outside as possible.
  • Stay Away from doors and windows.

2. Get Down:

  • Get to the lowest floor possible. Basements are best during tornadic or very high wind situations.

3. Cover Up

4. Remain Calm

More details can be found within this brochure: pdf version  


Types of Severe Weather:


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


Be Prepared with NOAA All Hazards Radio

  • Your single source for comprehensive weather and emergency information!

More Information:


Vulnerable Population Resources

Safety - Deaf and Hard of Hearing
Safety - Intellectual Disabilities
Seguridad Meteorológica (Español)
Sobre Embajadores Weather-Ready Nation (Español)

(If the links below do not work, please visit the NWS Publications Page)


Thunderstorms, Lightning, and Tornadoes - Natures Most Violent Storms
Enhanced Fujita Tornado Intensity Scale

Thunderstorms and Lightning

Thunderstorms, Lightning, and Tornadoes - Natures Most Violent Storms
NOAA Lightning Safety Page
Storm Spotter's Field Guide

Flooding/Flash Flooding

Flash Floods and Floods - The Awesome Power (15MB pdf)

Winter Weather

Winter Storms, The Deceptive Killers (large PDF)

Hurricanes and Tropical Storms

Hurricane Safety  (PDF)
Saffir/Simpson Hurricane Scale
Hurricane Names
National Hurricane Center

Summer Heat

All About Heat Waves
Heat Index Chart

DroughtDrought Information Center