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What is a Tornado Watch?

A Kaminsky
A Kaminsky

People moving into areas where tornadoes are common may hear the term "tornado watch" without knowing exactly what it means. A tornado watch means that weather conditions in and around the watch area are going to deteriorate and tornado activity is possible. The Storms Prediction Center in Norman, Oklahoma issues tornado watches. The center analyzes conditions in storm-prone areas and determines whether tornado activity is likely. A watch is then issued.

A tornado watch is defined in a rectangular area, sometimes covering hundreds of square miles. The tornado watch is usually of several hours' duration and is issued some time before severe weather is expected in the area. The advance issuance is designed to warn people that bad weather is approaching and give them time to review safety precautions and take action to keep themselves safe.

Storms and lightning often precede a tornado.
Storms and lightning often precede a tornado.

A tornado watch is not the same kind of advisory as a tornado warning. A warning is issued by the local National Weather Service office and means that a funnel cloud has either been sighted by a trained spotter or is indicated on radar. Tornado warnings are issued for specific areas of one county at a time. During a tornado warning, the emergency management agency of the county sounds tornado sirens in the affected areas.

People in tornado prone areas should have a NOAA weather radio that sounds an alarm if a tornado watch is issued.
People in tornado prone areas should have a NOAA weather radio that sounds an alarm if a tornado watch is issued.

Even if the sun is shining when a tornado watch is issued, a person should take the advisory very seriously. A tornado warning may never be issued, but it's a good bet that severe thunderstorms will move through the area, and these carry high winds, cloud-to-ground lightning and sometimes hail. Straight-line winds are also a risk with severe thunderstorms.

A basement or cellar can be used when seeking protection from a tornado.
A basement or cellar can be used when seeking protection from a tornado.

Those who live in tornado-prone areas usually have NOAA weather radios that sound an alarm when their county goes under a tornado watch or warning. These are especially important at night, since sirens may not be audible over high winds, but the alarm is sufficiently loud to wake even a sound sleeper. A tornado watch should always mandate action, even if it is just to monitor weather conditions. Doing so may save a life.

Frequently Asked Questions

What exactly is a tornado watch?

A tornado watch is an alert issued by the National Weather Service when weather conditions are favorable for the development of tornadoes in and close to the watch area. It doesn't mean a tornado has been spotted but indicates that you should be prepared and vigilant for potential severe weather, including the possibility of tornadoes forming.

How is a tornado watch different from a tornado warning?

A tornado watch suggests that tornadoes are possible, while a tornado warning, issued by the National Weather Service, means that a tornado has been sighted or indicated by weather radar. During a warning, immediate action is crucial as there is a direct threat to life and property in the path of the storm.

What should I do during a tornado watch?

During a tornado watch, stay informed by monitoring weather updates and have a plan in place. Identify a safe shelter, such as a basement or an interior room on the lowest floor of a sturdy building, and gather emergency supplies, including water, non-perishable food, a flashlight, and a first-aid kit. Stay ready to act if the watch escalates to a warning.

How long does a tornado watch typically last?

The duration of a tornado watch can vary, but they typically last for several hours. The National Weather Service will specify the time frame when issuing the watch. It's important to remain alert throughout the entire watch period, as conditions can change rapidly, potentially leading to a tornado warning.

Can a tornado watch be upgraded to a tornado warning?

Yes, a tornado watch can be upgraded to a tornado warning if tornadoes become imminent or are reported by spotters or indicated by radar. This upgrade signifies an immediate threat, and those in the affected area should seek shelter immediately and follow safety instructions from local authorities.

How often are tornado watches issued?

The frequency of tornado watches depends on geographic location and time of year. Tornado-prone areas, particularly in the central United States known as "Tornado Alley," may experience a higher number of watches during peak tornado season, which typically runs from early spring through summer, according to the National Oceanic and Atmospheric Administration.

Discussion Comments


@CarrotIsland: While they, thankfully, did not cause as many deaths as the 1925 tornadoes, the storms that hit Alabama on April 27, 2011 were the same kind of severe, long-track tornadoes that stayed on the ground for several hours and over 100 miles, with wind speeds estimated at 218 mph. Two EF-5 tornadoes formed that day, with four EF-4 storms, seven EF-2 tornadoes, 22 EF-1 storms and five EF-0 tornadoes, for a total of 40 storm tracks, and 62 tornadoes statewide. The Huntsville National Weather Service site has a wealth of information about the storms that day. They issued over 90 tornado warnings in their coverage area in about a 14-hour period. We were without power for four days and are just thankful to be here! We take tornado watches seriously around here!


@stormyknight: What made this tornado so tragic is that there was no warning systems back then. Also, in those days, the US Weather Bureau was not allowed to use the word “tornado” because they didn’t want to cause a panic. The people didn’t even realize a tornado was coming until it was right in their face.


@stormyknight: The worst tornado ever recorded was on March 18th, 1925. It is known as the Great Tri-State Tornado. It spun across Missouri, Indiana, and Illinois after 3 ½ hours of destruction. The tornado traveled at a speed of greater than 60 mph with wind speeds, incredibly, between 261 and 318 mph. This tornado was rated an F5.

During this tragic weather event, 652 deaths were reported with an additional 2000+ people injured. The tornado traveled 219 miles which is the longest distance recorded in history. 15,000 homes were destroyed. Property damage was estimated at $16.5 million dollars, which would be around $2 billion today.


What was the worst tornado that has hit the U.S.?


How do you tornado watch?

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    • Storms and lightning often precede a tornado.
      By: Leonid
      Storms and lightning often precede a tornado.
    • People in tornado prone areas should have a NOAA weather radio that sounds an alarm if a tornado watch is issued.
      By: Minerva Studio
      People in tornado prone areas should have a NOAA weather radio that sounds an alarm if a tornado watch is issued.
    • A basement or cellar can be used when seeking protection from a tornado.
      By: Steven Baines
      A basement or cellar can be used when seeking protection from a tornado.