🌪️ Tornado Simulator

Tornado Warning vs. Watch

A tornado watch means conditions are favorable for tornadoes. A tornado warning means a tornado has been sighted or detected on radar — take shelter immediately. That single difference — "get ready" versus "act now" — has saved and cost thousands of lives.

How to Remember the Difference

The classic memory device: Watch = the ingredients are in the bowl. Warning = the cake is in the oven. A watch means the atmosphere has the ingredients to make tornadoes. A warning means a tornado is actually forming or has already formed.

Who Issues What

• Tornado Watches are issued by the NOAA Storm Prediction Center (SPC) in Norman, Oklahoma. SPC forecasters monitor the national atmospheric picture and issue watches when a multi-hour severe weather episode is expected.
• Tornado Warnings are issued by your local National Weather Service (NWS) forecast office — there are 122 in the US. Local forecasters watch radar in real time and issue warnings when they see a tornado signature or receive a spotter report.

Higher Levels of Warning

Particularly Dangerous Situation (PDS) Watch

An enhanced tornado watch issued when the SPC believes violent (EF3+) or long-track tornadoes are likely. Treat a PDS watch as extremely serious — historically, PDS watches precede outbreaks that produce EF4/EF5 tornadoes.

Tornado Emergency HIGHEST

The highest level of NWS tornado warning. Issued when a confirmed strong tornado is bearing down on a populated area. The wording typically includes phrases like "catastrophic damage expected" or "this is a life-threatening situation." Recent examples: Joplin 2011, Moore 2013, Rolling Fork 2023, Mayfield 2021.

If your area is under a Tornado Emergency, this is the most urgent shelter directive the NWS can issue. Do not wait for confirmation. Move to your safest shelter now.

Severe Thunderstorm Watch/Warning

Not the same as tornado alerts, but closely related:

• Severe Thunderstorm Watch — conditions favor thunderstorms with 58+ mph winds, 1"+ hail, or both.
• Severe Thunderstorm Warning — a severe storm has been detected. Tornadoes can occur in severe thunderstorms even without a tornado warning — always take severe storm warnings seriously.

How You Receive Warnings

• NOAA Weather Radio — a dedicated radio that alerts on watches/warnings even if you're asleep or the power is out. Around $30–50 for a good model. Essential in tornado-prone areas.
• Wireless Emergency Alerts (WEA) — automatic phone notifications sent to any phone in the warning polygon. Verify your phone has them enabled.
• Outdoor sirens — designed to warn people outdoors, not indoors. Not reliable if you're inside a home.
• Weather apps (RadarScope, MyRadar, etc.) — good for real-time tracking but require power and cell service, both of which may fail during severe weather.
• Local TV/radio — good backup if you're already indoors.

Warning Lead Time

The average NWS tornado warning lead time has grown from roughly 8 minutes in 1990 to about 13 minutes today. Some individual warnings have lead times of 30+ minutes; others (fast-moving or rapidly-forming tornadoes) can be issued with under 5 minutes' notice.

False alarm rates remain a challenge: roughly 70% of NWS tornado warnings result in no confirmed tornado. This is the driver of "warning fatigue" — people stop taking warnings seriously after repeated false alarms. The NWS has been working to reduce false alarm rates without reducing lead time, but the physics of tornado detection makes both goals hard to achieve simultaneously.

→ Simulate a tornado warning scenario