🌪️ Tornado Simulator

Tornado Warning vs Severe Thunderstorm Warning

A Tornado Warning and a Severe Thunderstorm Warning are both issued by the NWS but respond to different threats. Understanding the difference matters because your response should be different. Here's the definitive comparison.

Tornado Warning

What It Means

A tornado is detected or imminent in your area.

Criteria

• Radar shows tornado vortex signature
• Storm spotter reports tornado
• Confirmed tornado on ground
• Rotation strong enough to warrant warning

Required Response

• Immediate shelter
• Interior room, lowest floor
• Away from windows
• Cover head
• Stay put until all-clear

Severe Thunderstorm Warning

What It Means

A thunderstorm producing damaging conditions is in your area.

Criteria

Storm must produce ANY of:

• Winds ≥58 mph
• Hail ≥1 inch diameter
• Or tornado activity (upgrades to tornado warning)

Required Response

• Move inside
• Away from windows
• Avoid lightning exposure
• Watch for possible tornado formation
• Interior room if severe

Key Differences

Threat Level

• Tornado warning: Highest immediate threat
• Severe thunderstorm: Serious but not tornado-level

Response Urgency

• Tornado warning: Immediate shelter required
• Severe thunderstorm: Take shelter but less urgent

Path Predictability

• Tornado warning: Difficult to predict exact path
• Severe thunderstorm: Broader area affected, more predictable

Damage Type

• Tornado warning: Rotational damage, targeted
• Severe thunderstorm: Straight-line wind, hail damage

Why Both Matter

Severe Thunderstorm Can Produce Tornadoes

Any severe thunderstorm can develop tornado potential:

• Monitor upgrade to tornado warning
• Watch for signs of rotation
• Take shelter earlier
• Both warrant caution

Straight-Line Winds Are Dangerous

Severe thunderstorm winds cause:

• Downed trees
• Roof damage
• Power outages
• Vehicle damage
• Similar damage to weak tornadoes

Hail is Dangerous

Large hail:

• Injuries possible
• Vehicle damage
• Roof damage
• Broken windows
• Wildlife/livestock impact

Real-World Comparison

2020 Nashville Event

Multiple upgrades from severe thunderstorm to tornado warning during outbreak.

2011 Joplin

Severe thunderstorm warning preceded, then upgraded to tornado warning.

Multiple Historical Events

Tornado warnings often upgrade from severe thunderstorm warnings as storms develop.

The Warning Process

Storm Development

Warnings evolve:

1. Storm develops
2. Severe thunderstorm warning issued
3. Storm intensifies
4. Rotation detected
5. Tornado warning issued (may replace severe)
6. Both may be active simultaneously in area

Warning Boundaries

Warnings can be:

• Adjacent (different areas)
• Overlapping (same area, different threats)
• Progressive (updates as storm evolves)
• Multi-county coverage

Communication

NOAA Weather Radio

Both alert types trigger:

• Attention tone
• Voice announcement
• Emergency alerts
• Continuous coverage during severe weather

Wireless Emergency Alerts (WEA)

Different alert priorities:

• Tornado warnings: highest priority
• Severe thunderstorm warnings: lower priority in some areas
• Configurable in phone settings

Local Media

Both types interrupted broadcasting:

• Tornado warnings: extended coverage
• Severe thunderstorms: brief interruption
• Live meteorologist coverage during severe events

When Both Are Issued

Multiple Warnings Active

You may have both warnings active:

• Overlapping polygons
• Multiple threat types
• Both require action
• Highest threat (tornado) takes priority

Response

When both are active:

• Follow tornado warning protocols
• Take shelter immediately
• Prepare for straight-line winds also
• Prepare for hail also

Seasonal Considerations

Spring/Summer

Peak season for both types of warnings.

Multi-Hazard Days

Some days produce multiple severe weather threats.

Regional Variation

Different regions see different mix of warnings.

Bottom Line

A Tornado Warning means immediate shelter needed from confirmed tornado. A Severe Thunderstorm Warning means damaging winds or hail from strong thunderstorm. Both warrant caution and interior room shelter, but tornado warnings require faster and more decisive action. When in doubt, treat any severe weather warning like it could become a tornado warning - and take shelter accordingly.

→ Simulate a tornado on our map