Weather alerts use specific, standardized terminology to communicate the urgency and risk associated with severe weather events. Understanding the difference between a “Watch” and a “Warning” is foundational for public safety. These designations represent two distinct levels of threat that require different responses to protect life and property. The National Weather Service (NWS) issues these alerts to ensure the public knows when to prepare and when to act immediately.
Understanding the Alert Level: The Watch
A Watch designation means that conditions are favorable for a severe weather event to develop in or near a specified area. This alert communicates that the risk has increased significantly, but the severe weather is not yet occurring or certain to happen. For example, a severe thunderstorm Watch is issued when the atmospheric ingredients are present for damaging winds or large hail to form.
This alert covers a relatively large geographical area that may span numerous counties or even multiple states. Watches are typically issued well in advance of the potential event, often hours ahead, such as a hurricane Watch issued up to 48 hours before the possible onset of tropical storm-force winds. The purpose is to provide the public with enough lead time to prepare.
Understanding the Alert Level: The Warning
In contrast, a Warning means that a severe weather event is imminent, occurring now, or highly probable based on visual confirmation or radar detection. This designation indicates that danger is present and poses a direct threat to life and property. For instance, a tornado Warning is issued only when a tornado has been sighted by trained spotters or indicated by Doppler radar.
Warnings cover a much smaller, more localized area, often limited to a single city or small county. These alerts are issued for a very short timeframe, sometimes only 30 to 60 minutes, reflecting the immediacy of the threat. A Warning is an urgent call for action because the hazard is already developed and poses an immediate danger.
Immediate Action Required for Each Designation
The most practical difference between the two alerts lies in the required public response: a Watch demands preparation, while a Warning demands immediate protective action.
Watch Preparation
When a Watch is issued, individuals should take time to complete preparations. They should monitor local media and official weather channels for updated information. Preparations include:
- Gathering supplies, such as ensuring communication devices are fully charged and checking batteries in flashlights and NOAA weather radios.
- Identifying and securing safe places, such as an interior room on the lowest floor away from windows, or a designated community shelter.
- Securing loose outdoor items, like patio furniture or garbage cans, which could become dangerous projectiles in high winds.
Warning Action
When a Warning is issued, all preparatory actions must cease, and the response must shift immediately to protective measures. This means moving without delay to the pre-identified safe room or shelter, such as a basement, storm cellar, or an interior room away from exterior walls and windows. The immediate action involves taking cover and protecting the head and body from falling debris. For a tornado Warning, this means getting under a sturdy object or covering oneself with blankets or a mattress for additional protection.