Watch, warning, advisory: What do they mean?

By Josh Linker, Meteorologist
Last Updated: Wednesday, May 27, 2015, 4:47 PM EDT

We have had some storms this spring, even though spring is normally quiet for us. We have more stormy weather expected this week.

Of course, we have rough weather almost every day during our summer rainy season as well. To get the word out of the importance of a particular weather situation, titles are given. Advisory, Watch, and Warning are the ones that are most commonly used. But what do these mean?

A Watch is issued when there is a risk of hazardous weather in the relative short term but its exact location and timing is uncertain. A Severe Thunderstorm Watch, for example, will be issued for a larger area for several hours where and when conditions are favorable for severe thunderstorms. If you are under a watch like this, you need to be aware that at some point, the weather could become dangerous.

Layperson’s action: You need to WATCH the weather.

A Warning is issued when the hazardous or dangerous weather is occurring, is imminent, or is very likely to occur. A Severe Thunderstorm Warning, for example would be issued when a thunderstorm that meets the severe criteria (winds over 60 mph, hail larger than an inch in diameter) is happening right now. The warning area will be storm specific so it will be much smaller than the watch area.

Layperson’s action: You have been WARNED, the dangerous weather is occurring NOW, take necessary precautions to get out of harm’s way.

An Advisory is issued when certain weather is occurring but far less serious by itself that a warning. Think of an advisory of being issued for potentially significant inconvenience. But if you don’t use caution, then those situations may threaten life and or property.

In other words, the weather that leads to an advisory is only potentially dangerous if you act in a way that makes it dangerous. For example, a Flood Advisory is issued during some persistent heavy rains when there is the possibility of some street flooding, low lying areas, intersections, etc. That type of flooding woldn’t be dangerous unless you decided to try to drive through it. In the case of flooding, if the flooding is significant enough that a Flash Flood Warning or a Flood Warning could be issued.

You often hear us mention a strong thunderstorm in a particular location. This would be a thunderstorm strong enough to produce frequent lightning, small hail, gusty winds, and heavy rain. These would all fall under the “official” criteria for a severe thunderstorm, yet we feel you need to know about this storm. A heavy thunderstorm is the same, just not as intense as a strong or severe thunderstorm.

As always, stay with Bay News 9 and we’ll keep you advised.