Severe Weather Glossary

Advisory – An advisory highlights special weather conditions that are less serious than a warning. They are for events that may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property. Examples are wind advisories and small craft advisories.

Watch – A watch is used when there is the risk of severe weather. It is intended to provide enough lead time so that those who need to set their plans in motion can do so.

Warning - A warning is issued when severe weather is occurring or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property.

WATCHES

Flood Watch – Issued to inform the public that there is a threat of flooding, but the occurrence is neither certain nor imminent.

Severe Thunderstorm Watch – Issued when conditions are favorable for the development of severe thunderstorms in and close to the watch area. A severe thunderstorm by definition is a thunderstorm that produces hail at least ¾”, and/or winds at least 58 miles an hour. They are usually issued for a duration of 4 to 8 hours and are issued well in advance of the actual occurrence of severe weather.

Tornado Watch – Issued when conditions are favorable for the development of tornadoes in and close to the watch area. They are usually issued for a duration of 4 to 8 hours and are issued well in advance of the actual occurrence of severe weather.

WARNINGS

Flood Warning – Issued to inform the public that flooding is imminent or in progress.

Severe Thunderstorm Warning – Issued when either a severe thunderstorm is indicated by radar or a spotter reports a thunderstorm producing at least ¾” hail, and/or winds at least 58 miles an hour. Severe thunderstorms can also produce tornadoes with little or no advance warning. They are usually issued for a duration of one hour.

Tornado Warning – Issued when a tornado is indicated by radar. They are usually issued for a duration of around 30 minutes.