Day two of Severe Weather Preparedness Week brings us to discussing Severe Thunderstorm Warnings and Watches. Similar to Tornado Warnings/Watches, it comes down to “when to take action” and “when to prepare to take action”. Here is an explanation of what each means and what you should do when one is issued.
First, there is a criteria used to define a thunderstorm “severe.” The National Weather Service defines a severe thunderstorm that is producing hail at least 1 inch in diameter or larger, and/or wind gusts 58 mph or greater, and/or a tornado.
A Severe Thunderstorm Warning is issued by your local National Weather Service office and is typically in effect for 15 to 30 minutes. The warning is issued when either large hail or damaging wind has been reported, or Doppler radar indicates a thunderstorm is either currently producing, or could soon produce, 1″+ diameter hail or 58+ mph wind. Keep in mind, severe thunderstorms can produce tornadoes. Most importantly, it is the time to TAKE ACTION.
Take shelter indoors immediately. Stay away from windows as high winds or debris could cause windows to break and stay off porches. Avoid contact with corded phones and devices including those plugged in to electric for recharging. Cordless and wireless phones not connected to wall outlets are OK to use. Do not seek shelter from thunderstorms under trees. Avoid hilltops, open fields, the beach, or a boat on the water. You can find additional thunderstorm safety information on this page from FEMA.
Severe Thunderstorm Warnings are issued for individual storms, known as storm-based warnings or polygon warnings. However, for most, the warning is displayed for counties. Make sure you know which county you live, work, and frequent so when a warning is issued, you know if you are included in the warned area.
SEVERE THUNDERSTORM WATCH
A Severe Thunderstorm Watch is issued by the Storm Prediction Center. It is meant to outline an area where an organized episode of severe thunderstorms are expected in the next two to eight hours.
A Severe Thunderstorm Watch is your “heads up” alert. Often there is not an immediate threat, however it is time to prepare in case a Severe Thunderstorm Warning is issued within the next couple of hours.
This is the time to plan where to take shelter if a Severe Thunderstorm Warning is issued. Make sure to enable your way of receiving Severe Thunderstorm Warnings. Also, it is the time to keep an eye on weather conditions and have a way to monitor weather conditions – monitoring the latest from The Weather Authority.