Severe means damaging wind over 58mph, hail larger than an inch, or a tornado. By definition “severe” does not account for lightning or how loud or rainy a thunderstorm is. A severe storm can occur by itself on a day of ordinary thunderstorms or it can occur in an outbreak that covers large areas. When severe or regular thunderstorms move as a group in a line, that is called a squall line. When a squall line is unusually persistent, large and strong with continuous bursts of wind it may become a derecho. Intense lightning, by itself, does not make a storm “severe” by meteorological definition, although most people might call it severe as in strong. That causes confusion. Similarly, flash flooding can follow regular thunderstorms or even just a long period of heavy rain without any thunderstorm.
A Watch means there is a potential for a certain type of weather and a Warning means it is happening or very likely to happen.
Watches cover large areas of a state or multiple states and last for many hours. Tornado Watches and Severe Thunderstorm Watches are issued by the Storm Prediction Center, one of the branches of NOAA. Flash Flood Watches are issued by the Weather Prediction Center, another branch of NOAA.
PDS means Particularly Dangerous Situation and this designation is used with an existing Watch. Expect Warnings for very powerful severe thunderstorms or large, long-track tornadoes. This is used often with high risk scenarios and sometimes with moderate risk. Take it seriously and be ready to put your safety plan into action.
Warnings cover counties or portions of counties in an area known as a polygon. That’s simply a multi-sided box. The polygons often get larger in the direction that a storm is moving because uncertainty of where it will be increases with time.
Warnings for Severe Thunderstorms, Tornadoes and Flash Floods are issued by local offices of the National Weather Service. Severe Thunderstorm and Tornado Warnings typically last 30 to 45 minutes. Flash Flood Warnings may last a couple of hours. There are no warnings for just for lightning because lightning and thunder plainly announce their presence.
There is a special case for a warning when a tornado is known with certainty to be on the ground with a high potential to take lives and that is Tornado Emergency.
Watches are typically issued first, followed by Warnings. If only one or a few severe storms occur Warnings are issued without a Watch.
When there’s a risk of severe weather in our area you’ll hear it on WKRG-TV, usually a day or two in advance and certainly on the day of it. These are called Outlooks because they give a general idea rather than a forecast for an area.
Here are the 5 Outlook terms that give a relative risk in severe weather: Marginal; Slight; Enhanced; Moderate; and High. These indicate coverage and impact.
Marginal means stay updated to the forecast because a few thunderstorms may become severe.
While Slight may sound like not much risk it means there is a risk of severe thunderstorms or tornadoes greater than that on an ordinary day of thunderstorms. Be aware as you go through your day.
Enhanced risk tells you that some severe thunderstorms are more likely than not to form. Be alert.
Moderate risk almost always is followed by Watches being issued and severe weather occurring. You should have a safety plan.
High risk generally means severe weather will occur within Watches producing significant impact over a large area, usually from tornadoes. You must plan your day around this threat.
You can also watch our streaming webcasts which are updated at least twice a day for information if you miss the news. If we don’t mention a risk then the risk is low.
When we have Watches and Warnings you will first see the text at the bottom of your TV screen and if it is a Tornado Warning or a Flash Flood Warning we’ll interrupt the program to give you details.
All businesses, schools, churches, and other areas where people gather need multiple ways of receiving severe weather information. Many of these facilities have rules against watching TV but in the case of severe weather it would be wise to allow TVs. While TVs might interrupt the regular routine when there’s a threat of extreme weather TVs provide comfort and guidance through immediate information. At least one person should be assigned the task of keeping up with the weather on TV to keep everyone else informed.
Get yourself a weather radio too as another source of information, Watches and Warnings. Most local stores that sell radios and small home appliances carry them. Buy a weather radio with the “S.A.M.E.” feature which allows you to program it for a single county. Some weather radios that have “S.A.M.E.” will still sound an alarm for a Special Marine Warning if you live in a coastal county which most people don’t care for. Others come with optional attachments for bed shakers, strobe lights, and external horns, so make sure what you are buying fits your needs. Some are portable with batteries and others have an optional hand crank in case of total power loss.
Use our interactive radar to see if you are in the Watch or Warning area.
Our free smart phone weather app shows you the outline of the Watch or Warning too. Along with showing the radar and motion of storms, it also sends a notification. There are many other free or pay smart phone apps that do this too. On the News 5 weather app, you also see video webcasts updated at least twice a day.
When there is local severe weather we put our focus and energy on where the worst conditions are or who is most at risk in the 13 counties we cover so if you don’t hear your community mentioned that’s a good thing.
Nobody can tell you far in advance exactly what the weather will be where you live. Severe storms can grow and fade in 20 to 30 minutes. Even with long track severe storms you don’t typically have more than a half hour to know if one might be approaching you. Like most severe weather situations in this region, most people will not experience the worst that can happen but you still need to be alert.
Check your county website or call to find out if they offer free email or phone alerts too, for weather and for other community emergencies.
Google has a map that plots all severe weather Watches and Warnings in the U.S.
Remember that even with “ordinary” thunderstorms on a day when there is no outlook for severe weather, a single lightning strike can knock out power to a community or a single wind gust can topple a weakened tree to block traffic or land on a house. This makes it impossible to confidently answer the question “how bad will the weather be where I am?”!
When you are traveling on the road listen to a local radio station (like NPR) that is likely to pass along weather alerts immediately. You’ll need to know what county you are in. Some phone weather alert services use GPS to trigger when you are in a warning polygon. The best ones, like the free News 5 Weather app, have “Push Alerts” where your phone will chime when you are located in the warning.