Weather Impact Day versus a Weather Alert Day
I had a great conversation this morning as to why today wasn’t a Weather Authority Alert Day. I thought I would take the highlights from this conversation to answer the same question for you and explain the difference between the two terms.
Let’s start with today and tonight’s forecast and the Impact Day. What makes an Impact Day?
Criteria for an Impact Day:
- More than 3 hours of rain
- Freeze or Hard Freeze
- Heat Advisories
- Strong wind, non-severe
- Local storms with a limited impact
These are the types of weather that could have us canceling or changing our plans or adding protection to our plants and gardens. You will often hear us referring to these days as nuisance or disruptive.
What is a Weather Authority Alert Day? These are days that the effect of local weather could leave some with storm related damge.
Criteria for a Weather Authority Alert Day or a Severe Weather Alert Day:
- An increasing and verified moderate threat of Severe Weather
- 5 hours or more of rain with flooding
- Watches and Warnings issued
- Wind over 40 mph, but not severe levels
- Heat Warnings
Severe Weather Alerts - the highest level of our alerts:
- The Particularly Dangerous Situation (PDS) wording is used in rare situations when long-lived, strong and violent tornadoes are possible. This enhanced wording may also accompany severe thunderstorm watches for intense convective wind storms.
- Tropical Storm
- Hurricane
- Tornado
- High Risk of area-wide severe storms.
What is a Severe Storm? To be considered a Severe Thunderstorm: capable of producing a tornado, winds of at least 58 mph and/or hail at least 1″ in diameter.
Guide for determining hail sizes:
less than 0.50″ Pea
0.50″ - Marble/Mothball
0.75″ - Dime/Penny
0.88″ - Nickel
1.00″ - Quarter
1.25″ - Half Dollar
1.50″ - Walnut/Ping Pong
1.75″ - Golf Ball
2.00″ - Hen Egg
2.50″ - Tennis Ball
2.75″ - Baseball
3.00″ - Tea Cup
4.00″ - Grapefruit
4.50″ - Softball
At the root of an Impact Day or an Alert Day is your time and safety. With an Impact Day, we are not going to waste your time with an abundance of updates and alerts.
However, if there is something to be Alert about because of impending danger due to storms, we will remind you through updates on-air, online and our Weather Authority app.
In a nutshell, weather on an Impact Day could have you changing your plans. Weather during a Weather Authority Alert or a Severe Weather Authority Alert could change your life.
I hope this helps. If you have questions feel free to reach out: rnunn@wjxt.com