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Understanding Your Thunderstorm Forecast Before You Ride Or Run

And what to do if Mother Nature interrupts your workout.

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The weather forecast calls for a chance of thunderstorms, but all you can see outside are fluffy white clouds. Do you head out for your long ride or run, or play it safe and stay indoors? To make sense of the weather forecast, we called on professional triathlete Liz Baugher, who holds a master’s degree in atmospheric science and works for the American Meteorological Society.

Breaking down the terminology can go a long way in understanding your weather risk. “Meteorologists use forecasts to predict the chance that it will rain, but we also factor in the area for which it has a chance to rain,” explained Baugher. “We frame this using the term PoP, or the probability of precipitation.”

If you open your weather app on your smartphone and see a 60% chance of thunderstorms for the day in your town, that’s the PoP for the specific area—in other words, a 60% chance storms will hit in your region. Forecasters can get more specific and use terms such as “isolated”, “scattered”, and “likely”: 

  • Isolated generally means that the PoP is low, hard to predict, and can depend on the region of your forecast area. 
  • Scattered means there is a roughly 50-50 chance and also can vary within the region.
  • Likely means there is a high PoP score.

“You also want to keep in mind that a chance of thunderstorm does not always mean it will thunderstorm the whole day,” said Baugher. “You will want to check the forecast for the approximate time that it will occur. For the most part, you’ll see in the summer that storms pop up in the afternoon because of heating throughout the day. These storms can accelerate quickly and can be strong. If you’re planning to do an afternoon workout, you’ll want to make sure to you check the forecast before you go. You’ll also want to check a radar to see if there is any rain or other storms in the localized area you are heading.”

Assessing the terminology used in the thunderstorm forecast, along with the radar, can help you make an informed decision about heading outside for a workout. If in doubt, it’s best to err on the side of caution, as getting caught outside when rain, wind, and lightning is present is not something to take lightly. Poor visibility can make it difficult for vehicles to see you while riding or running, and lightning poses an extreme hazard. On average, 28 people are killed by lightning in the United States each year, and hundreds more are injured.

Signs a Storm is Approaching

If you’re already outside for your workout, it’s important to stay on the alert for weather changes, especially if storms are in the forecast. Tell-tale signs of storms approaching include: 

  • Dark, thick clouds developing
  • Winds speeding up
  • Feeling a drop in temperature

If you see these signs, be prepared to take cover, as storms can gather quickly. An easy-to-remember maxim: “When the thunder roars, go indoors.”

“If thunderstorms develop, count the seconds between the flash of lightning and the bang of thunder to estimate the distance between you and the lightning strike,” said Baugher. “If the time between the lightning flash and thunder is 30 seconds or less, you should seek shelter.”

What To Do If You Get Caught in a Thunderstorm

“When it comes to any kind of outdoor workout, you will want to stop your workout,” said Baugher.

Water is a conductor of electricity, so if you are swimming in an outdoor pool or open water, get out immediately. Find shelter inside your car or a nearby building. Indoor pools may be safe, since most are built with electric ground wiring, but always follow the guidance of lifeguards facility staff.

If you’re out on a ride or run, find a safe shelter immediately, whether it’s a sturdy building or inside your car. Baugher said to avoid sheds, picnic shelters, baseball dugouts, and bleachers if possible, as lightning can travel through metal frames and any metal wires or bars in concrete walls or flooring. You also want to avoid tall objects and isolated trees; seeking shelter under a thicker growth of small trees is preferable. If you are in a group setting, make sure to spread out.

If at any point during a lightning storm you feel your hair stand on end, experience a tingling sensation on your skin, or hear crackling noises, immediately assume the lightning-safe position. 

  • Crouch to the ground with your feet together and the weight on the balls of the feet.
  • Lower your head and cover your ears. 
  • If you can, place your hands on your forehead and elbows on your knees.
  • Take a deep breath and try to relax.

Storms will generally pass within 30 to 60 minutes. When you no longer see lightning or hear thunder, it is probably safe to continue your workout. However, Baugher advised checking a weather app on your smartphone (such as The Weather Channel or RadarScope) to ensure there are no more storm cells present on the radar. Though you may feel anxious about finishing that long ride, it’s best to make your decisions based on the weather, not your workout plan. There’s no shame in pulling the plug on a workout when Mother Nature isn’t cooperating.

“By all means, just be cautious,” said Baugher of assessing a thunderstorm forecast and situation. “No workout is worth your life.”