GroundTruth

- GroundTruth
  
  For more than 20 years Earth Networks has operated the world’s largest and most comprehensive weather observation, lightning detection, and climate networks.
  
  We are now leveraging our big data smarts to deliver on the promise of IoT. By integrating our hyper-local weather data with Smart Home connected devices we are delievering predictive energy efficiency insight to homeowners and Utility companies.
- GroundTruth
- WeatherBug
  - Consumer
  - Corporate
- WeatherBug
  - Consumer
  - Corporate

Thunderstorms are some of the most widely recognized and frequent types of storms, which occur mostly during the spring and summer seasons. They are widely understood as storms that can bring heavy rain and cause major damage to an area. However, what is often less understood is the difference between a typical and a severe thunderstorm.

Thunderstorms are simply classified as rain showers where thunder can be heard; and since thunder is the production of lightning, this means all thunderstorms produce lightning. However, most bolts don’t reach the ground. Thunderstorms need three key ingredients to properly form: moisture, an unstable atmosphere, and a lifting mechanism.

A storm’s source of moisture stems from the oceans; warm ocean waters will lead to more evaporation and allow for more severe thunderstorms. An unstable atmosphere is one where air continues to rise upward, rather than doing nothing. Thunderstorms require warm, moist, rising air; the more moisture that rises, the more likely it is that a thunderstorm will form. Air, however, cannot rise without a lifting mechanism. Warm air is less dense than cold air; therefore cold air will sink under warm air and lift it up. This lifted air can be carried great distances inland by upper level winds and bring plenty of hazards many miles away from their source.

In addition to a thunderstorm’s three main ingredients, they also have five main hazards: hail, winds, lightning, tornadoes and flooding. As a thunderstorm grows in intensity, more and more air is sucked into the storm, almost like a vacuum. This air, known as updrafts, helps fuel the thunderstorm further and brings moisture to the upper atmosphere, where the air is much colder. At this level, condensing water can freeze and form hail. Stronger updrafts produce larger hailstones, and like lightning, most of the hail that does form simply stays at the top of the storm, but sometimes hailstones find their way to the surface when they are caught in downbursts.

When the storm reaches its mature stage, air is forced downward out of the system. This air, known as downbursts, can bring heavy rain and cause damaging winds. If the storm is potent enough, winds can shoot out up to 170 mph. However, most storms don’t reach that level of intensity, and produce winds between 40 and 50 mph. Downbursts have shown their damaging potential in the past. Several people are killed each year in accidents resulting from downbursts. They can blow over mobile homes, knock over unstable buildings, rip the rooves off of buildings, blow over trees, etc. In fact, downbursts have deadly consequences. In 1985, Delta flight 191 crashed just one mile away from Dallas/Fort Worth International Airport. The lack of specific training and procedures for avoiding thunderstorm hazards such as downbursts were a contributing factor in the crash. Automated voice notification system and new pilot training designed to react to microbursts were implemented after the crash.

Lightning is arguably the most dangerous thunderstorm hazard. It is the result of the connection between opposing electric charges between clouds or between clouds and the ground. Strikes are more likely to occur on taller objects such as trees or skyscraper, but an open field can be struck if the charges build up enough. A lightning strike can occur up to 10 miles from the storm; if you can hear thunder, then you are at risk of being struck. In the past decade, lightning has killed approximately 30 Americans and injured 250 more. When lightning strikes, the air around it rapidly expands, producing the sound of thunder, which can be heard up to 25 miles away from the discharge.

Tornadoes and floods are the least common hazards associated with thunderstorms, but they can happen if the conditions are correct. Tornadoes are most frequent along the tornado belt, located in the Midwest and Plains of the U.S. Flooding on the other hand usually occurs when strong thunderstorms and heavy rain follow each other back to back. When this happens, rivers have an increased risk of reaching their flood stages and overflowing. Remember, the most important rule of thumb when you encounter a flooded roadway is to “Turn Around, Don’t Drown!”

Thunderstorms can have most of the elements above, and still not be classified as severe, so what separates the severe from the typical? A thunderstorm is considered severe when one or more of the following conditions have been met: hail size has reached or surpassed one inch, wind speeds have reached or surpassed 57.5 mph (50 knots), or a tornado has formed. Most severe thunderstorms appear along the Plains and eastern tier of the U.S. during the spring and summer. Here, warm, moist air is sent in from the Gulf of Mexico and is then intercepted by eastbound cold fronts. It is important to stay ahead of storms during this time of year; heeding the warnings can ultimately save your life.

Source: The National Severe Storms Laboratory

- Live Radar
- - Weather Details
- Forecast
  
  }
- Featured Videos
- Air Quality

What Is A Severe Thunderstorm?