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Episode 2018-13 - Thunderstorms Part 2

I talk about a thunderstorm's lifecycle and other cloud formations.


  • Every thunderstorm needs: Moisture, unstable air (warm air that can rise rapidly), and lift (caused by cold or warm fronts, sea breezes, mountains, or the sun's heat).
  • The Thunderstorm Lifecycle
    • Developing Stage - In this stage, you get towering cumulus clouds indicating rising air. In this stage there usually isn't any rain. The clouds are raising up to 20 thousand feet. This stage lasts around 10 minutes and you may see some lightning.
    • Mature Stage - In this stage, the clouds could shoot over 40 thousand feet in the air. At this point, you will most likely have your rain, hail, frequent lightning, strong winds, or tornados. The storm will have a black or dark green appearance. On average these storms will last 10-20 minutes, but some will last much longer.
    • Dissipating Stage - In this final stage, the downdrafts dominate the storm. Rainfall will decrease. You could still get some strong winds and lightning.
  • Notable Cloud formations
    • The big one is the wall cloud. This is an isolation lower cloud attached to the rain-free base on the trailing side of a storm. For instance, if a storm is moving north or northwest then the wall cloud is on the south or southwest side. These clouds can last for 10 or more minutes. They will rotate, not always. The wall cloud is showing you where the updraft of the storm is. Think of it this way, all of the humidity on the ground is being pulled together into a cloud. You may see this rising motion of the clouds if you watch it. At this stage, it isn't anything dangerous. Once it starts to rotate, that is when the NWS wants to know about it. When it rotates, it could then become a tornado. I will cover tornadoes in another episode.
    • The Shelf Cloud (Which really looks more like a wall) is a low horizontal band of clouds attached to the base of clouds. Generally, a shelf cloud is on the leading edge of a storm. I also understand that you could get some strong winds from this type of storm. The shelf look is formed by turbulent winds.
    • Another neat formation is the roll cloud. It's a horizontal, tube-shaped cloud that is not attached to the other cloud features. This again is formed by winds.
    • This last formation, I debated where to place it, but I figured I'd include it here. This is a gust front or outflow boundary. This is usually associated with stronger storms. In fact, the outflow boundary could develop new storms. Wikipedia describes the outflow boundary as “a storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with the passage marked by a wind shift and usually a drop in temperature and a related pressure jump.”

Link/Picture of the Show


podcast/ddop/public/episode_201813.txt · Last modified: 2018/11/22 14:30 (external edit)