eli5: How do storms you see moving on a weather radar app move in the opposite direction of the prevailing winds in the region? Why are they not pushed ahead by the wind and going with it?

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Gulf Coast U.S. for reference. Looking at a radar app and the Windy app today, I noticed the wind was blowing to the north but the line of thunderstorms was moving south. Help me understand this please!

In: Planetary Science

2 Answers

Anonymous 0 Comments

Storms are more of an “event” instead of a “thing”. There isn’t a chunk of “storm air” that is being blown around. Instead you have cooler, more dense air masses falling under the force of gravity to displace warmer, less dense air masses below them. This movement of air is wind, and as air masses change temperature and density the amount of water vapor they can hold will change which can result in it condensing and falling out as precipitation.

That event of shifting air masses and precipitation can move “upwind” because it isn’t tied to a particular patch of air.

Anonymous 0 Comments

Sometimes thunderstorms will kick off along the edge of something and eat their way into that air. For example, the Sea Breeze along the coast is due to the warm air over land rising and being replaced by the cooler air over the water. Under the right conditions, this moist air moving over the warm land will grow into thunderstorms, which can then move toward the coast, against the sea breeze direction. They’re eating the moist air from the coastal water.