What Are the Main Types of Thunderstorms?
Thunderstorms range from single-cell storms that live about 30 to 60 minutes, to multicell clusters and squall lines that last for hours, to rotating supercells that produce most strong tornadoes and giant hail. The largest systems, mesoscale convective systems, can cover several states overnight and sometimes produce derechos, long swaths of damaging straight-line wind.
This is my favorite unit, and not just because the app has Lightning in its name. We start with one simple pop-up storm and build all the way to supercells and derechos. Then we get into how a cloud makes lightning and how to keep your family safe from it. Living on Florida's Space Coast, I see a lot of these storms. You will learn to read them too.
What You’ll Learn
- The three stages of a thunderstorm and why weak-shear storms die out
- How downbursts and microbursts cause damaging straight-line winds
- How squall lines, shelf clouds and bow echoes work
- What makes a supercell rotate and how to spot a hook echo and wall cloud
- How MCSs grow overnight and what makes a derecho
- How lightning forms, what causes thunder, and how to estimate distance
- The NWS lightning safety rules, including the 30-minute rule
Lessons In This Unit
- 7.1The Life Of A ThunderstormA thunderstorm has three stages. In the cumulus stage, updrafts build a towering cloud with no rain yet. In the mature stage, rain falls, creating a downdraft beside the...Beginner · 9 min
- 7.2Multicell Clusters And Squall LinesA squall line is a long line of thunderstorms, often 50 to several hundred miles long, usually ahead of or along a cold front. It has a band of intense storms at the front edge...Intermediate · 9 min
- 7.3Supercells: The Rotating ThunderstormA supercell is a thunderstorm with a deep, persistent rotating updraft called a mesocyclone. Supercells form where strong instability meets strong wind shear. They are only a...Intermediate · 9 min
- 7.4MCSs, MCCs And DerechosA derecho is a widespread, long-lived windstorm produced by a fast-moving group of thunderstorms, usually a large bow echo. It leaves a long swath of straight-line wind damage,...Advanced · 10 min
- 7.5How Lightning WorksLightning forms when collisions between graupel and small ice crystals inside a thunderstorm separate electrical charge. The updraft carries light, positively charged crystals...Intermediate · 9 min
- 7.6Lightning SafetyGo indoors as soon as you hear thunder, because you are close enough to be struck. Shelter in a building with plumbing and wiring or a hard-topped metal vehicle with windows...Beginner · 9 min
Questions People Ask
What makes a thunderstorm severe?
The NWS calls a thunderstorm severe if it produces hail 1 inch or larger, wind gusts of 58 mph or higher, or a tornado.
What is the difference between a supercell and a regular thunderstorm?
A supercell has a deep, persistent rotating updraft called a mesocyclone. Ordinary storms do not rotate this way and usually live much shorter lives.
How close does lightning have to be to strike you?
If you can hear thunder, you are close enough to be struck. Lightning can reach 10 miles or more from the storm.
Learn the storms, love the storms, and when thunder roars, go indoors. — Jen
