The United States leads as the country with the most tornadoes, with an average of 1200 individual tornadoes each and every year.
Whilst tornadoes in the US can happen at any time of year, they most often occur during the hot months of early summer and late spring.
During these months tornadoes form when warm, humid air collides with cold, dry air. This is when some of the largest thunderstorms on earth occur.
This begs the question, do tornadoes come from thunderstorms?
In short, yes. All tornadoes start from thunderstorms, but not all thunderstorms form tornadoes. The type of thunderstorm that forms tornadoes is known as a supercell, these are some of the largest and most violent on earth.
Do Tornadoes Really Come From Thunderstorms?
Tornadoes develop from severe thunderstorms when perfect conditions allow. The ingredients needed for a tornado are warm, moist, and unstable air as well as cold fronts and updrafts.
Whilst it’s true that all tornadoes come from thunderstorms, it’s important to note that not all thunderstorms form tornadoes.
Conditions must be just right for a tornado to form, which is why they happen most often at certain times of the year and in certain areas of the planet.
The Central United States during the months of June and July are tornado hotspots. The warm, humid air from the equator meets the cold, dry air from Canada and the Rocky Mountains.
These conditions can be just right for forming some monster thunderstorms, which can then form violent tornadoes.
What Are The Chances Of A Thunderstorm Forming A Tornado?
Even though all tornadoes are produced from thunderstorms, as few as 20 percent of all supercell thunderstorms actually produce a tornado.
The good news is that around 90 percent of tornadoes that occur across the globe are weak, making it rare that an EF4 or EF5 tornado will form at all.
Many tornadoes are short-lived and don’t last longer than 20 minutes before running out of steam, whereas stronger tornadoes can last for hours.
Can Tornadoes Form Without Thunderstorms?
Tornadoes rely on thunderstorms in order to push cold air over the warm air and form. However, landspouts and waterspouts are weak forms of tornadoes that can sometimes form without a severe storm.
Some weak storms are capable of producing what is commonly referred to as “gustnado” or “landspouts”.
These small tornadoes can sometimes spawn without wind speeds reaching 58mph, which is the threshold for a storm to be defined as severe.
These much smaller tornadoes can form in less severe storms, but any storm that produces a tornado has defaulted to a severe storm.
That said, you’ll never see an actual tornado forming without a rather large thunderstorm as the conditions of the storm are what allow the tornado to form.
The two come in pairs, and whilst you may see waterspouts or landspouts these are different from tornadoes.
What Part Of A Thunderstorm Does A Tornado Come From?
The part of a thunderstorm that a tornado comes from is known as a rotating updraft. This is a key component in the development of a supercell thunderstorm and is vital for tornadoes to form.
There are many ideas on how rotating updrafts begin, one way a column of air can begin to rotate is from wind sheer.
The warm air that rises through the colder air causes an updraft, and if winds vary sharply in speed or direction this can begin the rotation of the updraft.
As the rotating updraft (also known as a mesocycle) starts to draw in more warm air from the thunderstorm, it increases its rotation speeds and becomes more powerful.
Water droplets from the mesocyclone’s moist air form a funnel cloud and once this descends from the ground and makes contact, it becomes a tornado.
Can Tornadoes Form Without Lightning?
Every thunderstorm produces lightning, and being that every tornado is formed from a thunderstorm, it would be impossible for a tornado to form without lightning.
However, as mentioned earlier there are smaller variations of “tornados” such as dust devils, waterspouts, and landspouts that do not require thunderstorms to form.
Therefore these smaller weather events can form without lightning, but an actual tornado needs a thunderstorm to form.
So, do tornadoes come from thunderstorms? Yes, they most certainly do. All tornadoes are formed from a thunderstorm, aside from the smaller landspouts and waterspouts.
Thunderstorms provide the optimal conditions that all tornadoes need to form, which is a combination of warm, humid air colliding with cold, dry air.
The colder air is pushed over the warm air which causes an updraft that begins to rotate if winds vary in speed and direction.
Dust devils are also a very small type of tornado which can occur without a thunderstorm, but these are short-lived and usually last only seconds to minutes.
Thanks for taking the time to read this post and I hope you’ve learned something new about why all tornadoes need thunderstorms to form.
Until next time!
Hey, I’m Sam – the founder of GustyPlanet. I’ve had a fascination with all things weather for as long as I can remember. I witnessed my first tornado at the age of 6, and since then became an avid storm chaser that is hooked on learning as much as I can about extreme weather. This blog was created to share my knowledge and to expand and delve deeper into the wonderful world of weather phenomena. I hope you enjoy your stay here and thanks for visiting.