Go Back
Freezing temperatures, power outages as Tennessee residents clean up after deadly tornadoes Chevron right
Heavy rain, high winds causing havoc with late weekend travel on Eastern Seaboard. Click for forecast Chevron right

Ashburn, VA

39°F
Location Chevron down
Location News Videos
Use Current Location
Recent

Ashburn

Virginia

39°
No results found.
Try searching for a city, zip code or point of interest.
settings Let's Chat
Ashburn, VA Weather
Today WinterCast Local {stormName} Tracker Hourly Daily Radar MinuteCast Monthly Air Quality Health & Activities

Around the Globe

Hurricane Tracker

Severe Weather

Radar & Maps

News

News & Features

Astronomy

Business

Climate

Health

Recreation

Sports

Travel

Video

Winter Center

Top Stories AccuWeather Early AccuWeather Prime Astronomy Climate Travel Health Recreation Business Sports
Special Weather Statement

News / Severe Weather

When does tornado season hit its peak across the US?

By Alex Sosnowski, AccuWeather senior meteorologist

Published Mar 31, 2020 3:08 PM EST

Copied
McCook tornado near Culbertson, NE

A tornado tore through a field between McCook and Culbertson, Nebraska, Friday evening, May 17, 2019. (Twitter / @Sturms112010)

@Sturms112010

Tornadoes can occur year-round anywhere over the lower 48 of the United States, but the spring to summer period is prime time for severe thunderstorms that spawn the violent swirling columns of air.

Building warmth and surging humidity are key ingredients for thunderstorms which, when severe, can evolve to produce tornadoes.

"Severe thunderstorms will typically form when we get warm, moist air from the Gulf of Mexico clashing with cool air from Canada and sometimes dry air from the deserts," AccuWeather Meteorologist Brett Edwards said.

"We often see the most tornadoes develop from central Texas, northward through the Nebraska and Iowa," Edwards said, adding that this area is often referred to as "Tornado Alley."

Static severe thunderstorm / tornado outbreak setup

In order for severe thunderstorms to form, there must be a mechanism for air to rise in vigorous fashion. As a column of air rises through the atmosphere, it cools and causes moisture within to form the towering clouds we see as thunderstorms. The more moisture available and the cooler the air is aloft, the more efficient and potentially the more violent this process is. A push of dry air or cooler air from the outside can also intensify this process.

Any time there is a surge in temperature and humidity levels, combined with the approach of cooler and drier air thunderstorms can erupt. The most dramatic time of the year for this is in the spring to early summer.

"Traditionally, severe weather and tornado season peak from April through June," Edwards said.

"May has the most tornadoes, but April often has the strongest tornadoes and June has the most number of days with tornadoes," Edwards explained.

Areas of the country that typically warm up the fastest with an ample supply of moisture are usually the most likely areas for early-season severe thunderstorms and tornadoes.

CLICK HERE FOR THE FREE ACCUWEATHER APP

The peak for tornadoes during April extends from the South Central and Southeastern states to the Ohio Valley. This region often experiences surges in warmth and high humidity early on in the season.

During April and May, much of the Pacific coast states experience a pulse in locally severe thunderstorms and tornadoes. This occurs as winter's chill eases and there is still moisture left over from the Pacific storm season. Severe thunderstorms tend to diminish late in the spring and summer since moisture is often lacking during that time.

Farther to the east during May, the risk of tornadoes expands to much of the southern Plains, more of the Midwest and the southern Appalachians due to expanding and more persistent warmth and higher humidity.

The Florida Peninsula also experiences a peak in May as weak fronts tend to stall over the region, the dry season has ended and humidity levels surge as well as an uptick in sea breeze-induced thunderstorms. During the summer months, the tornado risk lowers somewhat over the Florida Peninsula as the northeast trade winds increase from the Atlantic and regulate the temperature. However, during the summer and autumn, tropical storms can also unleash tornadoes in Florida and much of the Deep South.

It is during the summer months when the Northeast, northern Plains, Rockies and Desert Southwest typically experience the greatest risk for tornadoes annually.

Related:

The difference between tornado watches and warnings
How to prepare for severe weather in the age of social distancing
How to stay safe when tornadoes strike at night

In New England, for example, the region is surrounded by chilly water on the eastern and southern side during the spring months. The chilly water tends to suppress thunderstorm activity. Once the Atlantic warms up, the risk of severe weather increases in the region.

Despite being void of any large bodies of water, it takes longer for the northern Plains and Rockies to warm up due to the region sitting at a higher elevation and reaching higher in the atmosphere as a result.

In the desert areas of the Southwest, the risk of tornadoes increases once the North American monsoon begins, which is when a persistent southerly flow of moisture develops, in early July. The moisture more typically fuels spotty, drenching thunderstorms, more so than tornadoes, however.

Even though there is a notable peak time of the year for tornadoes across different regions, twisters can occur any time of the year, given the right conditions. There have even been some rare instances of tornadoes in Alaska and Hawaii.

Strong storm systems can even trigger tornadoes in winter if they bring warmth, moisture, cool air and strong winds aloft together in such a way as to spur thunderstorm formation and escalate those storms to severe levels.

The Deep South tends to experience a secondary but significant uptick in severe weather during the midautumn as storm systems begin to strengthen and tap warm, moist air from the Gulf of Mexico, prior to the spread of cold, dry air from Canada during the winter.

"If there is rotation within the storm, then the stage is set for tornadoes to form," Edward said.

The mechanism as to how tornadoes form is complex and not fully understood with changing and evolving theories. Although the increasingly widespread use of Doppler radar during the 1980s and 1990s, which allows meteorologists to see wind patterns inside the thunderstorms, has taken the study forward by leaps and bounds.

The increase in real-time storm spotters and instantaneous video has also given the science a tremendous boost.

The general consensus among meteorologists is that air that normally rotates gently in the horizontal is twisted to the vertical in severe thunderstorms. The change in wind direction and speed at different levels of the atmosphere is known as wind shear, which can add spin and help this process along.

In some cases, the entire thunderstorm begins to rotate due to strong wind shear.

Next, strong updrafts and downdrafts within the thunderstorm can then cause a small column of air to spin at an increasingly rapid pace and produce a funnel cloud. Once this funnel extends to the ground, a tornado is born.

In terms of the deadliest forms of weather phenomenon, heat kills more people per year, on average, than tornadoes in the United States, according to the Centers for Disease Control and Prevention (CDC).

Heat kills an average of 130 people per year, based on a 30-year average using CDC data from 1989 to 2018. The second deadliest form of weather is flooding with 87 fatalities per year, followed by tornadoes at number three with 69 deaths per year.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.

Report a Typo
Comments that don't add to the conversation may be automatically or manually removed by Facebook or AccuWeather. Profanity, personal attacks, and spam will not be tolerated.
Comments
Hide Comments

Top Stories

Weather News

Freezing temps, power outages as tornado cleanup begins

Dec. 10, 2023
Weather News

At least 6 dead after tornadoes rip through Tennessee

Dec. 10, 2023
Severe Weather

Heavy rain, high winds causing havoc along the Eastern Seaboard

Dec. 10, 2023
Show more Show less Chevron down

Topics

Top Stories

AccuWeather Early

AccuWeather Prime

Astronomy

Climate

Travel

Health

Recreation

Business

Sports

Top Stories

Weather News

Freezing temps, power outages as tornado cleanup begins

1 hour ago

Weather News

At least 6 dead after tornadoes rip through Tennessee

1 hour ago

Severe Weather

Heavy rain, high winds causing havoc along the Eastern Seaboard

6 hours ago

Winter Weather

Snow, cold winds to follow rainstorm in Northeast

6 hours ago

Astronomy

Geminids to sparkle with over 100 meteors per hour Wednesday night

8 hours ago

More Stories

Featured Stories

Live Blog

Photo Blog: Mount Etna's fire and ice'

LATEST ENTRY

Fire and ice: Mount Etna spews lava onto snowy peak

2 days ago

Astronomy

Astronaut Frank Rubio lost a tomato in space. His colleagues found it

2 days ago

Travel

Almost half the men surveyed think they could land a passenger plane

4 days ago

Travel

The stunning 30-hour train ride that sells out in minutes

2 days ago

Weather News

Treat your elf to a stay in Santa Claus’ cabin this Christmas season

5 days ago

AccuWeather Severe Weather When does tornado season hit its peak across the US?
Company
Proven Superior Accuracy About AccuWeather Digital Advertising Careers Press Contact Us
Products & Services
For Business For Partners For Advertising AccuWeather APIs AccuWeather Connect RealFeel® and RealFeel Shade™
Apps & Downloads
iPhone App Android App See all Apps & Downloads
Subscription Services
AccuWeather Premium AccuWeather Professional
More
AccuWeather Ready Business Health Hurricane Leisure and Recreation Severe Weather Space and Astronomy Sports Travel Weather News Winter Center
Company
Proven Superior Accuracy About AccuWeather Digital Advertising Careers Press Contact Us
Products & Services
For Business For Partners For Advertising AccuWeather APIs AccuWeather Connect RealFeel® and RealFeel Shade™
Apps & Downloads
iPhone App Android App See all Apps & Downloads
Subscription Services
AccuWeather Premium AccuWeather Professional
More
AccuWeather Ready Business Health Hurricane Leisure and Recreation Severe Weather Space and Astronomy Sports Travel Weather News Winter Center
© 2023 AccuWeather, Inc. "AccuWeather" and sun design are registered trademarks of AccuWeather, Inc. All Rights Reserved.
Terms of Use | Privacy Policy | Cookie Policy | Do Not Sell or Share My Personal Information checkmark Confirmed Not Selling Your Data

We have updated our Privacy Policy and Cookie Policy.

I Understand

Get AccuWeather alerts as they happen with our browser notifications.

Notifications Enabled

Thanks! We’ll keep you informed.

Let's Chat –
AccuAssistant™
ComScore