Severe weather: A guide to accurate weather forecasting

By The Weather Company

Severe storms affect business operations and consumers everywhere, costing an average of USD 10 billion* in damages and taking about 500 lives each year. Constituents rely on weather data to assess how to prepare for storms.

Meteorologists are tasked with providing weather predictions to their viewers to help them make the most informed decisions. Accurate weather data is an important component in getting viewers the information they need to better prepare communities with recommendations on how to remain as safe as possible during severe weather events.

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What is severe weather?

When discussing the weather, forecasters often cite the state of the atmosphere, including elements such as temperature, clouds and wind. Severe weather refers to the dangerous effects created by these changes in the atmosphere that result in tornadoes, extreme thunderstorms or blizzards.

Severe storms—often packed with heavy rains, strong winds, hail and lightning—can wreak havoc in a short time. When these fast-moving, highly localized storms move through a region, people and businesses need to be aware and take swift action.

Across industries, The Weather Company, an IBM Business, has the tools necessary to provide timely, accurate data that helps businesses keep employees safe, better protect assets and convey vital information effectively. Our tools help you and your business prepare for the storm and react faster, all while minimizing disruptions and impacts using severe weather forecasting.

The effects of climate change on storms

As the atmosphere warms, the effects of violent storms are becoming more extreme. An analysis by Carbon Brief* revealed that 70 percent of the 405 extreme weather events and trends included in their map of attribution studies were found to be made more likely or more severe by human-caused climate change.

In August 2020, Hurricane Isaias* wreaked havoc as it traveled along the East Coast, causing damage that had not been seen since Hurricane Sandy.* In California, the wildfire season is beginning earlier and ending later. California exceeded 4 million acres burned by wildfires in 2020. More than 8,200 fires have consumed more than double the previous record, fire officials said.*

severe weather

Severe weather resulting in a tornado

Forecasting severe weather

There are various tools in a meteorologist's toolkit to predict when violent storms are coming, including partnerships across the world and improvements in forecasting models.

Gathering weather data

Observing stations

In order to gather the vast amounts of data needed to make accurate weather predictions, observing stations are located around the globe. Many of the best gathering stations are located at airports, which require accurate weather information to keep passengers and crew safe during takeoff and landing. However, this data may not be localized enough for specific industries that require more granular details.

Weather information is shared from these stations across the globe through channels such as the United Nations. The World Meteorological Organization (WMO)* is an intergovernmental organization with a membership of 193 Member States and Territories, which verifies that the data gathered from these stations is consistent across nations.

Weather radar

Forecasting severe weather also involves utilizing weather radar to determine the motion and intensity of precipitation. Energy pulses or radar beams are sent into the atmosphere to determine the type (for example, snow or hail). Weather radar can also be used to determine wind speed and predict the formation of tornadoes. It’s a valuable tool for meteorologists.

Weather balloons

Weather balloons are used to gather information, such as temperature, from higher altitudes. Radiosondes are the devices attached to these balloons that gather the appropriate data. These balloons can reach as high as 24 miles* before disintegrating.

IoT data and sensors

With the emergence of IoT, there are ample opportunities to incorporate new data sources for accurate weather predictions. By leveraging IoT data and sensors from smartphones and self-driving cars, weather-forecast data can be more localized, which allows for more actionable insights and predictions for members of the community.

Forecasting the weather

Analog method

This method involves looking at historical weather and trends to find patterns and make predictions. However, this strategy can be difficult to accurately apply, because no two storms are the same. Additionally, with the emergence of climate change, weather patterns may change.

Trend forecasts

This forecasting method assumes that unless there is evidence to the contrary, weather patterns will continue to travel at the same speed and in the same direction.

Forecasting models

Forecasting models incorporate data sets, including inputs from weather radar and historical trends, to predict the course of the storm. With machine learning techniques, these models become more accurate over time. They run millions of equations to determine the course of the storm over short and long timeframes.

With the added capabilities from IBM, these models can extend beyond making storm predictions and translate these insights into actionable steps to help communities prepare (for example: helping utility companies determine which part of the grid may be most likely to face a power outage.)

Numerical Weather Prediction (NWP)

These particular models utilize mathematics and computers to make predictions on the weather based on the current state of the atmosphere. Though first conceptualized in the 1920s, this way of forecasting did not gain traction until the 1950s, when computers could be applied to mathematical formulas. In order to calculate the forecast for one day, millions of equations need to be solved. Before the advent of the computer, this was an impossible task for meteorologists to undertake.

An overview of violent storms

Severe thunderstorms 101

According to the National Weather Service*, a thunderstorm is considered severe when it creates hail that is 1 inch in diameter or has wind speeds 58 mph or greater. About 10 percent* of annual thunderstorms in the United States are categorized as severe. There are many dangerous aspects to these weather events, whether it be flash flooding, hail or lightning.

What is the most dangerous kind of thunderstorm?

Supercell thunderstorms are generally considered the most dangerous type. They are characterized by mesocyclones, which is a large region of rotation. Supercell thunderstorms can lead to tornadoes, produce large hail, and cause lightning.

What is lightning and what causes it?

Lightning is a huge spark of electricity that can be created within and between clouds, the air and the ground. When water and ice are moving within a cloud, pressure starts to build. This is due to the warmer air currents moving the elements upwards, and gravity forcing them back down. This charges the particles in the cloud. When the negative and positive particles in the cloud seek to neutralize, and the air acting as an insulator breaks down, there is a discharge of electricity, also known as lightning. On average, NOAA reports that lightning strikes the US about 25 million times* each year and injures hundreds in the process.

What are the types of lightning?

There are three main kinds of lightning. These include:

  • Intracloud
  • Cloud-to-cloud (CC) or intercloud
  • Cloud-to-ground (CG)

Intracloud lightning occurs within the thundercloud since the cloud has both negative and positive charges. This is the most common form of lightning. This discharge can also happen between clouds, which is known as cloud-to-cloud (CC) or intercloud lightning.

Cloud-to-ground (CG) lightning is the least common type of lightning and occurs when electricity strikes the ground. Although CG lightning can be either charge, it tends to be negative.

Wildfires: how are they related to severe weather?

Wildfires are heavily influenced by the climate. Due to droughts caused by climate changes, the risk of wildfires is expected to increase. Since 2000, an average of over 72,000* wildfires has destroyed 7 million acres of land each year in the US.

What causes wildfires?

Ten-fifteen percent* of wildfires occur naturally. This includes lightning strikes and severe thunderstorms. Eighty – ninety percent are caused by humans. Through dry vegetation, drought, and other factors related to climate change, these wildfires can quickly grow out of control.

An overview of tornadoes

Tornadoes are columns of rotating air that usually result from a severe thunderstorm. Wind speeds can reach up to 200 miles* per hour and the results of these weather events can be devastating for communities and business owners.

How are tornadoes forecasted?

In 1973,* tornadoes were first identified on weather radar before their formation. This breakthrough has allowed meteorologists to better prepare communities prior to these extreme weather events.

Meteorologists and other industry professionals can use Doppler radar to detect tornadoes. What is typically seen on the radar is a mesocyclone, which is an area of rotation often within a thunderstorm. These can span between 2 – 6 miles and can indicate the threat of an upcoming tornado.

What are the types of tornadoes?

There are two main categories of tornadoes—supercell and non-supercell. The first type develops from supercell thunderstorms and often results in more damage. Scientists do not yet understand why these kinds of tornadoes form, as only 20 percent* of all supercell thunderstorms result in these severe weather events.

An overview of blizzards

Blizzards are storms that result in vast amounts of snow with little visibility and 35 mph winds. In particular, driving conditions can be dangerous because whiteouts can hinder a driver’s ability to see, leading to accidents.

How are blizzards forecasted?

For blizzards to develop, wind needs to move quickly, temperatures must be low, and humidity must be high. If the temperature isn’t cold enough, snow will melt once it hits the ground. A wide variety of tools are used to forecast if a storm will become a blizzard and the rate of precipitation, including satellites and Doppler radar. Weather forecast models are used to track blizzards and predict how they will progress.

Dust storms

Dust storms are a more unusual form of severe weather. They are characterized as a strong windstorm that carries sand or dust particles. These storms can be particularly damaging to the agriculture industry, ruining crops for farmers.

Hailstorms 101

Hailstorms are characterized by balls of ice falling from the sky. These are generally formed in a thunderstorm and can damage windows, cars and other structures.

How does hail form?

Hailstorms form in cumulonimbus clouds, which are large mushroom-shaped clouds that are characteristic of a severe thunderstorm. Strong upward currents (also known as updrafts) must accompany these clouds, bringing water droplets up through the atmosphere. These droplets become ice, resulting in hail.

Don’t let a severe storm catch you off guard. Leverage our solutions and tools when violent weather approaches.

Advanced warning. Actionable information. Proactive alerting.

Severe storms—no matter the form they take—can develop quickly, change rapidly, and pack a punch. Heavy rains, wind gusts, lightning, hail (or any combination of elements) can put a field crew in danger and disrupt regular business operations.

The most accurate and timely information on these highly localized weather events needs to be communicated quickly. Whether it’s alerting field workers of lightning in their area, rerouting a flight or informing the public of storm details across multiple channels, businesses need specialized weather forecasting technology.

Broadcast media storm solutions

When a storm is in a local station’s coverage area, the latest severe weather information needs to be communicated across channels. People have always counted on their local TV station to provide severe storm information, but now broadcasters have to reach their audience on mobile apps and alerts, web and social media. The Max Ecosystem is designed with efficiency in mind and allows presenters to disperse information across multiple channels in just a few clicks—a critical need when a severe storm is approaching.

Additionally, by leveraging augmented reality solutions from The Weather Company, your team can better showcase the effects of violent weather to help your viewers visualize the impacts.

Frequently asked questions about severe weather

What causes severe weather?

Severe weather is caused by changes in the atmosphere in relation to temperature, wind or air pressure. These changes can result in tornadoes, blizzards, floods and ice storms.

What is the difference between severe weather and extreme weather?

While extreme weather and severe weather may sound like the same thing, they’re a bit different. Extreme weather is essentially any type of weather that is out of the norm for a particular area. Meteorologists will typically look to past historical weather data of that region to see whether or not the forecast falls within the range of what is considered normal.

How many types of extreme weather are there?

There are several types of extreme weather. These include:

  • Tornadoes
  • Hurricanes
  • Blizzards
  • Hail storms
  • Floods
  • Ice storms

What is the most dangerous kind of severe weather?

All severe weather can be dangerous. However, certain weather patterns have resulted in more lost property and lives than others. The largest number of deaths from US weather-related events are due to summer heat according to a 30-year average (1988 – 2017) from NOAA.* Additionally, over the last several years,* hurricanes Harvey, Maria and Irma, alongside the California wildfires, have had the most deadly outcomes.

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*Links resides outside of