We’ve all been there. You’re heading out for a peaceful walk or to hang out the wet washing when the sky opens up and a downpour starts.
Or perhaps you’re out camping or hiking when the clouds part and the sun shines brightly. Either way, we know what it feels like when the weather changes quickly.
But why do things happen so fast? How come it takes just seconds for a storm front to move across town? And how can anyone predict this sort of weather?
There are many different factors that contribute to the weather. Including air pressure, temperature, humidity, wind speed, precipitation, cloud cover, and solar radiation.
And while scientists don’t always agree on what exactly causes certain types of storms, one thing is clear: the atmosphere is constantly changing.
So let’s take a look at some main reasons why the weather changes so quickly, and see if we can figure out why it happens the way it does.
What Causes Weather To Change
Changes in weather are primarily the product of a change in:
- Air pressure
These three variables interact with each other to form a complex set of physical processes that ultimately determine what happens next.
When any of these three variables experiences a substantial change, it leads to a complete change in the weather. However, there are many other factors that affect the overall weather pattern.
In fact, there are several different types of weather systems that exist in our atmosphere. Some of these include cyclones, tornadoes, thunderstorms, rain clouds, snow clouds, dust storms, fog, and hurricanes (also see ‘Hurricanes: All You Need To Know‘).
For example, when a storm cell forms over a region, it produces a large amount of wind shear across the surface of the earth.
This causes the surrounding air to become unstable, resulting in turbulence that eventually creates a vortex within the storm cell.
As the air inside the storm becomes cooler, it begins to condense. Once the air mass reaches saturation, it releases moisture into the air, causing a storm cloud to develop.
The interaction between these three main components of the atmosphere — temperature, air pressure, and humidity — determines whether we see clear skies or cloudy skies.
If the temperature rises above freezing, the water vapor in the air begins to evaporate.
As the air cools down, the relative humidity increases. This makes the air feel drier and colder, which encourages the evaporation of additional water molecules.
Air pressure is measured in millibars (also see ‘How Does A Barometer Work, And What Is It?‘). If the air pressure decreases, the air becomes less dense. This reduces the ability of water molecules to hold onto one another, which allows the air to expand.
As the air expands, it cools off even further. This process continues until the air temperature falls below freezing. At which point the water vapor in the atmosphere freezes out.
Humidity plays a key role in determining how warm or cold the air feels. Humidity refers to the percentage of water vapor in the air.
A humid environment is one where the air contains a lot of water vapor. An extremely dry environment is one where very little water vapor exists.
Why Does The Weather Change So Quickly
Weather is the state of the atmospheric conditions at any given time. Although daily changes in weather are caused by wind and storms, the seasonal variations we experience are due to the earth rotating around the sun (also see ‘Why Does Earth Have Seasons?‘).
This causes the difference in the amount of solar radiation received by different parts of the Earth.
Because the Earth is round, the Sun’s rays do not fall equally on the land and ocean.
Differences in these temperatures cause a constant motion of air over the continents and oceans. Creating great swirling currents that distribute the heat energy of the sun throughout the world.
When the air in one area is warmer than the surrounding areas it becomes less dense and rises, pulling in colder, more dense air from beneath it.
In contrast, where there is cool, dry air sinking into a warm layer of air it creates an upward rush of air bringing in more air from beneath it.
The result of this process is a continual change in the weather patterns that affect our lives. And often sudden changes that are hard to predict.
There are three main types of coastlines: those that run parallel to the shoreline, those that follow the contours of the land, and those that run along the edge of the water.
Each type of coastline experiences a unique set of weather patterns because each type of coastline is exposed to a particular kind of wind.
The coastlines of North America are home to some of the most extreme climates in the world. From Alaska to Florida, the coasts are subject to frequent storms, high tides, and powerful waves.
They also receive large amounts of precipitation because of the warm water currents coming off the Gulf of Mexico.
Coastal areas are often hit harder by hurricanes than inland regions. Hurricanes form when the wind speed reaches 74 mph or greater, and the amount of moisture in the atmosphere increases.
As the storm approaches land, it picks up energy from the mountains and rivers along the way. If the storm hits land near a coastline, it gains additional power from the warm waters of the Gulf Stream.
As a result, hurricane intensity increases rapidly over open bodies of water such as oceans and lakes.
Inland seas like the Great Lakes have less impact on the development of tropical cyclones, and therefore, do not see nearly as much damage as coastal areas.
Topography is one of the most important factors in determining how weather moves across a region. A mountain range can act as a barrier, slowing down the movement of air masses, while a plain allows for an easier flow of air currents.
This can lead to very different weather patterns depending on where exactly you live. In some cases, mountains can actually cause weather systems to move faster and become stronger.
The role of topography in forming weather is often underestimated. But it can be responsible for the absence (or presence) of certain weather conditions as well as influence the strength and duration of a weather pattern.
When it comes to rapidly changing, unpredictable weather, the importance of topography becomes even greater.
Where a mountainous terrain may slow the passage of air masses, a flat terrain allows for an easy flow of air currents. Because of this, temperatures can change quickly and easily over short distances.
And since the air is moving so much faster, there is less time for clouds to form. If you live in such a place, you may find yourself facing a completely different set of conditions by the end of a given day.
How Weather Is Predicted
Weather forecasts attempt to predict future weather conditions. These forecasts are called long-range forecasts because they cover periods of up to a week ahead.
Short-term forecasts, such as those you might see on TV or online, are generally shorter than a week.
Short-term forecasts are often used for things like planning trips, where knowing what the weather will be like on a particular date is important.
However, there are many factors that affect short-term forecasts, making it difficult to know exactly how accurate they are.
Long-range forecasts are useful for people living in areas prone to severe weather events. For example, a farmer could use long-range forecasts to plan planting times.
If they know the weather is likely to be dry over the next few weeks, they can plant crops accordingly.
The process of creating long-range forecasts begins with observing the atmosphere.
Meteorologists record daily observations of the atmosphere, including temperature, atmospheric pressure, winds, humidity, and rainfall.
They combine these observations with satellite images showing cloud movements.
From here, researchers develop models that describe the relationship between the observed data and the weather patterns. These models are then tested against historical data.
These measurements are taken every hour throughout the day and night.
Using this information, researchers can make predictions about the weather over the following 24 hours.
Erratic Weather Predictions
It is possible to predict erratic weather but there are many variables that affect how accurate a forecast is. One important factor is the speed at which data is collected and processed.
For example, it takes longer to collect data about the atmosphere and predict what might happen next. As a result, there is often a lag between when a prediction is made and when it becomes reality.
Another factor is the type of model used to make a forecast. Models that use historical data tend to work better because they take into account trends and patterns that already exist.
However, some types of models rely heavily on current conditions, making them less useful for predicting the future.
Weather forecasters must balance the benefits of being able to predict something with the risks of getting it wrong. Sometimes, inaccurate predictions can cause people to panic unnecessarily.
In addition, sometimes incorrect information can lead to costly mistakes. Such as closing down businesses or canceling flights.
Climate Change Impact On Weather
Climate change is affecting how we experience weather. This includes everything from the way we feel about it, to what happens when it hits us.
In fact, climate change makes extreme weather – such as hurricanes, floods, and drought – much worse.
We know that the average global surface temperature has increased by around 0.8°C since the end of the Little Ice Age. But a warmer atmosphere holds more water vapor, which leads to heavier rainfalls.
And because the oceans absorb more energy, they release less heat into the air. This means that there is more warming in the upper layers of the ocean, and less cooling in the lower levels.
As a result, sea level rise is accelerating and storms are intensifying.
The impact of climate change varies greatly across the globe. Some areas will see no changes, while others will suffer dramatic impacts.
For example, some regions will be hit harder by heavy rains, while others will see fewer and shorter droughts.
So there we have it, information on how and why the weather changes so quickly.
Weather forecasting is an essential part of our lives. We need to understand how it works so we can plan ahead and prepare for any potential problems.
The science behind weather forecasting is constantly evolving. And new technologies allow scientists to gather more detailed data than ever before. What a fascinating time to be alive!