If you’ve been in Dallas for any decent amount of time, then you’ve undoubtedly experienced some of the city’s infamous spring storms. Steadily-darkening skies lead to cracks of lightning and bone-trembling rolls of thunder and deluges of sharp rain.
Then, almost as if Mother Nature suddenly tired of the game, it’s all over. The storm moves on and the sun starts to shine, then it starts all over again in a day or two.
So, why does Dallas get so many thunderstorms? And why do these thunderstorms only pop up around April and May?
The answer lies in a combination of warm air, cold air, moisture and Thor, the God of Thunder. Well, it lies in three of those things, at least. We’ll attempt to explain the ancient process of weather in relatively simple terms so that you can finally put an end to that pesky weather small talk. No, person-I-don’t-know-in-the-elevator, these thunderstorms aren’t strange, actually. Here’s why.
Why does Dallas get so many thunderstorms?
The key to understanding what makes Dallas a hotspot for stormy weather is understanding how these storms form in the first place. That will make a lot of the seemingly random weather seem a little less strange and a little more predictable.
How do thunderstorms form?
Thunderstorms require three things: moisture, lift and unstable air.
This usually comes from oceans. If the ocean has a warm current, then the air will absorb more moisture than air around a colder current will. Moisture is what makes clouds, so therefore more moisture means more clouds and more rain, which leads to more thunderstorms.
Unstable air is created when there is hot and cold air in the same place, but at different levels. Hot air is closer to the ground as the sun warms the Earth, and cold air is higher because of the high winds and cold fronts.
Lift is what happens when the hot air begins to rise toward the colder air. This can come by hot air being forced up a hillside, the sun quickly heating up air on the ground or even the appearance of a weather front, such as a hot or cold front.
Hot air rises. That’s its nature. When this warm, moist air begins to rise, it meets the cold dry air that’s hanging out at higher elevations. As the moisture in the warm air interacts with colder temperatures, it turns into water droplets, which can turn into hail, snow or rain. The cloud is formed by the hot air rising then cooling, sinking then warming, then rising again over and over again. This circular process of heating and cooling is called convection, and the air trapped in this circuit creates a convection cell. These cells are what form clouds.
If there is a lot of warm air and moisture in this convection cell, then the clouds can become massive centers of strong circulating winds. These strong winds are what can lead to tornadoes, hurricanes, wind storms, hail storms and other similar weather events.
Lightning and thunder are created by water molecules in these clouds crashing into each other as they plummet and rise through the cloud. The ice heading down smacks into the water heading up, stripping away electrons from each other. The negatively charged water droplets keep falling while the positively charged droplets continue to rise. What we’re left with is a cloud that’s about as unstable as a one-legged stool; a huge negative charge on the bottom, and a huge positive charge on top.
Lightning forms when the negative electrical charge attracts the nearest positive charge, creating a path where the built up charge is released in a powerful display. Most of the time, this path connects between charges in the cloud itself, while sometimes it’s between the cloud and the ground. Thunder is the sound that occurs as a result of that charge releasing.
And Voila! That’s lightning and thunder!
Why Dallas has so many thunderstorms in April and May
So why the weather lesson? Apart from reminding us all how much we definitely don't remember from high school environmental science class, it explains exactly why Dallas has such a hectic thunderstorm season for the same two months every year!
Thunderstorms need moisture, unstable air and lift, right? Well, all these ingredients are present over Dallas exactly around April and May. The jet stream, a strong band of high-altitude wind that circles the planet, blows cold, dry air over the city during the spring season. At the same time, warm moist air is blown up from the ocean as the Gulf of Mexico warms in the springtime sun. This creates the perfect storm… literally. That warm moist air from the ocean begins to interact with the cooler, drier air from the jet stream, creating the powerful thunderstorms that we are all familiar with.
As the summer creeps closer, that powerful jet stream moves further north, and there is more warm air than cold air present in the area. The weather begins to dry out a little more, too, meaning that there is less moisture in the air.
Of course, this doesn’t mean that thunderstorms happen exclusively in April and May! The “ingredients” of a thunderstorm still exist in the air, but on a much smaller scale. The day-to-day weather patterns could introduce more moisture, more hot air or more wind to create another storm, but the large-scale weather patterns that govern the changing of the seasons are not quite as strong, so neither are the storms.
Next time those spring storms roll over our Dallas apartments, blanketing the city in booming thunder and that heavy cloud cover, you will know exactly how and why these famous Texas thunderstorms show up every single year without fail. And, if we dare to predict the weather so far in advance, they will probably do the exact same thing next year, too.
Featured photo courtesy Pixabay/jplenio