Weather and Wellness Wednesdays by K. Esters: June 2025

This past Friday marked the first official day of summer. I actually love the heat and humidity of Gulf Coast summers (I know...I’m an anomaly). I am always happy on a bright, sunny day, and I find comfort in the stillness of warm, humid summer evenings. But I am well aware that summer brings a mix of joys and hazards.

There are some summer health risks that we hear about often:

Powerful UV rays can cause sunburns and increase the risk of skin cancer.
Exposure to heat and humidity can lead to heat-related illnesses.
Ground-level ozone caused by the combination of sunshine and pollutants such as car exhaust can be harmful to those with respiratory illnesses.

However, there is one summer hazard that I feel is often overlooked, but it is so fascinating that I’ve given it a name: The Rush-Hour Rumbler.

What Is a Rush-Hour Rumbler?

“Rush-Hour Rumbler” is my nickname for the quickly forming isolated thunderstorms that occur like clockwork between 3pm and 6pm on hot summer days. Unfortunately, these storms form right as people are leaving work, picking up kids from school, or heading out to run errands. They are typically referred to as 'pop-up thunderstorms' or 'popcorn storms' due to how quickly they form and how randomly they seem to appear. But I think that the term “Rush Hour Rumbler” captures both the timing and the impact of these storms (and be honest...who doesn’t like a little alliteration?)

You may be familiar with this weather pattern, especially if you live in the south or along the coast:

The day starts out clear, hot, and sunny.
By mid-afternoon, cotton-like cumulus clouds begin to gather in the sky and begin to grow tall.
By late afternoon, the blue skies have turned dark and ominous, and suddenly, there’s heavy rain, wind, and lightning.
After about a half hour of atmospheric chaos, the skies clear, and if you are lucky, you may catch a late evening rainbow!

Rush-Hour Rumblers are usually brief, but they can be intense, and can reach severe limits. They create a perfect recipe for hazardous travel because they occur at peak travel times.

What Are Some Sources For These Storms?

Daytime Heating (Convection): On summer afternoons, the sun heats the ground and the air above it. Warm, moist air rises and cools as it ascends, forming towering cumulonimbus clouds. If the atmosphere is unstable this convection leads to thunderstorms.

Sea-Breeze Convergence: In coastal areas, a sea breeze can push moist ocean air inland, where it collides with warmer air over land. This upward lift often sparks thunderstorms, especially in the late afternoon hours.

Outflow Boundaries: Thunderstorm outflow is cool air that spread down and out from a storm. An outflow boundary separates the thunderstorm-cooled air from the surrounding air. When these boundaries collide with warm surface air, or other outflow boundaries, they create lift which can result in new thunderstorms. (Weather Nerd Note: This process is very cool to watch on a radar loop!)

"Ring of Fire": During the summer, large areas of high pressure can form and result in extreme heat. This area is sometimes referred to as a "heat dome". Thunderstorms can form and rotate around the edges of the high pressure system where the air is unstable and uplifted.

Urban Heat Island Effects: Cities tend to be hotter than surrounding rural areas due to buildings, roads, and infrastructure absorbing and re-radiating heat. Some studies suggest this added heat and rising motion can trigger storms or intensify ones that move overhead.

These late morning cumulus clouds signal rising heat.
By late afternoon, they can develop into towering storms.

The Safety Hazards of Rush-Hour Rumblers

Let's look at why Rush-Hour Rumblers matter for public health and safety:

Hazardous Driving Conditions

Sudden downpours reduce visibility and create slick roads.

Storms during peak traffic times increase the risk of car accidents.

Strong Wind Gusts

Winds can down tree limbs or blow debris into roadways.

These obstructions are especially dangerous when visibility is already low due to heavy rain.

Lightning Strikes

Even short-lived storms can produce frequent lightning.

While it may be rare for vehicles to be struck by lightning, lightning risks are especially dangerous for people who are outdoors during the storm (parking lots, bus stops, etc.)

Flash Flooding

Rush-Hour Rumblers can drop several inches of rain in under an hour.

Urban drainage systems can be overwhelmed, leading to ponding or flooding, especially on low-lying roads and underpasses.

Flash flooding can result in car stalls, or even worse, the car could be swept into a larger body of water (stream, canal, lake, etc.)

Staying Safe during Rush-Hour Rumblers Season

Whether you're commuting from work, picking up kids, or enjoying outdoor recreation, here’s how to stay safe when Rush-Hour Rumblers arrive.

Know your routes: Avoid flood-prone areas and learn alternate routes.

Check the forecast: Use weather apps and radar to stay informed.

Wait it out in a safe space: If a storm approaches, stay put until it passes instead of heading to the car to try to “beat the rain.”

Remember: Never drive into floodwaters!

Just 6 inches can knock over an adult, and 12 inches can move a car.

Do you have Rush-Hour Rumblers in your area during the summer? Share your insights in the comments below!

Sources:

https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/

https://www.noaa.gov/jetstream/ocean/sea-breeze

https://www.theweatherprediction.com/habyhints/6/

https://www.sciencedirect.com/science/article/abs/pii/S135223109900374X

Image from the Cooperative Institute for Meteorological Satellite Studies

SALutations and welcome to a special Friday edition of the Weather & Wellness Wednesdays blog! I'll be transparent with you: I planned a blog post on an entirely different topic for this week. However, after seeing a somewhat dramatic headline by the Daily Mail, I decided to switch gears. So what was the headline that made me stop in my tracks?

Apocalyptic Aerial Hazard the Size of US Barrels Toward Florida Triggering Public Health Warnings

Yikes, that sounds like a description of a disaster movie! Fortunately, there is no need for anyone to rush into underground bunkers! What the Daily Mail is referring to is the transport of the Saharan Air Layer, an annual atmospheric occurrence that can pose some health issues, but can also be beneficial as well.
What's the deal with SAL?
The Saharan Air Layer (SAL) is a mass of very dry, dusty air that forms over Africa over the Sahara Desert. It can be up to 2.5 miles thick and is found in the lower atmosphere, about 1 mile above the surface. Beginning in late spring, the Saharan Air Layer, accompanied by large plumes of dust, is transported westward over the Atlantic Ocean due to easterly winds. Summer brings the peak of “SAL season” and these plumes can leave Africa every 3 to 5 days! This dusty air can travel thousands of miles and at times can reach the United States.
Is SAL good or bad? (Hint: It's complicated!)
Like many aspects of our atmosphere and environment, SAL can bring both benefits and challenges. Let's first explore some of the positives:
Tropical System Suppression
Remember I mentioned that the peak of the “SAL season” occurs in the summer? That means that SAL season coincides with the Atlantic Hurricane season. The presence of SAL can hinder the development of tropical storms and hurricanes.
Most of our weather happens in the troposphere, the lowest level of the atmosphere. In order for tropical storms and hurricanes to form (or maintain intensity), you need the atmosphere to be warm, moist, and unstable. In an unstable atmosphere, air temperature decreases with height. In unstable conditions, when an air parcel rises due to the heating of the surface of the earth, it will continue to rise easily because the parcel will remain warmer and less dense than the surrounding air. Due to the process of convection, this rising motion supports the development of thunderstorms and, eventually, tropical systems.
However, the presence of SAL can lead to a stable atmosphere by adding hot, dry air over the ocean and creating a temperature setup called an inversion. This is where the air temperature increases with height instead of decreasing. When a rising air parcel reaches this inversion, it may cool faster than the air around it, causing it to stop rising and eventually sink. This will stop the growth of thunderstorms and can prevent the formation of a tropical system (or weaken one that has already formed) .
Fertilization of the Land and Sea
The dust in the Saharan Air Layer is composed of elements such as iron, calcium, carbon, and aluminum. Phosphorus is also found in Saharan dust, and it plays an important role in the growth of plants. Phosphorus deposited by the dust can serve as an important fertilizer for the Amazon rainforest and replace nutrients that are lost there due to heavy rain.
The phosphorous in the dust also deposits over the ocean where it can help the growth of phytoplankton, or microscopic algae. Phytoplankton serve as a primary source of food for marine life and through photosynthesis, produces oxygen in our atmosphere.
Colorful Sunrises and Sunsets
Particles in the air can scatter incoming sunlight. The dust transported in the Saharan Air Layer can scatter the sunlight and result in stunning sunrises and sunsets with vibrant red and orange colors decorating the sky! I've found the SunsetWx website to be a helpful tool for predicting beautiful "SAL-induced" sunsets. Below is a sunset forecast from the Sunset Wx webpage. The warmer colors (yellow, orange, and red) indicate a higher likelihood of a vibrant sunset. Saharan dust is present in varying concentrations over Louisiana and Florida today, and those areas may have beautiful sunsets this evening!

Sunset WX forecast for the evening of June 6, 2025

While the Saharan Air Layer offers some notable benefits, it also can bring some potential hazards:

Decreases In Air Quality

Exposure to dust can cause or worsen health conditions for those who live with allergies, asthma, COPD, or other respiratory issues. Saharan dust is a type of particulate matter, which are small, solid particles found in air. This dust can be smaller than 10 micrometers (PM10), and particles this size can be inhaled deep into the lungs and result in respiratory symptoms such as coughing , wheezing, and shortness of breath. Research into Saharan dust effects on those living in the US is ongoing, but there are studies that have shown an association between SAL and COPD exacerbations.

Increases in Harmful Algal Blooms

The iron and phosphorous transported in Saharan dust over the ocean can serve as fertilizer for red tide or other harmful algal blooms. These blooms are toxic to sea life, humans, and pets. Red tide can harm sea life by reducing oxygen levels and causing mass die-offs of fish or other sea creatures. The algae also produce toxins that humans can be exposed to through direct contact with water, by inhalation, or through consumption of seafood. Symptoms from exposure to red tide include headaches, stomach pain, and irritated eyes. More serious symptoms can include seizures and liver failure.

Image of Red Tide near San Diego, California

Keeping Tabs on SAL

So now that we know more about the Saharan Air Layer, how can we track where it is and where it is headed?

Weather Broadcasts: In each of the "Weather and Wellness Wednesday" posts, I have emphasized the importance of paying attention to weather forecasts. I've been very impressed by how well broadcast meteorologists have been communicating the arrival of Saharan dust in their respective forecasts areas. Many news stations have their own proprietary "Saharan Dust Trackers" that show the movement and concentration of dust. Their grounded and informative forecasts are necessary to eliminate any fear caused by misleading and scary SAL- related headlines.

Article content — My Fox Hurricane: Saharan Air Layer Forecast for June 6, 2025

Air Quality Forecasts: Another way to keep track of Saharan Air Layer movement is through air quality forecasts. You can find air quality forecasts at airnow.gov or on your state air quality agency website (this is usually a state Department of Environmental Quality or Department of Health) Airnow.gov will display a color-coded graphic of the air quality index for your area and will provide a detailed forecast on the page as well.

Satellite Images: If you are a weather nerd like I am, you may want to find satellite images of SAL. The Cooperative Institute for Meteorological Satellite Studies /University of Wisconsin-Madison has a website dedicated to the Saharan Air Layer. There, you can find several SAL-related satellite products. In the image below downloaded from the website, you can see the the dry Saharan air as a murky brown color swirling through the Atlantic and the Gulf of Mexico.

Staying Healthy

You do not have to fear the arrival of the Saharan Air Layer in your area! However, if you are sensitive to dust and decreases in air quality, there are some steps you can take to ensure that exposure to the dusty air doesn't result in respiratory illness:

Keep an eye on air quality forecasts and reduce time outdoors, if necessary: If the Air Quality index suggests that conditions are gong to be unhealthy for sensitive individuals, you may consider reducing the time you spend outdoors.
Consider wearing a mask : If you must be outside for long periods of time, consider a wearing a good quality mask such as a KN95 to reduce exposure to the dusty particles.
Use an indoor air purifier: Dusty air can make its way indoors, so consider purchasing an air purifier to keep the air inside your living quarters as clean as possible.

If you are aware of any additional benefits or hazards of the Saharan Air Layer, please share your thoughts in the comment area!

Image Sources:

https://sunsetwx.com/sunset/sunset_ct.png?xx2lo9

https://www.noaa.gov/what-is-harmful-algal-bloom

https://www.myfoxhurricane.com/saharan_dust_car.html

https://www.airnow.gov/?city=Baton%20Rouge&state=LA&country=USA

https://tropic.ssec.wisc.edu/real-time/sal/salmain.php?&prod=airmass&time=

Article Sources:

https://www.aoml.noaa.gov/what-is-the-saharan-air-layer/

https://www.wunderground.com/hurricane/articles/saharan-dust-explainer

https://www.nationalgeographic.com/science/article/concerned-saharan-dust-plume-crucial-to-ecosystem

https://pmc.ncbi.nlm.nih.gov/articles/PMC11523266/