Snow to Liquid Equivalent and Associated Forecasting Pitfalls

The snow-to-liquid equivalent is the amount of liquid precipitation that is produced after melting snow. The temperature profile of the troposphere and the surface temperature are important factors that determine this value. The “average” snow-to-liquid ratio is 10:1. This is saying that if 10 inches of snow fell and that snow was melted it would […]

Does a Warm Winter Mean the Summer Will be Hotter than Normal?

Introduction The title is a question that is frequently asked of meteorologists, especially in the wake of an abnormally warm or cool season; it is a topic of interest among atmospheric scientists and the general public alike.  In this article, we will attempt to answer this question using climatology, casting aside gut feelings and old […]

Television Meteorologists: A Look Behind the Scenes

This past summer of 2016, I took on a meteorology internship position at KWCH Eyewitness News, an affiliate of CBS, in Wichita, Kansas. Throughout my college education career at Penn State University, I have worked hard at rounding my experience throughout the weather enterprise in as many ways as possible. And, while my ultimate goal is […]

Undular Bores (Atmospheric Gravity Waves)

I captured spectacular gravity waves on radar this morning. Also known as undular bores, these are waves in Earth’s atmosphere that often show up quite well on satellite and radar imagery. They are notorious for creating wave-like clouds, which clearly propagate as waves when viewed in rapid time-lapse photography.  Low-level atmospheric stability is implicated in […]

Heat Index Calculator & Charts

The heat index is an estimate of how hot the air “feels” to the human body and provides a relative indication of potential health risks. Among others, the two primary factors in the heat index equations are temperature and water vapor (i.e., moisture/humidity). Humidity affects the efficacy of perspiration to evaporatively cool the skin. When […]

Dry line convergence & thunderstorm squall line formation

This phenomenon is NOT unusual, but it doesn’t always happen.  Today, the dry line and the resulting squall-line were perfectly aligned.  The data presented a teaching moment that I couldn’t pass up.  At the end of the animation, I zoom in so you can see the wind barbs pointing toward the dry line. The air […]

A few thoughts on forecast techniques & forecast variance

Friday 2/12… For the sake of conversation, I wanted to share some thoughts about forecast variance (i.e., the tendency for forecasts to vary from one meteorologist to another), forecast advancements, and forecast techniques. It goes without saying that atmospheric prediction is *extremely* difficult and time consuming. During an active pattern, a forecast for a 36-hour […]

What is virga? There’s rain on radar, but it’s not raining!

The fluid dynamics associated with atmospheric disturbances cause the downstream air (ahead of the disturbance, before it arrives at a location) to rise, and the upstream air (behind the disturbance, i.e., after the disturbance has passed).  If there is sufficient moisture in the area of rising air, clouds and precipitation may form.  Necessary and sufficient […]

What is thunder? How hot is lightning?

Imagine yourself as a cloud, happily floating over the surface of the Earth without a care in the world. As you drift across the sky, the millions of tiny water droplets and ice crystals that you are composed of brush against each other, causing a buildup of electric charges in your cloud body. The negative […]

Atlanta’s Top 20 Snowstorms & Temperature Trends

Atlanta’s biggest snowfall events of all time are listed in the table below.  The most snow ever recorded on a single day in Atlanta was on January 23, 1940 when 8.3 inches fell. The top 10 snowstorms in Atlanta have a median accumulation of 4.2 inches.  View the full list We often hear the cliche: […]

Watch a Full Year of Changing Seasons from Space

I love this animation.  After spending years trying to explain these concepts, along comes high-resolution satellite images sewn together from a Lagrangian perspective to create a fast animation that actually shows the seasons changing as Earth tilts on its axis from equinox to solistice to equinox and so on. Credit: Simon Proud, researcher in the […]

What is the water cycle and can the cycle be disrupted?

A follower asked, “if the water cycle is real, how can there be water shortages?” In light of the recent drought in Texas, which ultimately ended with the historic rainfall during the month of May 2015, and the ongoing devastating drought in California, I thought I would make this brief post. What is the Water […]

What is the Weather-Ready Nation Initiative?

The United States is also home to the most frequent occurrence and the largest variety of extreme weather events of any other country in the world.  These events include, but are not limited to, extreme heat/cold, snowstorms, tropical storms and hurricanes, droughts, areal and flash floods, hail storms, and tornadoes.  While none of this is […]

What is Cold Air Damming (the Wedge)?

Cold-air damming (CAD), often called “the wedge” in the Southeast, is an interesting meteorological feature that can result in tricky forecasts for meteorologists. Topography plays a major role in CAD events, and you need a mountainous range for this feature to develop. While CAD can occur in the Rockies, it is predominant east of the […]

Weather Myths: Too Warm for the Snow to Stick?

Before I begin this piece, I want to present a challenge.  The following chart shows the actual high and low temperatures for a full month at a location in the United States. *A condensed version of this writeup was also featured in the Douglas County Sentinel. Challenge: Can you spot the day with a historic […]

A Brief History of Weather Forecasting

The Weather Bureau, now known as the National Weather Service, was established on February 9, 1870 by the 41st United States Congress and signed by President Ulysses S. Grant.  On March 29, 1870, the new weather forecasting service was officially assigned to the U.S. Army Signal Service within the Department of War and given the […]

Lake effect snow formation illustration

Lake-Effect Snow: The Physics of Colossal Snow

One of the most awe-inspiring forces of nature is lake-effect snow. The amount of latent energy required to produce the lake-effect convection is astounding, and in some situations, snowfall rates can reach as high as 5 to 6 inches per hour.  In this article, we discuss the atmospheric physics, dynamics, and thermodynamics responsible for the […]