Ten years ago today on the evening of May 4, 2007, the small town of Greensburg, Kansas, was nearly destroyed by a 1.7 mile wide EF-5 tornado, with a maximum wind speed of 205mph. Damage surveys concluded that about 95% of the city was destroyed, with EF-5 damage observed through the heart of Greensburg. The tornado tracked for … Read more
Global Wind 7-Day Satellite Loop Note: The purpose of this post is to share advanced forecasting techniques, not present formal research at this time. Example Case: April 17-18, 2016 Heavy Rain Event in North Texas ◙ I wanted to show some of the 48-hour rainfall amounts as of 7:00 am CDT April 18, 2016 (officially … Read more
During my 2016-17 winter break, I had the opportunity to work at the National Weather Service field office in Wichita, Kansas. Working with Chris Robbins, M.S. here at iWeatherNet had already shape much of my knowledge of the National Weather Service, since he worked for 15 years within the agency, including NOAA’s National Severe Storms … Read more
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 … Read more
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 … Read more
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 in Atlanta, Georgia. *A condensed version of this writeup was also featured in the Douglas County Sentinel. Challenge: Can you spot the day with a historic snowstorm? During this particular … Read more
A Few Interesting Facts and Myths About Daylight Saving Time 1. Terminology: Daylight saving time, not “savings”. 2. Bottling daylight most of the year. In the United States, we spend about 65% of the year (~238 days) in daylight saving time. 3. Two states do not observe DST: Hawaii and Arizona, except for the Navajo … Read more
The autumnal equinox occurs Wednesday morning at 3:20 am CDT, but the days and nights are not considered equal until Saturday, September 26th. This is because of the atmospheric refraction of sunlight. When a wave encounters a medium whose density differs from that through which the wave has been propagating, conservation of momentum and energy … Read more
Definition of Heat Index: 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 … Read more
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: … Read more
The evolution of broadcast meteorology goes hand in hand with scientific advances and the method that it is communicated to the consumer. Timeline of broadcast meteorology (1915-1982) The evolution of broadcast meteorology has worked hand in hand with advances in technology. This is true both with the scientific advances of meteorology itself, and the way that … Read more
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 … Read more
The National Weather Service’s Weather Surveillance Radar-1988 Doppler (WSR-88D) network across the United States consists of 155 Doppler radar sites operated by the National Oceanic and Atmospheric Administration (NOAA). In 2013, the entire WSR-88D network was upgraded to dual-polarization capabilities, meaning that the Doppler radar can emit pulses in both the horizontal and vertical plane. … Read more
A blocking weather pattern has encompassed much of the nation throughout the summer. A persistent area of high pressure and large-scale, high-amplitude ridging over the western half of the country has resulted in hot temperatures and extremely low atmospheric moisture content. These are the conditions necessary for the development of wildfires. Last week, NOAA’s Geostationary … Read more
Strong vertical wind shear is important for the development of severe convective storms including the type of thunderstorm, its orientation, and its life span. Wind shear can influence storms in several ways, including speed shear and directional shear. Speed shear is a change in the wind speed with respect to height, while directional shear is the … Read more
Introduction This informative forecast writing will focus on the weather forecasting tools and concepts that are used to predict winter weather events. There are various types of winter weather events that are analyzed and forecasted including mid-latitude cyclones, ice storms, lake-effect snows and sleet storms. Each of these will be discussed separately. In addition, bust … Read more
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 … Read more
The atmosphere can display phenomenal optical features through the bending of light. You may have looked up at the sky on a day with high-level clouds, e.g. cirrus clouds, which are composed of ice crystals. These hexagonal ice crystals act as prisms, and when a photon (a particle of light) passes through the ice crystal, … Read more
If you are searching for diverse weather or extreme temperatures and precipitation, the U.S. is certainly one of the places to be. Have you ever wondered what U.S. city is the coldest or the warmest? What city experiences the most rainfall or the most thunderstorms? I thought that it would be interesting to come up with … Read more
In an earlier article, we discussed the dynamics and thermodynamics of lake effect snow. In this post, we discuss the meteorological differences between single-band and multiple-band lake-effect snow events. Keep in mind that all lake-effect snow events are fueled by moisture and latent heat flux from the relatively warm lake water; these fluxes are already … Read more
Atmospheric gravity waves, known as undular bores, 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 the formation of undular bores. Large static stability … Read more
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 … Read more
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) to sink. If there is sufficient moisture in the area of rising air, clouds and precipitation may form. Necessary … Read more
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 … Read more
Snow is a precipitation type that results from the build-up of ice deposition upon condensation nuclei. The snowflake size is amplified as ice crystals join together as the crystals move in the wind. A common theme in ice crystal development is the 6-sized structure of the ice crystals. The chemical bonding of ice molecules produces … Read more
From elementary school through high school, I always looked forward to the month of March. But not for reasons that you might think. It was the month that I competed in science fairs. During those years, I had my share of successes and disappointments, but the benefits of my participation continue to this day. My experience with … Read more
Section 1: Is it Going to be a Big Deal? One of the more difficult forecasts to make is the winter precipitation forecast. The complexity is with determining precipitation type, areal coverage, and whether any winter precipitation will accumulate at the ground surface in the first place. The public is very sensitive to winter forecasts … Read more
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 … Read more
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 … Read more
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 … Read more