How can we determine how far away lightning is? Make your own lightning Because of the vast differences in the speed of light and the speed of sound, the flash of lightning precedes the rumble of thunder. It takes sound… More
A radar unit consists of a transmitter and a receiver. The transmitter emits pulses of microwaves, a type of radio waves, outward in a circular pattern. Precipitation scatters these microwaves, sending some energy back to the transmitter, where it is detected by the radar’s receiver. The intensity of this received signal, called the radar echo, indicates the intensity of the precipitation. Measuring the time it takes for the radio wave to leave the radar and return tells us how distant the storm is. The direction the radar is pointing locates the storm. More
What are the different types of thunderstorms? A supercell thunderstorm over Chaparral, N.M., photographed by Greg Lundeen for NOAA Thunderstorms can be classified by severity or structure. For example, the National Weather Service defines a severe thunderstorm as one that… More
Wisconsin gets hit by lightning about 300,000 times a year; most of that during the spring and summer. That’s about five flashes for each square mile in the state. For about 20 years, the continental states have had a national lightning detection network. The network indicates that there are about 25 million cloud-to-ground lightning strikes a year. More
The probability of precipitation (fondly known as PoP) has been part of weather forecasts since the late 1960s, and is the only forecast element that includes a probability. Unfortunately, there is confusion about the exact meaning of a “60 percent chance of precipitation.” More
While some cartoons and some science diagrams draw raindrops in that shape, raindrops are neither tear-shaped nor spherical. Due to the interaction of cohesion, surface tension, air resistance and gravity, large raindrops are shaped more like the top half of a hamburger bun.
Did a volcanic eruption in Alaska impact weather in the Midwest? Mt. Redoubt, May 8, 2009 The eruption of Mt. Redoubt in Alaska in April, 2009 did not impact weather in the Midwest. Moderate eruptions can lead to cooler temperatures… More
When light beams interact with particles suspended in air, the energy can be absorbed or scattered. Scattering causes the light path to change direction. The amount of scattering is a function of the size of the particle relative to the wavelength of the light falling on it. More