How can we determine how far away lightning is?

How can we determine how far away lightning is?

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 »

What is space weather?

What is space weather?

What is space weather? Space weather describes the conditions in space that affect Earth and its technological systems. Space weather storms originate from the sun and occur in space near Earth or in the atmosphere. Space weather, like weather here… More »

What are growing degree days?

What are growing degree days?

What are growing degree days? The Growing Degree Day, or GDD, is a heat index that can be used to predict when a crop will reach maturity. Each day’s GDD is calculated by subtracting a reference temperature, which varies with… More »

What is the dewpoint temperature?

What is the dewpoint temperature?

What is the dewpoint temperature? Dew on evergreens, by Michael Theberge at NOAA Think of a morning when you walked on a grass lawn or through a field. Did your shoes get wet? If yes, that is because the grass… More »

What is a landspout tornado?

What is a landspout tornado?

What is a landspout tornado? Landspout tornado over Hale County in Texas (NOAA). “Landspout” is slang for a tornado that, unlike most tornadoes, is not associated with the mesocyclone of a thunderstorm. The name reflects the fact that these tornadoes… More »

How does weather radar work?

How does weather radar work?

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?

What are the different types of thunderstorms?

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 »

Why are clouds white?

Why are clouds white?

Why are clouds white? Photograph of Cumulus clouds in fair weather taken by Michael Jastremsk Clouds are made of water and clean water is clear. So why are clouds white? Because clouds are made of billions of small water droplets… More »

How many lightning bolts hit Wisconsin each year?

How many lightning bolts hit Wisconsin each year?

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 »

What does a 60 percent chance of precipitation mean?

What does a 60 percent chance of precipitation mean?

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 »

Are raindrops tear-shaped?

Are raindrops tear-shaped?

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.
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How much water is in the atmosphere?

How much water is in the atmosphere?

How much water is in the atmosphere? Water is an exceptionally interesting chemical with many important implications for life on Earth and the circulation of the atmosphere. It is the only chemical that naturally exists in all three phases (solid,… More »

Did a volcanic eruption in Alaska impact weather in the Midwest?

Did a volcanic eruption in Alaska impact weather in the Midwest?

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 »

Why is the sky blue?

Why is the sky blue?

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 »

Where does the dew on blades of grass come from?

Where does the dew on blades of grass come from?

Where does the dew on blades of grass come from? As fall begins, we have lots of mornings with dew on the grass. To explain this, we start with the fact that air contains water in the gas phase, called… More »