What is the cause of strong winds?

What is the cause of strong winds?

What is the cause of strong winds? Photo: wwwuppertal The wind is simply air in motion, flowing from high atmospheric pressures to low pressures. Moving anything requires a force. Strong winds are due to a strong pressure gradient force. A… More »

Sun pillar

Sun pillar

Sun pillar Sun pillar at sunrise by CaptPiper The other morning, I saw a column of light above the rising sun — what was that? A rising, or setting, sun behind high clouds will sometimes project a vertical shaft of… More »

What is sleet?

What is sleet?

Sleet is translucent balls of ice that are frozen raindrops. The most common forms of precipitation are rain, snow, freezing rain, and sleet. In Wisconsin, precipitation usually begins as ice particles in a cloud. The temperature conditions below the cloud base determine if the precipitation ends up as rain, snow, freezing rain, and sleet. More »

Where does the water come from in Midwestern snow storms?

Where does the water come from in Midwestern snow storms?

Where does the water come from in Midwestern snow storms? ENLARGE Photo: NOAA/NASA GOES Project Water can travel a long way to dump onto the Midwest as snow. This picture shows the storm system that cause the massive February 2011… More »

What are the northern lights?

What are the northern lights?

What are the northern lights? Aurora Borealis over Iceland, by Moyan Brenn The northern lights, also called aurora borealis, are an evening light show seen as a diffuse glow or as overlapping curtains of greenish-white and sometimes red light. Auroras… More »

Watch for steam devils in late November/early December

Watch for steam devils in late November/early December

Watch for steam devils in late November/early December Steam Devils in Wisconsin One of the many advantages of living near large lakes in temperate climates is the steam fog that shrouds them in fall and early winter. Fog is essentially… More »

When does winter really start in Wisconsin?

When does winter really start in Wisconsin?

When does winter really start in Wisconsin? State outline barely visible under snowcover (click image to enlarge), this is Winter in Wisconsin. Photo: MODIS Image Gallery by Liam Gumley, SSEC (Space Science and Engineering Center, UW, Madison). The beginning of… More »

How does frost form?

How does frost form?

How does frost form? Heavy frost on Burr Oak tree in Wisconsin Frost on objects is just water vapor in the air that has condensed as ice onto a surface. Frost forms on objects close to the ground, such as… More »

Why does El Nino often lead to a warmer winter in Madison?

Why does El Nino often lead to a warmer winter in Madison?

Why does El Niño often lead to a warmer winter in Madison? Image: NASA Forecasts of a relatively mild winter are being tied to a phenomenon called “El Niño” in the tropical Pacific Ocean. El Niño is so often invoked… More »

Is global warming real?

Is global warming real?

Is global warming real? Image: NASA Over the past two decades, the global average surface temperature has increased noticeably. This observed warming trend indicates a significant global change and is consistent with other observed changes on our planet: There is… More »

How long have satellites been used to study Earth’s weather?

How long have satellites been used to study Earth’s weather?

How long have satellites been used to study Earth’s weather? NASA image of Explorer VII satellite, 1964 The first successful meteorological experiment conducted from a satellite was launched on Explorer VII on October 13, 1959, just over 50 years ago.… More »

What is the jet stream?

What is the jet stream?

What is the jet stream? Photo: NOAA The jet stream is a narrow current of strong wind that blows through the upper regions of the troposphere, about seven miles above ground. The jet stream generally moves from west to east,… More »

How accurate are weather forecasts?

How accurate are weather forecasts?

How accurate are weather forecasts? Image: NOAA In general, weather forecasts are getting better, due to improvements in computer models, observations and our understanding of atmospheric. Accuracy depends on the purpose of the forecast and how far out it extends.… More »