Shop Windows to the Universe

With Explore the Planets, investigate the planets, their moons, and understand the processes that shape them. By G. Jeffrey Taylor, Ph.D. See our DVD collection.
Weather map showing a stationary front
Windows to the Universe image by Lisa Gardiner

Stationary Fronts

A stationary front forms when a cold front or warm front stops moving. This happens when two masses of air are pushing against each other but neither is powerful enough to move the other. Winds blowing parallel to the front instead of perpendicular can help it stay in place.

A stationary front may stay put for days.  If the wind direction changes the front will start moving again, becoming either a cold or warm front. Or the front may break apart.

Because a stationary front marks the boundary between two air masses, there are often differences in air temperature and wind on opposite sides of it. The weather is often cloudy along a stationary front and rain or snow often falls, especially if the front is in an area of low atmospheric pressure.

On a weather map, a stationary front is shown as alternating red semicircles and blue triangles like in the map at the left. The blue triangles point in one direction and the red semicircles point in the opposite direction. 

Last modified August 12, 2009 by Lisa Gardiner.

Shop Windows to the Universe Science Store!

Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store.

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Weather Fronts

When a front passes over an area, it means a change in the weather. Many fronts cause weather events such as rain, thunderstorms, gusty winds, and tornadoes. At a cold front passes there may there may...more

Wind

Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates different pressures in the atmosphere which creates the winds around the globe. Since the Earth spins,...more

Types of Thunderstorms

There are two main types of thunderstorms: ordinary and severe. Ordinary thunderstorms are the common summer storm. Ordinary thunderstorms last about one hour. The precipitation associated with them is...more

Supercell Thunderstorms and Squall Lines

A supercell thunderstorm is a huge rotating thunderstorm. It can last for several hours as a single storm. These storms are the most likely to produce long-lasting tornadoes and baseball-sized hail. Tornadoes...more

Thunder and Lightning

Lightning is the most spectacular element of a thunderstorm. In fact it is how thunderstorms got their name. Wait a minute, what does thunder have to do with lightning? Well, lightning causes thunder....more

Types of Lightning

Lightning can take place in several different areas of a thunderstorm. Most lightning (about 80%) occurs within a single cloud and is called cloud-to-cloud lightning. Most of the other 20% of lightning...more

Altocumulus

Altocumulus clouds are part of the Middle Cloud group (2000-7000m up). They are grayish-white with one part of the cloud darker than the other. Altocumulus clouds usually form in groups and are about...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA