The negative values (down the left side of the radar graphic key) represent wind
speeds towards the radar and the positive values (down the right side of the key)
represent wind speeds away from the radar. Red next to blue would be an indication of
Although it is not possible to predict tornadoes as easily as it is to predict tomorrows
high and low, lives have been saved by Doppler radar, which can help in warning people of
severe storms. Most people have heard of Doppler radar, but not everyone knows what
Doppler radar really is. Doppler radar in scientific terms is radar that uses the Doppler
effect to measure velocity.
Doppler radar was first discovered by Christian Doppler using sound waves. Today Doppler
radar is used to detect storms and their intensity. Doppler radar works by sending out
radio waves from an antenna. These radio waves are reflected back to the antenna by
objects in the air. Through this process Doppler radar can detect precipitation in the
air. It even detects frequency differences based on whether an object is moving away from
the antenna or towards it. The frequency will be lower if the object is moving away from
the antenna and higher if the object is moving toward the antenna. After the antenna
detects an object it sends the information back to a computer that brings up the different
frequencies as different colors. The colors used represent speed and direction to the
user. Using this method meteorologists can tell a lot of things about the storms it
Two of the most important things that meteorologists can learn about storms
through Doppler radar are the intensity and location of storms. Using this important
information they are then equipped to send out warnings for specific areas. Doppler radar
is what aids meteorologists in sending out tornado warnings. If the Storm Prediction
Center issues a tornado watch it means that conditions are right for the development of
severe storms with the ability to produce tornadoes. When the National Weather Service has
issued a Doppler indicated tornado warning it means that Doppler radar has indicated a
tornado over that area. A Doppler radar indicated tornado has not necessarily touched down
on the ground, but is instead rotation that has been detected in the clouds. For this
reason when the national weather service sends out a tornado warning it is very important
to take the proper precautions because a tornado is very likely to set down at any moment
if it hasn't already.
Doppler radar can also tell meteorologists the direction that storms are heading.
This helps them know which areas to warn of the impending storm. For instance if there is
a tornado warning over Northern Weld County in Colorado and meteorologists see that the
storm is heading quickly southeast they know to warn the people in Morgan County of the
approaching storm and that it could produce a tornado. This also helps tornado chasers
know where to position themselves when plotting an intersect course with the storm.
Another thing Doppler radar tells meteorologists is the direction and speed of winds
inside of storm. This allows them to visibly see rotation in a storm, how intense the
rotation is and send out warnings accordingly.
Although Doppler radar cannot predict storms before they have formed, nor can Doppler
radar pinpoint perfectly where a Doppler tornado is, it has still helped save many lives.
Doppler radar helps the everyday person in many convenient ways. When you watch a weather
station the meteorologists are using Doppler radar, many weather web-sites feature maps of
Doppler radar with charts to help you know what kind of storms are headed your way.
Doppler radar enhances weather radio by giving the public quick warning. Because of this
very useful tool meteorologists are able to help people know when they should be keeping
their eye on the sky.
are the fastest winds recorded by Doppler radar of a tornado?