Wnem Radar (2024)

FAQs

How can you tell how fast a storm is moving on radar? ›

Velocity data is derived from the phase, or doppler shift of the returned energy. The radar's computers will calculate the shift and determine whether the precipitation is moving toward or away from the radar, and how fast, then apply a corresponding color to those directions and speeds.

Warm colors (red) / positive values indicate wind moving away from the radar (along a radial). Cool colors (green) / negative values indicate wind moving toward the radar. Purple indicates “range folding”— where the radar cannot determine the radial velocity. Velocity image of a large-scale weather system.

Black dots represent divergence centers. Arrow length is proportional to wind speed. Negative (positive) Doppler velocities represent flow toward (away from) the radar. (

On a weather radar map, a tornado is usually indicated by a smaller area of red surrounded by a larger area of green. However, modern radar systems can also indicate debris balls, a sign of a tornado on the ground.

Purples and blues indicate the strongest winds, while dark greens are lighter winds. The greyish shades in the middle of the spectrum indicate very light winds or none at all. Then the right side indicates echoes moving away from the radar.

Purple denotes range-folding (RF), which is when the return from a prior pulse is detected during the listening period for the current pulse, and the radar is unable to determine the wind's velocity. Other radar systems commonly use this color scheme, but some may use different colors.

A patch of dark red moving toward your location means there's a thunderstorm on the way. A line of heavy precipitation moving in unison is a sign of a squall line that could pack gusty winds.

Yellow and orange colors show moderate-to-heavy precipitation, while red is very heavy rainfall and pink and blue colors inside the red color represent hail of different sizes.

The WSR-88D is one of the most powerful and advanced Weather Surveillance Doppler Radar in the world. Since first being built and tested in 1988, it has been installed and used operationally at over 160 locations across the United States, including Alaska and Hawaii.

Red indicates the winds moving away from the radar whereas green displays the winds moving toward the radar. Brighter shades identify faster winds whereas darker shades show slower winds. Such maps typically indicate a tornado by a smaller area of red surrounded by a larger area of green.

Can radar detect speed while moving? ›

Moving radar allows an officer to clock vehicles while driving on patrol. It can clock oncoming vehicles and if it has dual antennas, a departing car can also be clocked from behind, after it's passed the rolling cruiser.

By convention, green colors indicate winds blowing toward the radar and velocity values are negative. Red colors indicate winds blowing away from the radar and velocity values are positive. This convention comes from the early days of Doppler radar when radars pointed vertically.

This often appears as a red area directly next to a green area as seen on the NWS image below. If the radar shows a strong area of rotation and a debris ball in the same area, it is a strong signature that there is a tornado occurring.