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National Weather Service  Radar

Doppler Radar Central Great Lakes Mosaic Loop

National Full-Res version (3400x1700 pixels - 220k) | Go to: National Mosaic

Regional Mosaic - Latest Image
Great Lakes Mosaic

Cleveland, OH radar
Cleveland, OH

click for Grafton TDWR radar

Grafton, OH

Terminal Doppler

Weather Radar

Nearby National Weather Service Radars

Chicago, IL Indianapolis, IN Fort Wayne, IN Detroit, MI
Wilmington, OH Pittsburgh, PA Buffalo, NY Charleston, WV

 

WSR-88D Cleveland Dual-Pol Products (via EXPERIMENTAL displays)

Click for Hydrometeor Classification data from WR-88D CLEClick for Differential Reflectivity from WSR-88D CLEStorm Total Precipitation (Dual-Pol) from WSR-88D CLE

     Hydrometeor Classification     Differential Reflectivity      Storm Total Precipitation                   

 

WSR-88D Radar Basics

Reflectivity Images

Base reflectivity image in precipitation mode - click to enlargeComposite reflectivity image in precipitation mode - click to enlargeThese images are just as they sound as they paint a picture of the weather from the energy reflected back to the radar. There are two types available on the web; Base (or ½° elevation) reflectivity and Composite reflectivity. 

Base Reflectivity is the default image. Taken from the lowest (½° elevation) slice, it is the primary image used to "see what's out there". There are two versions of Base Reflectivity image; the short range version which extends out to 124 nm (about 143 miles) and the long range version which extends out to 248 nm (about 286 miles). This image is available upon completion of the ½° elevation scan during each volume scan. View a sample base reflectivity image.

Composite Reflectivity images utilize all elevation scans during each volume scan to create the image. It is composed of the greatest echo intensity (reflectivity) from any elevation angle seen from the radar. It is used to reveal the highest reflectivity in all echoes.  View a sample composite reflectivity image.

Velocity Images

Base velocity image of Hurricane Rita September 23, 2005 - click to enlargeOne of the best features on the 88d Doppler radar is its ability to detect motion. However, the only motion it can "see" is either directly toward or away from the radar. This is called radial velocity as it is the component of the target's motion that is along the direction of the radar beam.

In all velocity images, red colors indicate wind moving away from the radar with green colors representing wind moving toward the radar. It is very important to know where the radar is located as that is your reference point for proper interpolation of the wind's motion.

Base Velocity images provides a picture of the basic wind field from the ½° elevation scan. It is useful for determining areas of strong wind from downbursts or detecting the speed of cold fronts. However, since the radar only measures radial velocity, the strength of the wind will always be less than what is actually occurring unless the wind is moving directly toward or away from the radar.

Storm relative motion image example - click to enlarge.Also, the surface winds are only for areas near the radar. As distance increases from the radar, the reported value will be for increasing heights above the earth's surface. View sample base velocity image.

Storm Relative Motion images are very useful images to look for small scale circulations (called mesocyclones) in thunderstorms. Often, these small scale circulations are areas where tornadoes form.

What separates storm relative motion from base velocity is the motion of storms are "subtracted" from the overall flow of the wind. As storms move, their own motion can mask circulations within themselves. This motion is removed to make the view of the wind relative to the storm. In effect, what is seen is the wind's motion as if the storms were stationary. View a sample Storm Relative Motion image.

More information: NWS JetStream - Online School for Weather (Doppler Radar)

Dual-Polarization (Dual-Pol) Technology

Dual-Polarization Radar - visual descriptionNational Weather Service radars provide forecasters information on precipitation intensity and movement (direction and speed). Dual polarization technology adds new information about the size and shape of an object, which will improve estimates of how much rain is falling, improving flash flood detection and warnings. During winter weather, dual polarization radar can tell the difference between rain, snow and ice, which gives forecasters a much better idea of what to expect at the ground.           Additional information: