![]() ![]() It provides the highest-resolution reflectivity available from NEXRAD radars to a distance of 230 kilometers from the radar. The Level II velocity product has a resolution of 0.25 kilometers by 0.5 degrees. Level II velocity is available to RadarScope Pro Tier Two subscribers. It’s the same data as super-res reflectivity but at a lower resolution and larger coverage area. With proper interpretation, spectrum width can provide an indication of turbulence, which can be helpful in identifying conditions associated with severe thunderstorm activity.ĭigital velocity is the standard velocity product distributed in the NEXRAD Level III product suite. mesovortices) lower values indicate a narrower range (smooth flow e.g. Higher values of spectrum width correlate to a wider range of velocities being observed (turbulent flow e.g. Spectrum width is a measure of that variation. Within any volume that is sampled by a radar, there can be a wide range of motions being observed. You can learn more about storm relative velocity on this expanded info article or on this National Weather Service page. As with super-res velocity, green is motion towards the radar and red indicates motion away from the radar. When storms are moving quickly, this makes it easier to spot green/red velocity couplets that are indicative of rotation and which might be masked out by the motion of the storm. Super-res storm relative velocity is super-res velocity with the average storm motion subtracted out. Super-res velocity is available at four different tilts or beam angles, with tilt 1 being the lowest to ground level. The super-res velocity product has a resolution of 0.25 kilometers by 0.5 degrees. But it gives you a fairly good idea which way a storm is heading. Note that the radar can only detect the component of the velocity vector along the radar beam, so this isn’t a full picture of the wind field. They can be difficult to interpret without training and experience, but Doppler velocity products can be used to detect the overall movement of a storm as well as relative motion within the storm itself, such as rotation. Negative values (green in RadarScope) indicate motion toward the radar, while positive values (red in RadarScope) indicate motion away from the radar. The velocity products in RadarScope use the Doppler effect to determine how fast the particles in the air are moving relative to the radar itself. ![]() With all of these products in the palm of your hand, you can be more confident in identifying the type of precipitation that the radar is observing and falling at the surface.Doppler velocity products indicate storm motion toward or away from the radar. While Precipitation Depiction can provide a good guess of precipitation type, other products that can also be used to determine precipitation type, such as dual polarization products. The relatively high reflectivity values in the snow may indicate melting snow. Southeast of Salt Lake City, precipitation is being depicted as snow. Precipitation west of Salt Lake City was identified as rain by the Precipitation Depiction algorithm (which is consistent with observations from automated stations). This image has both rain and snow near Salt Lake City. At the time of this image, heavy snow was being observed at the Billings observing station.īillings, MT Reflectivity and Precipitation Depiction Notice it shows higher values than the previous image, especially near Billings. Here are reflectivity and precipitation depiction data from Billings, MT. Snow typically has reflectivity values between 5 and 20 dBZ but can be higher if it is melting. Notice again the grainy appearance of the snow in the reflectivity image?Īberdeen, SD Reflectivity and Precipitation Depiction Now, let’s look at the images below with only snow. A snow echo will typically have a fuzzy or grainy appearance on a reflectivity image. Also, note the significantly higher reflectivity values for the rain than for the snow. In the Precipitation Depiction images throughout this blog, green and yellow shades represent rain, and the blue shades represent snow. I’ve captured images of snow in South Dakota and rain near Memphis. Let’s take a look at a few different images that can help in the future.įirst, let’s compare reflectivity for echoes that are all rain and all snow. There are a few ways to accomplish this task. As winter approaches, you may start wondering how to identify snow while using RadarScope. ![]()
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