![]() Notice how there is no real reflectivity return in the inflow region. This is only really feasible if you have very strong rotation in the storm. Hook echoes are a sign of a strong rear flank downdraft coupled with a strong inflow region. This defines what is commonly called the "hook echo" that you so often hear about on TV. Notice how since the rear flank downdraft-the downdraft air getting wrapped around the mesocyclone-is forced out into the inflow air, and there is a protruding area of reflectivity return on the southern side of the storm. Does this structure start to look familiar? This pattern of reflectivity return is the iconic signature of a supercell thunderstorm. The light green outline here shows generally what we'd expect to see on radar:īasically we expect to see radar reflectivity returns everywhere that the downdraft is dominant. Then we also expect a narrow band of radar reflectivity returns behind the mesocyclone corresponding to that portion of the downdraft that gets wrapped around by the rotating air. There would also probably be a weaker area of returns (or no returns) where the inflow region happened to be, since that warm, buoyant and rising and rain is probably not falling through that area. We expect to see lots of returns out ahead of the storm because that's where most of the rain-filled downdraft air is going. So what would our resulting radar reflectivity image look like for this kind of situation. Here's a block diagram of the two paths I just metioned: This part of the downdraft is usually called the "rear flank downdraft". Thus, in most supercells, we see an intense, though narrow band of rain wrapped around on the back side of the mesocyclone. However, because the center of the storm is rotating, some of the downdraft air can get wrapped around the back side of the storm as well. This large area of precipitation and sinking air out in front of the mesocyclone is called the "front flank downdraft". Thus, we'd expect to see a lot of radar returns out ahead of the mesocyclone area, since radar beams reflect off of raindrops. The same jet streaks that are providing the divergence aloft to support the updraft can also carry the cold, rain-filled air off ahead of the storm and away from the updraft. A lot of the air gets pushed out in front of the updraft (to the east, typically) by the strong upper-level jets that we find at the top of the storm. The downdraft air takes one of two paths (usually). But in an organized storm like a supercell, this doesn't happen. Now, for the storm to keep growing and maintain itself, the downdraft can't sink into the updraft-this would choke off the updraft and kill the storm. ![]() Eventually, at the top of the cloud, there is rather cold, rain-filled (or hail and ice filled too) air that is no longer buoyant because it's so cold. As the warm, moist air rises, it cools off, and as the air cools off, water vapor condenses back out into liquid water and rain is formed. Thanks to its extensive radar coverage, RainViewer can also generate an accurate weather forecast for the next week.īelow you can find an extensive list of radars in regions where precipitation and unstable weather currently occur.The inflow rises up as it enters the storm, forming the updraft. Having analyzed this data, the app shows the current weather forecast and how the weather will be changing during the day. RainViewer has access to the data from more than 1000 weather radars across the world. It will automatically search the map, allowing you to learn where the rain, snow, or hail was before it reached your areas and where it will be moving. Use the playback controls to turn on the map animation. We are also working on the display of the mix of precipitation types, such as rain, freezing rain, sleet, and/or snow. Rain and snow are shown in blue whereas showers are marked with orange and red, and hail - with pink. The precipitation type is marked with different colors on the map. It is possible to analyze both types of data in order to identify if the storm can cause severe weather. A modern weather radar is mostly a Doppler radar that can detect the motion of rain droplets in addition to the intensity. With the help of a weather radar map, it is also possible to predict where the rain will be moving next and how intense it will be. ![]() A weather radar can determine the precipitation type (rain, snow, hail, etc.) and spot its location. The Weather Radar Map Live page shows areas where precipitation is currently expected.
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