Ask Heather - tornadoes on radar

KNOXVILLE, Tenn. (WVLT) -- Many in our area have seen what a tornado can do, but Mike Fralix wanted to know how Meteorologists spot tornadoes on the radar in this week's Ask Heather.

First off, the definition of tornado is that it's on the ground. That's important to remember, because the radar cannot scan all the way to surface.

What we can see on the radar are indications of a possible tornado. That's why it's easier to have confirmations of tornadoes in the wide-open flat lands, like the Midwest U.S., where people can spot storms from miles away and chase storms.

The picture attached and the video shows an example of a tornado on the radar, from the National Weather Service. This is the classic hook echo. You can see the rain span out, in the upper right corner, in what's called a mesocyclone.

The rain and hail from this storm sweep up and out in the hook.

The area without any reflection, or clear radar, is the updraft. This is the inflow notch of the supercell, coming into the tornado in the bottom of the hook.

The second image of reds and greens is called the relative velocity. You won't see this one very often, but it's how meteorologist can examine a storm's inner workings. The green shows the storm that's moving towards the radar and the red indicates motion away.

So the red and green right next to each other, is showing the rotation in the storm.

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