Sunday, April 24, 2011

TBSS Indicates Large Hail

Every now and then, a interesting phenomenon occurs on radar when a storm has large hail. It's called a Three-Body Scattered Spike.In the above image, can you spot the "spike" of blue shooting out from the NW part of the storm from last Tuesday? That is not a line of light rain, but rather a line created from the returns of large hail. As the radar beams goes out, it hits the precipitation, and comes back. The time or duration indicates how far the precipitation is from the radar.

At times, large hail sends the signal from radar in all kinds of directions. The reason for the spike is because the radar "thinks" the rain is farther away because it took the signal longer to get back to the radar dome. Therefore it thinks the rain is farther away.
So instead of the signal hitting the precipitation and going back to the radar, it hits the hail, reflects to the ground, reflects back to the hail, and THEN back to the radar. Therefore the "spike" appears. We saw this a few times last Tuesday night. (explanation image from several online sources)

I'm heading to Church! Have a great day as we celebrate the Resurrection!


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