It’s raining….or not

I noticed something on the radar a while ago and thought you all might find it interesting. It’s actually raining up above us right now, but it’s not reaching the ground. That is called virga. This shows up nicely on radar right now.

Keep in mind that the radar we use is located near Nashville. As that beam goes out from the radar site, it gets bent upward. That means that as it goes out in distance it goes up in altitude.

In the imagery below, the radar beam is high enough in the atmosphere to detect precipitation by the time it gets 100 miles or so from the radar site. Meanwhile, nothing is detected near the radar. The precip is evaporating before it hits the ground.

Those green specks you see near the radar site northeast of Nashville is just “ground clutter”. The beam is so low to the ground near the radar site that it bounces off buildings, trees, hills, etc. That sends back “fake” returns.

Our relative humidity here in Crossville right now is only 33%. That’s a far cry from being moist enough for rain to fall. Virga also makes for interesting looking clouds. Step out and look up if you get a chance.


Still imagery of the radar image.



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