30 March 2013

How To Tell If You Are About To See Baseball Size Hail.

Posted by Dan Satterfield

How a three body scatter spike forms. Image from NOAA/ NWS.

I’m back in Oklahoma for a few days visiting with my daughter and her dog Sebastion (AKA Bashee). We had a nice thunderstorm cluster pop up to our northwest here in Oklahoma City, and I immediately knew that someone was about to get some very large hail. Take a look at the radar image above. I have red arrows pointing toward what meteorologists call a THREE BODY SCATTER SPIKE.

This is a false echo that is caused by large hail (coated in water) bouncing the radar beam down to the ground, back to the hail, and then back to the radar. Ice, with a film of water, around it makes a very good reflector of radar imagery and this is also why we see very high reflectivity values in the core of the storm.This extra distance the radar beam travels shows up as spike behind the hail core of a thunderstorm. You usually only see these in cases of very large hail. In this case there were widespread reports of hail the size of baseballs!

Here is another 3 body scatter spike near El Reno Oklahoma a couple of hours earlier:

..and below is the storm  as it began to weaken near sunset.

Dan's pic (iPhone 5)