Prior to 21:09Z, the NTDA algorithm was keying in on sidelobeing issues ahead of the storm, the the NMDA held strong indicating no rotation. At 21:09Z, a hook echo began to form with a solid rotational signature in a good dat region, and both algorithms picked up on the signature quickly. Using the objective analysis, seeing the NTDA put out a Probability >50% with the NMDA put out an Avg AZShear in the bottom 3 scans of 22.9 *10 ^-3 /s, helped add confidence to the decision to warn quickly.

A couple times though (like at 21:15Z as seen below), the algorithms were still keying in on bad low-level data due to sidelobing from time to time. Velocity images compared to Correlation Coefficient show where more reliable data is located.

-#ProtectAndDissipate