An advantage of single-radar vs. merged az shear jumped out right at the start of today’s simulation: lag time. The single radar product looks to have a 2-3 minute jump on the merged data with respect to low-level rotation, as shown in the time sequence below. The tightening/strengthening rotation couplet begins to jump off the screen in the single-radar data at the 2000 scan further intensifies through 2004. The area of strengthening low level rotation is much more muted in the merged data at 2000. It is more noticeable in the 2002 scan before becoming quite obvious by 2004. This small lag may not be significant, but it could be the difference of a  few minutes worth of lead time in warning decisions.

Dave Grohl