I attached a little goody showing the July 24th tornado. It's the storm relative radial velocity image. What it shows is the motion of precipitation in storms. Precipitation moving toward the radar has negative velocity shown in blues/greens and precipitation moving away from the radar has a positive velocity, shown in yellows and oranges. This is how you identify rotation in storms and spot tornadoes.
Look near Barnstead and you can clearly see a couplet, which is a blue pixel touching a red pixel. Only way for a rain to be moving towards and away the radar in such a small area is for there to be rotation.
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