miqrogroove

Centered on the Battle Creek Airport

Ever wonder what happened to that storm from last year?  Well, the trees have been removed and the damage repaired.  I heard the storm caused over $25 million worth of damage but was not classified as a tornado.  When a twister touches down on the earth, trees end up thrown in every direction.  If that type of wreckage is not found, then the storm is merely a severe wind event.  Still, it only takes one look at a storm like this to know to stay out of its way.

I recently familiarized myself with the National Climatic Data Center (NCDC) in the hope that I could find an easy way to grab a local 24-hour radar loop.  I didn’t really find what I was looking for because the NCDC Archive is more vast than fast.  While I was experimenting, I grabbed the data for this memorable day back in 2011 and put together a nice animation from it.

My Radar Loop From May 29, 2011 (5 MB animated GIF)

You may be unfamiliar with this type of radar, so I will point out a few of the cool things that can be seen here.

This is a “radial velocity” loop, which has different coloring from a typical “reflectivity” radar image.  Instead of showing where the rain clouds are located, this imagery shows how fast the rain clouds are moving by putting brighter colors on faster clouds.  This is useful for distinguishing strong storms and tornadoes from an average thunderstorm.  Otherwise, they would all have the same reflectivity and look identical to each other on the usual radar.

Radial velocity works perfectly for this particular storm for two reasons:  1. The storm is moving from west to east and, 2. The storm is positioned due south of the radar station as it forms.  This sets up a right angle between the storm’s overall motion and the radar beam, causing any wind shear within the storm to appear in full contrasting colors on the image.  As the storm moves toward the east sector of the radar scope, the angle of the radar beam changes, causing the color contrast to gradually decrease.  The maximum value recorded on this loop was +40 m/s, meaning 90 miles per hour away from the station!