Saturday, June 5, 2010

Tornadoes Ripping Across Northern Illinois

A reportedly "large" and long track tornado continues to move across portions of northern Illinois this evening.  Note the reflectivity (precipitation) and storm relative velocity (wind motion) images from the Chicago area (KLOT) doppler radar taken within the past 10 minutes:

On the above storm relative velocity image, the green/blue colors are motion toward the radar (which is located off the image on the upper-center portion of the screen), while the red/orange colors are motion away from the radar.  Note the "couplet" (where wind movement toward and away from the radar meet in a small, compact geographic area) showing strong rotation just North of Herscher.  This is the radar signature known as a "TVS" or Tornadic Vortex Signature.  This is most likely where the tornado is taking place on the ground.  This is a very dangerous situation taking place in a populated area.

Below is another view of the same rotation/TVS taken from the same radar, but on GRLevel2, which shows data in a higher resolution.  This image was taken about 10 minutes after those above.  The strong rotation is now just North/Northwest of Irwin:

As I was typing the above another updated GRLevel2 image came in; the rotation is now even better defined to the East/Northeast of Irwin:

No comments: