Dutchsinse | 4/22/2012 -- Circle sweep, Scalar Squares, Sawtooths = (72hr) CA OR WA ID CO TX MN WI GA FL

Full website post here with the screenshots of each event. Watch over the next approx. 2-3 days for possible severe weather development to hit each area epicenter or VERY close (within 50 miles usually).
http://sincedutch.wordpress.com/2012/04/22/4222012-circle-and-sawtooth-sweeps...
I believe a ground based station , using a HAARP type technology (i.e. a ground based station that emits a HF frequency to induce an effect in the atmosphere or higher).... possibly even a tweaking of the current RADAR system itself .. is being used to emit VHF or EHF .. could conversely POSSIBLY produce VLF (very low frequency) or relay very low frequency on using the tiltable AIM method.. to "heat" the atmosphere above each station .. to create an "artificial ionospheric mirror = AIM" .. IN THE ATMOSPHERE !
I believe this heating to be INDUCING or ACCENTING current coming systems, and may even DRAW the storm to each station that emits a series of strong "pulse" returns.
These "geometric modulations" are done to increase the amplitude of the waveform being emitted. Whatever that waveform is.. its showing as a quick flash into the high RF.. and as the flash intensity increases .. so does its geometric modulation appearance on the screen.
The pie-shape is explained using the Fourier heat dissipation analysis. The square , rectangle, sawtooth, and circle sweeps are explained in the stanford VLF geometric modulation papers.
Both linked here:
geometric modulation:
http://vlf.stanford.edu/pubs/geometric-modulation-more-effective-method-steer...
Fourier Heat dissipation analysis:
http://en.wikipedia.org/wiki/Heat_equation
Tiltable AIM in the atmosphere using a ground based station (mini-HAARP relays) :
http://www.google.com/patents/US5041834