Drag out custom shape mentioned above as a path, or create one. I chose the one I already had sitting around. Filled it with bright yellow color. Deselected path.
New layer. Select transparency of first layer. Slide foreground color a bit further down the hue scale into an orange-ish. Filter>stylize>wind, at least twice. (Original is twice this size.) Deselect, gaus blur, bout 4 pixels. Repeat 2, 3, 4, 5 times.. whatever makes ya happy till you get the hue all the way down to red, contracting the selection a bit further each time.
New Layer. Select transparency of red layer, contact and fill with your middle orange. Should be pretty well feathered. Repeat with bright yellow.
New layer. Select path. Stroke bright yellow with medium hard brush.
Convert path to selection, invert and go clean up all the blurred layers.
