Never heard anything like that before....

It's 5:30 - 5:45pm, storm is rolling in from the North. News stations are predicting it'll pack a whallop but, it's moving slow and not expected to hit my area for another 30 to 45 minutes.

I think "Finally I get a break from the rain and I can go cut my front lawn while it's relatively dry". I step out into the back yard and hear the strangest noises I have ever heard in my life. It was the approaching storm and it was the most disturbing sounding thing I have yet to hear.

While I am pulling my mower out of the shed I am listening to what I can only describe as a diesel electric locomotive with bad windings on the generator and drive motors. That is literally what this storm sounded like! A constant low level rumble with very little fluctuation in tone and absolutely none of the typical booms of thunder. All laced with an electrical cracking and popping akin to a shorted high voltage line with a periodic sharp snapping arc fault like effect. This went on for about 15 minutes while I pulled, checked, gassed, and pushed the mower toward the front lawn.

No sooner than I got the door open to the garage to pull the mower through the hail came. Rather than fight the mower through the door I dashed to the back patio with it. Within minutes my nearly 8000 sq foot back yard was covered in grape sized hail to about 1" deep.

Well, that's about the best description I've ever read of what a tornado sounds like...

I was thinking the same thing. And yet, there has been no tornado reports nor were there any reports of a hook echo in radar. Just a crapton of dense hail. I wonder if the desity of the hail being formed in the front edge of the storm is what triggered the effect.