Sustained Storms on the Transvaal Highveld

The structures of sustained storms on four days as revealed by a high-resolution weather radar are described. No storm lasted for more than a few hours. Practically all of them were multicellular. Systematic discrete growth caused some complexes to remain virtually stationary while others deviated significantly from or moved against the directions of the midlevel winds. One long-lived, fairly severe hailstorm was unicellular and it deviated strongly from the general directiton of storm cells on this day. It was not a supercell nor were any others that were studied. Long-lived storms are relatively rare on the Transvaal Highveld and all those studied have had characteristics indicating unsteadiness of their airflows.