For all the weather I’ve witnessed and cloudscapes spotted over decades, this was a fascinating first: a shelf (arcus) so high, with mammatus so low, that they were colliding. The storm was a high-based, High Plains ex-supercell, producing mammatus from the lowest part of the anvil structure in middle levels, almost adjacent to the core. In less than an hour, countless hundreds of mammatus clouds would festoon the sunset sky from the higher anvil, on the back side of these storms.
18 NNW Cheyenne WY (6 Jul 19) Looking SW
41.4037, -104.9311
Arcus Smacking Mammatus
For all the weather I’ve witnessed and cloudscapes spotted over decades, this was a fascinating first: a shelf (arcus) so high, with mammatus so low, that they were colliding. The storm was a high-based, High Plains ex-supercell, producing mammatus from the lowest part of the anvil structure in middle levels, almost adjacent to the core. In less than an hour, countless hundreds of mammatus clouds would festoon the sunset sky from the higher anvil, on the back side of these storms.
18 NNW Cheyenne WY (6 Jul 19) Looking SW
41.4037, -104.9311