Convection

2006-09-09 06:36:26.000 – Neil Lareau,  Observer

It was nice up here yesterday. Highs were in the mid 50s and for most of the daylight hours winds only registered in the single digits. Fair weather cumulus occupied about half the sky for most of the day and demonstrated the wonders of convection. Tumbling eddies were obvious embedded within the overall NW-SE drift of each cloud. Over the Rocky Branch ridge a more vigorous updraft formed a quickly growing cumulus mediocris cloud. It looked to have much greater ambitions, trying for the ultimate status of cumulonimbus, but alas the crenellated top regularly caved to the entrainment of cold air, quashing its upward mobility.

Clouds may be permitted to attain loftier heights today. A cold front dropping down from Canada will destabilize the atmosphere. Clouds will grow vertically reaching into the sub-freezing air aloft, ice crystals will spread from these cloud tops, electrical charges will become separated vertically through the cloud structure, and if things are just right an arc electrical current will rend the air. Actually that isn’t true, it will fuse the air. If you’re close enough you might even smell ozone (O3). You don’t want to be close enough. Keep that in mind if you’re planning on hiking above tree-line today.

Today’s cold front is aptly named. The air behind it will be, well, much colder. Summit temperatures will drop to around the freezing point tonight, and tomorrow night they will likely drop to the upper 20s. Take that bugs.

Neil Lareau,  Observer