“So what gives Mr. Weatherblogperson? Most clouds had no ice and a very, very few did, ones that had some rain fall out of them. Below I have handcrafted a diagram with too many arrows and text on it, just for you, my friend, to help explain the mystery of yesterday’s clouds. I think, or rather hope, the excess text and arrowing will be self-explanatory…..
Overhsooting tops? Here’s the biggest one of the day yesterday. Most however, because they are colder than the environment, collapse quickly and as is often the case in days like yesterday, there is NO overshooting top by the time the ice and rain start to fall out the bottom of the cloud. But, you can bet before that happened there was one.
Forgot the nice sunrise and another faint rainbow, two mornings in a row! In case you missed them, again, here they are:
While yesterday’s Cumulonimbus clouds were sparse, their “overshooting” tops told you that they had pretty violent updrafts in them, ones that carried the top of the cloud past the tropopause (the boundary where the decline in temperature as you go higher stops). Above the tropopause sits the stratosphere, normally cloud-free and extremely dry.
These “overshooting” tops are due to inertia generated by the strongest updrafts in the cloud below them, they end up being much COLDER than the surrounding air in the stratosphere because the air is still expanding and cooling as the cloud punches through the tropopause. Like stones in water, they plummet back down quickly as they drift away from the root updraft. The worst volcanoes, like El Chicón in the early 1980s and, of course, Pinatubo in 1991, do this, too, and to a lesser degree these overshooting tops also inject aerosols and moisture into the stratosphere. These tops are usually easily recognized as a bulb-looking, whiter top above the flat anvil, the anvil representing cloud top ice that has been stopped by the tropopause barrier and has spread out.
Seems we have a day similar to yesterday ahead for today, but the models suggest an uptick in activity tomorrow. When the thunderheads are more isolated, they are more photogenic I would have to say, especially against the backdrop of the darker blue skies we have now. And with no haze around, something that often can accompany higher humidities such as we have had over the past week or two, our cloudscapes are especially pretty I think.