By Sue KILPATRICK

“…on a summer’s day watching the clouds float across the sky, is by no means a waste of time.”
— John Lubbock, English archaeologist, biologist and politician

This past week has been one of temperature fluctuation. Our extreme heat warning was replaced by an Alaskan low pressure system that ushered in cool marine air. In less than 24 hours the mercury dropped 40 degrees. On Friday afternoon I was in the pool to cool off and by late that evening fog was covering the Verdugo Mountains. Although the change in weather has made life more comfortable, there is one aspect of the heat that I really do like (besides summer evenings). To this day, I hold it dear in my memory.  As a child my mom would call to me, “Susie, come  look at the thunder heads coming over the mountains!” I remember being transfixed by them.
Scientifically these masterpieces of nature are known as Cumulonimbus clouds. Most occur in the late afternoon on a hot summer day in the southwest. With a combination of heat and moisture these clouds can rapidly develop into a thunderstorm. They seem to appear out of nowhere and can disappear as mysteriously. But during their short life they can create heavy rain, flash floods, lightening (which kills dozens of people and starts thousands of fires every year), hail, powerful winds and possible tornadoes. As storms go, these are too small to detect by computer weather models. These thunderstorms are nature’s way of distributing the Sun’s energy.
As promised, the first day of school was refreshingly cool. Daytime highs have been in the mid 70s and nights have dipped below 60 degrees.  As the week progressed it has warmed into the 80s and low 90s. Looking to next week the temperatures will cool again to the 70s during the day and upper 50s at night. Do I detect a bit of Autumn in the air? In another three weeks it will officially arrive, so enjoy the last days of summer!
“Happily we bask in this warm September sun …” – Thoreau

Sue Kilpatrick is a longtime CV resident and amateur weather watcher. Reach her at suelkilpatrick@gmail.com.

  Crescenta, weather