By Sue KILPATRICK

“May your trails lead you to the most amazing view. May your mountains rise into and above the clouds.”
— Edward Abbey

Last week left us with little doubt that summer was here to stay. The foothills were blasted by temperatures well over 100 degrees. Thunderheads billowed over the mountains, bringing brief rain showers to communities east and south of us. The sunsets were truly created for our appreciation, if not certainly for the artist. The nights remained a warm breezy 80 degrees. At the beginning of this week the weather began to gradually cool down to the more average temperatures of summer. So what creates these weather phenomena? The answer reminds us more of India than the American southwest: monsoons.
The condition we experience is known as the North American monsoon, also referred to as the Arizona or Mexican monsoon. A combination of an extensive land area, which heats up during the summer close to a large sea or ocean, in this case the Gulf of California, helps set the stage. Then add an area of high pressure over the four corners region of the U.S. Southeasterly winds develop pulling moist air up from the gulf. As the flow of damper cooler air moves north it replaces the heated air rising off the desert floor. The atmosphere becomes very unstable, the humid air is uplifted and condensation occurs. Cumulonimbus clouds or thunderheads are formed often resulting in thunder showers. These storms are short lived, but can bring torrential rains. During this time Arizona and Mexico receive their majority of rain for the season. Being further to the west and close to the cold Pacific Ocean, besides an occasional thunderstorm and clouds, the effects of the North American monsoon are minimal in our area.
Crescenta Valley weather for the upcoming week is predicted to remain quite stable with daytime highs in the mid 80s and nighttime lows in the mid 60s. Early mornings may be influenced by a light marine layer. July’s full moon will arrive on Monday. At this time of year male deer begin to grow their new antlers. Therefore the Native Americans referred to it as the Buck Moon.
“O summer day, surpassing fair ,with hints of heaven in earth and air.” – Eben Rexford

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