Siobhan Braun 2 p.m., Sept. 18
Temperatures, Sunsets, and Fremont Cottonwoods
Low-lying Temperature Inversions commonly occur in San Diego as winter approaches. During the night and morning hours, a meterological condition often occurs in which the "normal" higher-you-go-the colder-it-gets trend is reversed. At such times cold marine air lies below a stable layer of warmer air originating from inland locales. Whenever moist air is trapped below a low-lying inversion layer, dense fog forms on or near the ground, and San Diego International Airport is sometimes forced to suspend operations.
November's and December's Picturesque Sunsets and sunrises are no accident. This is the time of year when high cirrus clouds, often the precursors of storms, sweep through our area with some regularity. When cirrus or other lofty clouds are present, low-angle sunlight bathes the undersides of these clouds in a crimson luminescence. This effect is most noticeable a half hour to a few minutes before the sun rises and a few minutes to a half hour after the sun sets.
The Fremont Cottonwoods along the San Diego River in Mission Gorge are now showing off their best autumnal foliage. You can park at the Old Mission Dam historic site or the Mission Trails Regional Park visitor center and explore the riparian area by way of riverside trails, or by walking, bike riding or skating along the bike path high above the river's south and east banks. Large cottonwoods can also be seen along other watercourses throughout the San Diego County backcountry, including along the Sweetwater River near Cottonwood Golf Course, and in Cottonwood Valley, east of Pine Valley along Interstate 8.