The spectacular sunsets of recent evenings are a rare summer treat, Michael Lewis confirmed. They are normal in the fall, winter and spring in Southern California. Unusual winter-type storm activity is the source of this surprise.
Lewis, a meteorologist with the National Weather Service, reported that the clouds that are catching the dazzling rays of the setting sun are the remains of thunderstorm activity, which has been generated by the movement north of moisture from Mexico and the Gulf of California, and a low-pressure system aloft.
Two layers have been involved during most evenings. The most vibrant colors are those reflected from ice crystals in the upper air at around 40,000 feet. Scud clouds, the remains of middle-level clouds that have collapsed, add another dimension between 2,000 and 6,000 feet--a gold and then pearl-gray lace through which the brilliance of the rose-shaded upper levels can be viewed.
The precipitation, with some exceptions in the deserts and mountains, hasn't been substantial, although the activity has cooled the region by at least 6 degrees. But that seems of secondary importance compared with what this has done to inflame the evening sky.