Charles E. Burchfield (1893-1967), Windswept Sky, September 10, 1916; watercolor on paper, 14 x 20 inches; Burchfield Penney Art Center, Gift of Tony Sisti, 1979
The focus of this painting is what is happening many thousands of feet above the surface. The clouds are cirrus (Ci), typically thin and formed by ice crystals high in the atmosphere. As they form in bunches (hooked and fibrous), they are often referred to as cirrus uncinus (Ci unc) or ‘Mare’s Tails.’ At heights above 20,000 feet the air is frigid at about -40°F, and colder as you go higher. This cold air cannot hold much moisture, so these clouds cannot produce rain. The presence of Ci unc clouds suggests rapidly flowing upper air winds, the fastest of which is called the ‘Jet Stream.’ The direction of these upper air winds is generally from west to east, so based on the position of the tree’s shadows the viewer is looking west into the painting. Generally, high winds (whether at ground level or in the upper atmosphere) are an indication of change. If the cirrus clouds thicken over time, it may be an indication of the passage of a warm front and possible rain in about 24 hours. The message in the painting: enjoy this beautiful day as tomorrow may bring inclement weather.