Read the sky: clouds as a six-hour forecast
Every cloud shows you something the air is doing. Work out what an anvil, a lens over a ridge, a ring around the sun, or a row of hanging pouches tells you about the next few hours. Each question starts with a photograph, and each answer comes with a diagram of the mechanism.
Questions
- Not answered. Thin hooked streaks spread across the sky through the morning and slowly thicken. What do the next six hours look like?
- Not answered. A pale ring circles the sun about an outstretched hand-span away from it. What does the ring prove about the cloud you are looking through?
- Not answered. The sun has gone from a sharp disc to a pale smear behind a grey sheet, and your shadow has disappeared. How far along is the front?
- Not answered. Cirrus came through last night, a halo appeared this morning, and now the sun is a watery blur. The deck keeps lowering and thickening. Name the cloud it becomes when the rain starts.
- Not answered. Yesterday the contrails vanished a few plane-lengths behind the aircraft. Today they hang around for hours and spread into broad fuzzy bands. What changed?
- Not answered. Small puffy clouds dot the sky, each wider than it is tall, and every one has its flat bottom at the same height. Why do the bottoms line up?
- Not answered. The air is 27 °C and the dew point is 15 °C. Roughly how high is the base of the cumulus forming overhead, in metres?
- Not answered. A tower has grown fast all afternoon and its top is still a crisp, hard-edged cauliflower. What does that sharpness tell you?
- Not answered. The storm's top has stopped climbing and spread sideways into a flat sheet. What stopped it?
- Not answered. Rounded pouches hang from the underside of a storm's anvil. What is the air inside those pouches doing?
- Not answered. A low, layered wedge stretches across the horizon under an approaching storm, with brighter sky underneath it. What arrives first, and how soon?
- Not answered. A smooth lens-shaped cloud has hung in the same spot over a mountain for three hours, while the wind at that height is around 80 km/h. How does it stay put?
- Not answered. At nine in the morning, small turrets and tufts are sprouting upward from a mid-level cloud layer. What does that suggest about the afternoon?
- Not answered. Grey streaks hang below a cloud and fade out well above the ground. What should you expect underneath them?
- Not answered. Electric-blue filaments glow in a deep midsummer twilight, an hour after the sun has set. What do they tell you about tomorrow's weather?
- Not answered. Which of these sights mean the weather where you are standing will actually change within the next six hours?