Weather develops as temperature, moisture, pressure, and moving air interact over short timescales. Coverage includes clouds, rain, snow, winds, storms, hurricanes, tornadoes, observation, and the scientific principles behind forecasting.
Cirrus clouds often look like brushstrokes because their solid particles are falling through winds that change with height. The fibers are not made of liquid droplets but almost entirely of ice crystals, suspended and reshaped in the cold upper troposphere. What appears to be a simple white streak...
A lenticular cloud can appear fixed above a mountain while strong wind streams through it. Its polished edges barely move, even as other clouds cross the sky. This apparent stillness is possible because the cloud is continually being rebuilt: water condenses along the rising portion of an...
Few cloud formations reverse familiar expectations as dramatically as mammatus. Instead of rising in cauliflower-like towers, smooth lobes hang from the underside of a cloud, sometimes filling the sky with a field of rounded pouches. They are most recognizable beneath thunderstorm anvils, where low...
A mature cumulonimbus can rise from a dark, rain-filled base to the upper boundary of the troposphere in less than an hour. Most of the cloud stops there and spreads sideways into an anvil. In the strongest thunderstorms, however, the central updraft carries a dome of cloud above the anvil and...