Mamatocumulus These clouds extend downward from a cumulonimbus cloud, they appear as bubble like bulges. They are formed by a cold downdraft near the edge of a thunderstorm and as a result can accompany severe weather conditions and in particular tornadoes. Coverage Cloud coverage is classified into the following four categories. Movement Clouds move in the direction the wind is blowing at the altitude of the clouds. Clouds can be moving a different direction than the observed wind at the surface.
Rainfall is recorded by a rain gauge.
Snowfall can be measured by using a ruler to record the depth. If the precipitation occurs while the wind is strong precipitation measurements must be measured carefully. Snow depth would vary considerably because of drifting so measure the depth at many flat, open locations and take an average estimate. In making an observation while there is precipitation, note the time precipitation began and ended. Wind has a speed and a direction.