Clouds Amber and James

How are clouds formed?  Clouds form by condensation.  The sun heats the earth and the air above it.  This warmer air will rise up into the atmosphere.  As the air rises, it cools because it’s expanding, but it is traveling further away from the heat source.  The air will cool to its dew point, the air is saturated and the water vapor can condense into tiny particals called condensation nuclei.  When enough droplets condense, and the clouds become visible.

Altitude High level clouds are about 20,000 feet. Mid-level clouds appear between 6,500 to 20,000 feet. Low level clouds lie below 6,500 feet. Vertically Developed clouds can grow to heights in excess of 39,000 feet.

Cirrus Clouds They tend to have feathery strands called mares' tails. These often indicate the approach of a warm front marking the advance of a storm system. Whenever there is moisture in the upper levels of the atmosphere, cirrus clouds will usually form.

Cirrocumulus They are small rounded puffs that usually appear in long rows. If these clouds cover a lot of the sky, it is called a "mackerel sky" because the sky looks like the scales of a fish. Cirrocumulus are usually seen in the winter time and indicate fair, but cold weather.

Cirrostratus Cirrostratus indicate a significant amount of moisture in the higher levels of the atmosphere. A layer of wide spread cirrostratus may indicate one of two things. The first being the approach of an active disturbance. The second being an inactive high level moisture outflow.

Altocumulus Cover a large area for a long time. indicate an active moving weather system If cloud layers at other levels can also be seen, an organized weather system may be approaching the area.

Altostratus form when there is a significant amount of moisture present. These clouds often are carried long distances without significant change.

Stratus Very little precipitation ever falls from stratus clouds. they appear very large since they are so close to the ground. Stratus clouds also represent the transition to or from fog and cumulus clouds.

Stratocumulus may occur often along coasts. the clouds accompany larger scale weather systems Stratus clouds indicate low level moisture.

Nimbostratus Nimbostratus clouds are precipitation clouds. Nimbostratus clouds should be watched closely because most thunderstorms start with a nimbostratus phase.

Small Cumulus &Swelling Cumulus Cumulus clouds are fair weather clouds. If they are seen in the afternoon, there is no threat of showers. called towering cumulus. They are taller than they are wider. For a swelling cumulus to develop, there must be some instability in the atmosphere. The earlier in the day these clouds start the form, the larger the threat of strong storms later in the day.

Cumulonimbus Cumulonimbus clouds are thunderstorm clouds. Precipitation is always present with these clouds. Often, severe weather will occur. develop from swelling cumulus. When lightning and thunder are detectable, the cloud is a cumulonimbus.

Mammatus Mammatus clouds are an indication of very severe weather. Large mammatus clouds indicates that there is a very strong thunderstorm near by. The pouch like structures are a result of sinking air.

Lenticular Clouds These clouds form as air passes over mountains. to form the air must be fairly dry yet still contain some moisture. air will move in a smooth arc over the mountain.

Kelvin-Hemholtz Clouds These clouds which have the appearance of breaking waves usually last for a few seconds to a few minutes. In other words they indicate a large change in wind Caused by speed over a small increase in altitude.

Fog Fog is a dense cloud of water droplets, or cloud, that is close to the ground. The moister in the air condenses and forms advection fog, or “land fog”. Another type of fog is sea fog, which is carried from place to place on air currents, it hardly ever dissipates because it continuously forms.