Weather Flashcards
What are the levels in the atmosphere?
Troposphere, Tropopause, Stratosphere, Mesosphere, Thermosphere
What is the Troposphere level?
Surface to 36,000 feet
What is the Tropopause?
Lid of water vapor, between the Troposphere and Stratosphere
What is Convection
Cold air sinks, hot air rises
What are the 3 cells involved in atmospheric circulation?
Polar, Ferrel, Hadley
How far does the polar cell extend before falling?
60 degrees latitude
What are variations in altimeter settings between weather reporting points caused by?
Unequal heating of the earths surface.
What do closer millibars mean?
Higher winds
What are the 3 factors involved in Coriolis Force?
Distance traveled, Position on the earths surface (latitude), Speed of the object
What rotation will high pressure result in?
Clockwise
What rotation will low pressure result in?
Counterclockwise
Explain frictional force.
Because of earths rotation and coriolis effect, wind is pushed to the RIGHT below 2,000 ft.
What is the effect of friction on wind?
Wind will shift direction when near the earths surface.
What is the result of convective circulation patterns associated with sea breezes?
Cool dense air moving inland from over the water.
Convective circulation patterns associated with sea breezes are caused by what?
Temperature differences between land and sea.
Is moist warm air stable or unstable?
Unstable
What is sea breeze?
Warm land, cool water (daytime) blows from water.
What is land breeze?
Cool land, warm water (night) blows from land.
What is valley breeze?
Mountain slopes heated by the sun create upslope flow. (5-20 kts.)
What is mountain breeze?
At night, high terrain cools off, becoming cooler than air below. Air flows downslope. ( 5-15 kts. Sometimes exceeding 25kts.)
What is katabatic breeze?
Downslope wind, mostly referred to when stronger than mountain breeze
Which is more stable? Dry cool air or Moist warm air?
Dry cool air
Explain evaporation:
Liquid water converts to invisible water vapor.
Explain Condensation:
Water vapor changes to liquid (this cloud development)
Explain Sublimination:
Ice to water vapor.
Explain Deposition:
Water vapor to ice.
Explain Humidity:
Moisture in the air
What is relative humidity?
Actual amount of moisture in air compared to the total amount of moisture that could be present at that temperature.
What is Dew Point?
Temperature at which the air must be cooled to become saturated.
What is Saturation?
Air contains 100% of moisture possible at a specific temperature.
Cloud forms calculation:
Temperature - Dewpoint / 4.4 X 1000
When does frost form?
When water vapor changes to ice on surfaces that are below freezing.
Stratus Clouds
Horizontal layering with a uniform base. Flat, hazy, featureless clouds varying in color from dark gray to nearly white. May produce a light drizzle or a small amount of snow. These clouds are essentially above-ground fog (below 6,000 ft.)
Stratocumulus Clouds
generally appear as a low, lumpy layer of clouds that is sometimes accompanied by weak intensity precipitation. Stratocumulus vary in color from dark gray to light gray and may appear as rounded masses, rolls, etc., with breaks of clear sky in between (below 8,000 ft) hand size
Nimbostratus Clouds
This cloud typically forms from altostratus in the middle altitude range, but it tends to thicken into the low altitude range during precipitation. Although usually dark at its base, it often appears illuminated from within to a surface observer. Is a major precipition cloud and produces virga and rain columns (below 10,000 ft)
Altostratus Clouds
a cloud of a class characterized by a generally uniform gray sheet or layer, lighter in color than nimbostratus and darker than cirrostratus: of medium altitude. It can produce light precipitation, often in the form of virga. If the precipitation increases in persistence and intensity, the altostratus cloud may thicken into nimbostratus. (8000–20,000 ft
Altocumulus Clouds
A middle-level cloud either banded or rounded in formation. Sometimes, they look like balls of cotton stuck into the blue background of the sky, while other times they look like rows. Often, these clouds have shadows or dark areas and can sometimes signal bad weather is approaching. They are made of water whereas high-level clouds are made of ice. (6,500–20,000 ft) thumb size
Cirrus Clouds
The most common form of high-level clouds are thin and often wispy cirrus clouds also known as mares tails. They form when water vapor undergoes deposition. (above 20,000 ft)
Cirrostratus Clouds
sheet-like, high-level clouds composed of ice crystals. Though cirrostratus can cover the entire sky and be up to several thousand feet thick, they are relatively transparent, as the sun or the moon can easily be seen through them. (Above 20,000 ft)
Cirrocumulus Clouds
Have distinguishing characteristics displayed in a fine layer of small cloud patches. These small cloud patches are sometimes referred to as “cloudlets” in relation to the whole cloud formation.
Are formed from ice crystals and water droplets. Often, the water droplets in the cloud freeze into ice crystals and the cloud becomes a cirrostratus cloud. They usually only form as part of a short-lived transitionary phase within an area of cirrus clouds and can also form briefly as a result of the breaking up of part of a cumulonimbus anvil. (above 20,000 ft)
Cumulus Clouds
These are fair weather cumuliform clouds of limited convection that do not grow vertically. The vertical height from base to top is generally less than the width of the cloud base. They appear similar to stratocumulus but the elements are generally more detached and less wide at the base.
Cumulonimbus Clouds
known as a thunderstorm cloud. Form in very unstable air. A heavy and dense cloud of considerable vertical extent in the form of a mountain or huge tower, often associated with heavy precipitation, lightning and thunder. The mature Cumulonimbus cloud has a distinctive flat, anvil shaped top. (6,500–60,000 ft)
