W02 Clouds and Meteors Flashcards
Define Cloud
A Hydrometeor consisting of minute particles of liquid water or ice, or of both suspended, in the free air and usually not touching the ground.
Define Layer Cloud, andWhat cloud form is a layer cloud?
A cloud which generally has significant horizontal extent but not great vertical extent.Stratiform
What type of precipitation (continuous, showery, or intermittent) could come from layer clouds?
Could be either continuous or intermittent
How much turbulence and/or icing would usually be associated with a layer cloud?
Ranges from None to Moderate
Define Vertical Development Cloud, andWhat cloud form is a vertical development cloud?
A cloud which has moderate or great vertical extent.Cumuliform
How much turbulence and/or icing would be usually be associated with a vertical development cloud?
Moderate to Severe
What type of precipitation (continuous, showery, or intermittent) could come from cumuliform clouds?
Showery
What are the 3 basic cloud forms?
StratiformCumuliformCirriform
Define Stratiform Cloud
Clouds composed of rolls or elements, sometimes uniform in structure and normally stretched out in layers.
Define Cumuliform Cloud
Clouds which are composed of individual elements or bases and tend to have large vertical extent.
Define Cirriform Cloud
Clouds which are found in the upper portions of the sky and are ALWAYS composed of ice crystals
Clouds other than cirriform clouds may be composed of ____________________________
ice crystals, water droplets, or a combination of both.
What is the height range for the low etage?
near sfc to 6500 ft
What is the height range for the middle (Alto) etage?
6600 to 19000 ft
What is the height range for the high etage?
20000 feet & abv
List the 14 cloud types reported in Canadian hourly wx reports. Name AND abbreviation.
Stratus Fractus - SFStratus - STNimbostratus - NSStratocumulus - SCCumulus Fractus - CFCumulus - CUTowering Cumulus - TCUCumulonimbus - CBAltostratus - ASAltocumulus - ACAltocumulus Castellanus - ACCCirrus - CICirrostratus - CSCirrocumulus - CC
Which of the 14 cloud types belong to the LOW etage? (Answer written in abbreviations)
SF, ST, NS, SC, CF, CU, TCU, CB
Which of the 14 cloud types belong to the MIDDLE etage? (Answer written in abbreviations
AS, AC, ACC
Which of the 14 cloud types belong to the HIGH etage? (Answer written in abbreviations
CI, CS, CC
Define “Nimbus” / “Nimbo”
Giving or capable of giving precipitation
Define “Alto”
In the middle levels
Define “Fractus”
Broken up, Fragments
Define “Towering” or “Congestus”
Vertical Development
Define “Castellanus”
Turrets or Towers
Define “Floccus”
small cumuliform tufts, lower part ragged
Define “Lenticular”
Almond/lens/cigar shaped
Define “Mamma”
Pouchy, breast-like hangings on the underside of a cloud
Define “Virga”
Precipitation not reaching the ground
Describe Stratus Fractus
Grey colour cloud with diffuse irregular shreds.Near sfc to 1500 ft - usually very low100 to 1000 feet thickComposed of Water droplets, ice crystals, and super-cooled water dropletsNo precipitation
Describe Stratus
Light to medium grey colour uniform layer. Resembles fog, but not resting on sfc. Gives the sky a hazy appearance. Often has a ragged base. Near sfc to 1500 ft - usually in lower levels100 to 3000 feet thickComposed of Water droplets, ice crystals, and super-cooled water dropletsDrizzle, Freezing Drizzle, Snow Grains, Snow
Describe Nimbostratus
Very dense in a low diffuse rainy layer. Medium to dark grey in colour. Usually nearly uniform (little elementing), may be ragged. Feebly illuminated, seemingly from inside. Diffuse wet-looking base. Generally have SF or ST forming below in precipitation.Near sfc to 6500 Ft, usually below 5000 ft.4000 to 20000 feetComposed of Water droplets, ice crystals, and super-cooled water droplets - usually top portions are ice crystals.Rain, Snow, Ice Pellets, Freezing Rain
Describe Stratocumulus
Layer of patches of globular masses or rolls, with fairly large elements. Soft and grey with darker parts. Elements arranged in groups, lines, or waves, aligned in one or two directions.Near sfc to 6500 feetUp to 3000 feet thickWater droplets and/or ice crystals, supercooled water droplets, mixture of water droplets and ice crystals RARE in SC. Usually no precipitation. If any, light snow, light rain, light snow pellets if vertical development cloud embedded.
Describe Cumulus Fractus
White to light grey colour with dense centres. Ragged edges show constant change. Rounded shape, lacking the flat bases of CU. Appears white in the sun, and dark in bad weather.Near sfc up to 2000 feet. Bad weather = usually very lowSmall vertical extent, usually no more than 500ftwater droplets.Nil precipitation.Often forms below NS in precipitation.
Stratus Fractus abbreviation
SF
Stratus abbreviation
ST
Nimbostratus abbreviation
NS
Stratocumulus abbreviation
SC
Cumulus Fractus abbreviation
CF
Cumulus abbreviation
CU
Towering Cumulus abbreviation
TCU
Cumulonimbus abbreviation
CB
Altostratus abbreviation
AS
Altocumulus abbreviation
AC
Altocumulus Castellanus abbreviation
ACC
Cirrus abbreviation
CI
Cirrostratus abbreviation
CS
Cirrocumulus abbreviation
CC
Describe Cumulus
Dense clouds appearing white in the sun, but dark central portions overhead. Flat bases and rounded tops. Individual bases.1000 to 6500 feet. Note that bases can be much higher in the summer and can become progressively higher as the afternoon goes on.500 to 5000 feet thickWater droplets, occasionally supercooledForms in the morning and dissipates in the evening-SHSN or -SHRA
Describe Towering Cumulus
Dense clouds that appear white in the sun but dark overhead with flat bases. Considerable vertical development with a hard “cauliflower” outline1500 to 6500 feet bases that can be much higher in summer.5000 to 20000 feet thickWater droplets, supercooled water droplets, ice crystalsSHRA, SHSN, SHPL, SN (snow pellets)Distinguished from cumulus by heavy active tops or towers, and from cumulonimbus by absence of ice crystal structure of top.
Give the physical description of SF
Grey colour, diffuse irregular shreds
How high is SF usually found?
It is usually very low, near the surface up to 1500 feet.
How thick is SF?
100-1000 feet thick?
What is SF composed of?
Water dropletsIce crystalsSuper-cooled water droplets
How is SF formed?
-The breaking up of stratus-formed in precipitation below AS or NS-the lifting and breaking up of fog-orographic lifting
What kind of precipitation is produced by SF?
None
Describe Cumulonimbus
Dark grey (almost black) from below. Very dense water portions. Cirriform head fairly diffuse, but more dense than most cirriform cloud. Turbulent with strong vertical currents resulting in great vertical developments. Upper parts are fibrous frequently in the form of an anvil. Base often very ragged and can be confused with NS. 1500 to 6500 feet10000 to 40000 feet thick or greater3 distinct regions - water droplets in lower portions, supercooled water droplets and ice crystals in middle levels (above freezing level), and ice crystals in the upper levels.SHRA, SHSN, GR (hail), Snow Pellets, Ice Pellet Showers, Can produce VIOLENT showersLTNG (LTGCG, LTGCC, LTGIC) , Thunder, SVR TURB, LLWS, Microburst
Describe
TBA
What are the characteristics of ST?
A uniform layer that is light to medium grey. It resembles fog but doesn’t rest on the surface. It gives the sky a hazy appearance and often has a ragged base.
What height is ST usually at?
Near the surface to 1500ft
How thick can ST be?
100-3000 feet thick
What is ST composed of?
Water dropletsSuper cooled water dropletsIce crystals
How does ST form?
-May form from SC-May be formed by a for layer lifting-orographic lifting-In precipitation-by merging of SF
What kind of precipitation does ST produce?
Drizzle or freezing drizzleSnow grainsSnow