2. Adiabatic temperatures changes and
expansion and cooling
• When air is cool it expands and when air is warm it
compresses
• The rate of cooling or heating of unsaturated air is
called dry adiabatic rate
• The wet adiabatic rate is the slower rate of cooling
when latent heat is added
http://hyperphysics.phy-
astr.gsu.edu/hbase/thermo/a
diab.html
3. Orographic lifting
• Orographic lifting is when air flow is blocked
• Many of the rainiest places on Earth are on the
windward side of mountain slopes
• When air reaches the leeward side of a mountain
the air has lost much of its moisture
http://05lovesgeog
raphy.blogspot.co
m/2011/04/types-
of-rainfall.html
4. Frontal Wedging
• In central America when masses of warm
air and cool air collide it produce a front
• Warmer air is less dense and raises
• Colder air is more dense and produces a
barrier over warmer air
http://www.erh.noaa.gov/rnk/N
ewsletter/Spring_2008/climate.
htm
5. Convergence
• Convergence occurs when air in the lower
atmosphere flows together
• Air flowing from more then one direction goes up
• The Florida Peninsula is an example of
convergence
http://apollo.lsc.vsc.edu/classes/met
130/notes/chapter6/lift_converge.ht
ml
6. Localized Convective Lifting
• Unequal heating of Earth causes rising parcels of
warmer air called thermals
• Localized convective lifting is the process that
produces rising thermals
• Pockets of air that are warmer then surrounding
air are less dense will move upward
https://www.meted.ucar.edu/sign_in.php?go_
back_to=http%253A%252F%252Fwww.meted.
ucar.edu%252Fnorlat%252Fsnow%252Flake_ef
fect%252Fprint_whole.htm
7. Stability
• The temperatures of that
atmosphere at various
heights determines the air
stability
• Stable air produces clouds
that are widespread, have
little vertical thickness
compared to their
horizontal dimension, and
precipitation is light to
moderate, if any
• Stable air resists vertical
movement and air stays in
its positions and unstable
air rises
http://keithrogershome.com/Chap6Stab
ilityInstability.html
8. Condensation
• The air must be saturated
for condensation to
occur(water vapor changes
to liquid)
• Condensation nuclei are
the surface for water vapor
condensation in the air
• Their must be a surface for
condensation to occur
http://keep3.sjfc.edu/students/kes008
98/e-
port/condensation%20page%20for%2
0unit.html
9. Types of clouds
• The three basic forms
of clouds are cirrus,
cumulus, and stratus
• All clouds show
properties of one of
the three basic cloud
forms or a mixture of
them
• Clouds are classified
on their height and
form
http://eo.ucar.edu/webweather/cloud3.html
10. High Clouds
• High clouds are made
up of cirrus,
cirrostratus,
cirrocumulus clouds
• High clouds are thin
and white
• High clouds are not
considered
precipitation makers
http://ww2010.atmos.uiuc.edu/(Gh)
/guides/mtr/cld/cldtyp/hgh/crs.rxml
11. Middle clouds
• Middle clouds are
2000 to 6000 meter
high
• Have the prefix alto
as part of their name
• Altocumulus clouds
are larger and denser
then cirrocumulus
clouds
http://www.ifimages.com/public/im
age/139051/view.html
12. Low Clouds
• Low clouds are made
up of stratus,
stratocumulus, and
nimbostratus clouds
• Stratus clouds mostly
cover much of the sky
• Nimbostratus clouds
come from a Latin
word that means rainy
cloud
http://www.cepolina.com/photo/str
atus_cumulus.htm
13. Clouds of vertical Development
• Clouds that don’t fit into the three height
ranges are associated with unstable air
• When a upward motion is triggered it will
produce clouds with vertical form
http://www.free-
online-private-pilot-
ground-
school.com/Aviation
-Weather-
Principles.html
14. Fog (by cooling and by evaporation)
• Fog can be caused by
cooling or evaporation
• Fog is produced when
warm air moves over
cold air
• When cool air moves
over warm air it
condenses and rising
making fog that looks
like steam
http://photoshoptutorials.ws/photoshop-
tutorials/photo-effects/fog.html
15. Cold Cloud Precipitation
• Formed by the
Bergeron process
• Supercooled water is
when water is in a
liquid state and below
0 degrees Celsius
• Supersaturated air has
100% saturated air for
water and above 100%
saturated for ice
http://www.srh.noaa.gov/lzk/?n=mar
2011.htm
16. Warm Cloud Precipitation
• The collision-
coalescence process
forms rain drops in
warm clouds
• Larger droplets join
together with smaller
droplets as they move
through the cloud
https://www.meted.ucar.edu/sign_in.p
hp?go_back_to=http%253A%252F%252
Fwww.meted.ucar.edu%252Ftropical%2
52Ftextbook_2nd_edition%252Fprint_5
.htm
17. Rain and snow
• Rain is a drop of water
that falls from a cloud
and has a diameter of .5
mm
• Light snow occurs when
there is a small amount
of water vapor in the air
• Heavy snow occurs when
temperatures are warmer
than -5 degrees Celsius
http://www.mapsofworld.com/world-
maps/precipitation-rain-and-snow-
enlarge-map.html
18. Sleet, Glaze and Hail
• Small particles of
clear ice are called
sleet
• Freezing rain is
commonly known as
glaze
• Cumulonimbus
clouds produce hail
http://www.theweatherprediction.com/severe
/gianthail/
