Fogged up windows and bad hair days are caused by humidity in the air. Water vapor condenses as clouds, dew, frost or fog depending on temperature. Clouds form through various processes and can be classified into categories like stratus, cumulus or cirrus clouds based on their shape and altitude. Air masses and fronts influence weather patterns as different air masses collide and interact.

1. WATER IN THE
ATMOSPHERE

2. WHAT DO FOGGED-UP WINDOW ON A
COLD WINTER MORNING AND A BAD HAIR
DAY IN COMMON?

3. HUMIDITY
• The amount of water vapor in the air.
• Warm, tropical air tends to contain more
water vapor than cold, polar air does.
RELATIVE HUMIDITY
-is the ratio of the amount of water vapor in
the air to the maximum amount of water
vapor that can exist at that temperature.
-when relative humidity reaches 100%, AIR
IS SAID TO BE SATURATED.

4. RELATIVE HUMIDITY
The maximum amount of water that can
exist as a gas is greater at high
temperature than at low temperature.
Ex: After sunset, the temperature often
decreases, and so the maximum amount of
water vapor that the atmosphere can hold
also decreases.

5. Dew point
• The temperature at which air becomes
saturated.
• If the temperature drops further, water
vapor will condense.
WATER VAPOR TYPICALLY CONDENSES
AS:
1. DEW 3. CLOUDS OR FOG
2. FROST

6. 1. DEW
- Is water vapor that
condenses on Earth’s
surface.
2. FROST
- Forms when the dew
point of air is below
freezing.
- Is formed when water
vapor in air changes
directly from a gas to
solid crystals.

7. CLOUDS

8. CLOUDS FORMATION
CLOUD – is a dense, visible mass of tiny
water droplets or ice crystals that are
suspended in the atmosphere.
 CLOUDS FORM as warm, moist air rises
and water vapor condenses in the
atmosphere

9. CLOUDS FORMATION

10. CLASSIFYING CLOUDS
• THREE BASIC CLOUD FORMS:
1. Stratus
2. Cumulus
3. Cirrus

11. CLASSIFYING CLOUDS
1. STRATUS CLOUDS
- Comes from Latin
word meaning “to
spread out”
Nimbo- or Nimbus-
-is added to a cloud’s
name, it means that the
cloud produces
precipitation.
Ex. Nimbostratus
clouds
Alto-
-is added to a cloud’s
name, it means middle-
level clouds.
• Altostratus clouds

12. CLASSIFYING CLOUDS
2. CUMULUS
CLOUDS
-come from Latin
for “heap”
-fair-weather clouds
3. CIRRUS CLOUD
- Thin, white, wispy
clouds, often with
a feathery or veil-
like appearance.
Cirros-
-is used to
described high-
altitude clouds

13. CLASSIFYING CLOUDS

14. FOG
-is a cloud that is near or touching
the ground.
-it often form when warm, moist air
passes over land.

15. FORMS OF PRECIPITATION
PRECIPITATION – occurs when water
droplets or ice crystals in clouds join
together and become large enough to
fall to the ground without evaporating.

16. THE MOST COMMON
TYPES OF PRECIPITATION:
RAIN SNOW
SLEET HAIL
FREEZING RAIN

17. WEATHER
PATTERNS

18. Air Masses
It is a large body of air that
has fairly uniform physical
properties.

19. Characteristics of
Air Mass
1. Air mass must be large in size
2. Air mass must have a uniform
and consistent makeup at all
points within the air mass.
3. Air mass must be physically
bound together, traveling across
the atmosphere as a single unit.

20. HOW DO AIR MASSES
FORM?
It forms when a large body of air
becomes fairly stationary over a
region of Earth’s surface or as air
moves over a large, uniform region.

22. MaritimePolar
Arctic
ContinentalPolar
ContinentalTropical
MaritimeTropical

23. CLASSIFICATION OF
AIR MASSES
1. MARITIME AIR MASS - forms over water
2. CONTINENTAL AIR MASS – forms over land
3. POLAR AIR MASS – forms North of 50º or
South of 50º, where it is often extremely
cold.
4. TROPICAL AIR MASS – originates in the
tropics, where it is warm.

24. AIR MASSES THAT MOST AFFECT
WEATHER
• MARITIME POLAR –cold and moist, and often
bring heavy precipitation to coastal areas.
• CONTINENTAL POLAR – bring cold and dry
air .
• MARITIME TROPICAL – bring warm, moist air
and are often accompanied by fog or rain.
• CONTINENTAL TROPICAL – bring hot, dry air.

25. FRONTS
The sharply
defined
boundary that
forms when
two unlike air
masses meet.

26. TYPES OF FRONTS

27. Stationary front
• When two unlike air
masses have
formed a boundary
but neither is
moving front.
• Often result in
clouds and steady
rain or snow for
several days.

28. COLD FRONT
Occurs when a cold air
mass overtakes a warm
air mass.
cumulus and
cumulonimbus clouds
Strong winds, severe
thunderstorms and hail.

29. Warm Front
Occurs when a
warm air mass
overtakes a cold
air mass.
Steady rain,
heavy showers
or
thunderstorms.

30. OCCLUDED FRONT
when a warm air
mass is caught
between two cooler
air masses.