1. Weather

2. Weather vs. Climate Weather changes from day to day
One day it may be hot and dry, the next day cold, wet, and stormy
Climate is the average
weather for a particular region over a long period of time
As the saying goes, “Climate is what you expect and weather is what you get”

3. What is Weather?
The state of our atmosphere on a ___to day basis, with respect to _______and_______
Answer Bank
temperature
day
precipitation
Liquid
Absorbed
Phase
released

4. Evaporation
Water exists in our atmosphere in a solid, liquid and gas form
In order for a liquid like water to become a gas, energy must be absorbed!
If enough energy is absorbed, the molecules can escape, and enter the gas phase

5. What is Evaporation?
The cooling process by which water is converted from a liquid into a ____ (water vapor)
Energy is ____ and it is a cooling process
Answer Bank
Evaporation
gas
Continuous
Liquid
Absorbed
Phase
released

6. Condensation Think of Condensation as evaporation in reverse
If water vapor in the air cools, it will turn back into a liquid
So, Condensation is the process by which water vapor in the air is changed into liquid water

7. What is Condensation?
The process by which water vapor in the air is changed back into _____water
Energy is______
Answer Bank
Evaporation
gas
Continuous
Liquid
Absorbed
Phase
released

8. Humidity Water is in the air all around us But how much?
It all depends on how warm the air is
The warmer the air, the more moisture it can hold or contain
The cooler the air, the less water vapor it can contain

9. What is Humidity? A measure of the amount of _____in the air
Warmer air can hold more water vapor
Critical thinking: Have you ever
visited a tropical location??
Was the air humid or dry???
Answer Bank
decrease
surface
altitude
droplets
Water vapor
rises
condensation

10. The ocean absorbs radiation (heat) from the sun The Water Cycle
Water is now stored
in the atmosphere
Stored water on land flows
back to the ocean
through rivers or
groundwater
As water vapor
rises it cools,
and condenses,
turning back into
A liquid, forming
clouds
The ocean
absorbs
radiation (heat)
from the sun
Evaporation causes
water molecules
to rise
As the Clouds rise
higher, they cool,
dropping Precipitation
(snow, hail, rain)

11. What is the Water Cycle?
The _______movement of water on, above, and below the surface of the Earth through evaporation and condensation
Answer Bank
Evaporation
gas
Continuous
Liquid
Absorbed
phase

12. Summarize: ______ is the state of our atmosphere on a daily basis
_______ is when water is converted from a liquid into a gas and _______ when water vapor (gas) in the air is changed back into liquid water
Humidity is A measure of the amount of _____in the air
The ________ _________is the continuous movement of water on, above, and below the surface of the Earth through evaporation and condensation
Answer Bank
Humidity
Evaporation
Water cycle
Weather
Condensation
water

13. Topic: Dew point and clouds
Objectives:
I will know what the dew point is
I will know what a cloud is and how we classify them

14. Dew Point  At the dew point temperature
Air begins to cool at night
Eventually it will reach the Dew Point,
Temperature when condensation begins
 At the dew point temperature
Fog, clouds or dew form
Air can only hold so much moisture
At a certain temperature, the dew point, condensation begins
At the dew point temperature clouds, fog or Dew will form
Air can only hold
so much moisture

15. Dew Point Remember, humidity is the amount of water vapor in the air
When warm, saturated, humid air comes in contact with cooler surfaces, dew forms as a result of condensation
Features such as grass, leaves, and spider webs often contain dew

16. At the dew point temperature
What is the Dew Point?
The temperature air needs to cool for _______to begin
If the temperature is _____then Dew Pt., then clouds, fog or Dew will form
At the dew point temperature
Fog, clouds or dew form
Answer Bank
decrease
surface
altitude
droplets
Water vapor
rises
Condensation
below

17. Clouds
Clouds are small collections of small water droplets or ice crystals that form through condensation or freezing
Clouds can form either high in our atmosphere or near the surface

18. What is a Cloud?
A collection of small water _____ or ice crystals suspended in the air,
They form from ______when the temperature is below the_______
Answer Bank
Dew point
surface
altitude
droplets
Water vapor
rises
Condensation
below

19. Cloud Classification Clouds are classified by their shape and altitude
The 3 basic cloud types are: stratus, cumulus, and cirrus

20. Stratus Clouds
Clouds with flat bottoms that are found close to the surface
“Stratus” means sheet like or layered
Right above fog are stratus clouds

21. Cumulus Clouds Cumulus clouds resemble big fluffy cotton balls
They have a flat base that show a well-defined condensation level

22. Cirrus Clouds
Cirrus clouds have feathery appearance and are composed of ice crystals
They form at high elevations
Cirrus clouds are seen during sunny skies and are a sign that bad weather is on it’s way

23. What are the 3 types of clouds?
Stratus- low _____ clouds, with layered, sheet like shape
Cumulus-middle altitude clouds, with flat, _____shape
Cirrus- ____altitude clouds made of ____ crystals, giving them a feather like shape & associated with sunny, fair weather
Answer Bank
wedging
Ice
combination
Altitude
high
convergence
fluffy
lifting

24. Condensation Nuclei
Our atmosphere contains billions of particles of dust, pollen, ice, salt and other materials
Because these particles are so small, they remain suspended in our air
These small particles provide the “seed” needed for water to condense into water droplets

25. Condensation Nuclei Condensation nuclei are very small
Dust Particle
Condensation nuclei are very small
Water molecules are attracted the surface of these small particles
The result is a typical cloud droplet that forms by condensation
Salt
Crystal

26. Condensation Nuclei
To give you an idea of how small these particles are, we can compare the size of a rain drop and cloud droplet to the size of a condensation nuclei

27. Water Molecules love Condensation Nuclei!
Dust grain:
Condensation Nuclei

28. Condensation Nuclei Smoke particles can serve as condensation nuclei
Here, a cloud forms over a small fire

29. What are Condensation Nuclei?
A solid particle (dust, pollen, salt) in the atmosphere that provides the _____on which water vapor condenses
Answer Bank
decrease
surface
altitude
droplets
Water vapor
rises
Condensation
below

30. Summarize
____ clouds are low elevation clouds and have a flat shape to them
_____ clouds are fluffy and slightly higher than stratus clouds
______ clouds are high elevation clouds made of ice crystals
_____ _____ is the temperature at which clouds, fog, and dew forms
A ________ is collection of small water droplets or ice crystals suspended in the air
______ ______ provide a surface for water droplets to condense on
Answer Bank
Dew point
cloud
Humidity
Water vapor
rises
Cumulus
Cirrus
Stratus
Condensation nuclei

31. Summary Humidity is . . . . . Dew Point is when . . . .
A cloud is just a
Adiabatic cooling is the result of . . .

32. Topic: Cloud Foramtion
Objectives:
I will know the 4 ways clouds can form
I will understand coalescence and the 4 kinds of precipitation

33. Cloud Formation
When air rises it cools, condenses and reaches the DEW POINT temperature
Whenever humid air rises, clouds form

34. Convective Lifting Dew Point Temperature As air rises it cools!!!!!
Temperature air
needs to cool In
order for clouds,
fog & dew to form
As air rises it cools!!!!!

35. Orographic Lifting Dew Point Temperature
Mountains force air to rise, as
it rises it cools and condenses!!!!!

36. Covergence Dew Point Temperature
Temperature air
needs to cool In
order for clouds,
fog & dew to form
As air rises it cools and condenses!!!!!

37. Frontal Wedging Dew Point Temperature Warm Light Air Cold Heavy Air
Temperature air
needs to cool In
order for clouds,
fog & dew to form
Warm Light Air
Cold Heavy Air
As air rises it cools and condenses!!!!!

38. Cloud Formation
Convective Lifting - The hot surface causes the air above it to rise above the condensation level

39. What caused this band of clouds to form over the equator?

40. Frontal Wedging
Cold air lifting warm air, resulting in clouds

42. How did this cloud form? 2 ways
Convergence -2 air masses coming together
Orographic Lifting - mountains lifting air

43. What are the 4 ways clouds can form?
When air rises it cools, condenses forming water droplets
4 ways air rises:
- Orographic lifting -mountains lift air
- Frontal_____- warm air is lifted above colder air
-____________- air converges and is forced upward
- Convective______- hot air rises over hot land
Answer Bank
wedging
combination
Altitude
high
convergence
fluffy
lifting

44. Precipitation
Any moisture that falls from the air to Earth’s surface is called Precipitation
The 4 major types of precipitation are rain, snow, sleet, hail

45. What is Precipitation? Any _______ that falls from the air to Earth’s
surface is called Precipitation
4 types exist: ______,
snow, sleet, hail
Answer Bank
wedging
rain
Altitude
moisture
convergence
fluffy

46. Coalescence Ever wonder how rain drops form?
They form through a process call coalescence
A rain drop is the combination of smaller cloud droplets coming together to form a large rain droplet
As larger droplets grow, they fall picking up even more small droplets in the process
Growth of a Raindrop

47. Coalescence
How do we go from a small cloud droplet, to a typical, large raindrop

48. Gravity pulls the heavy
Coalescence
Rain Droplet
Cloud Droplets
Gravity pulls the heavy
Large raindrop down

49. What is Coalescence?
Answer Bank
wedging
Ice
combination
Altitude
high
convergence
fluffy
lifting
The formation of a large rain droplet by the ______ of smaller droplets
Growth of a Raindrop

50. Summarize
The 4 ways clouds can form are _______, ________, _________, and __________.
________ is the formation of a large rain droplet by the combination of smaller droplets
______ is any moisture that falls from the air to Earth’s
4 kinds of precipitation are _____, ______, _____ and _____

51. Topic: Fronts & High/Low Pressure
Objectives:
I will know the difference between a cold and warm front
I will understand the difference between high and low pressure systems

52. How Air Moves
If you recall, The sun drives our winds due to the uneven heating of earth
This unequal heating creates our global wind patterns
Remember, hot equatorial air moves to the cold poles by convection, resulting in our wind
Then, the Coriolis Effect causes our wind to curve and spin
But, air also moves as a result of pressure differences in our atmosphere

53. How Air Moves
Air moves from areas of high pressure (H), to areas of low pressure (L)
During High Pressure, air
sinks
During Low
Pressure,
air rises

54. High vs. Low Low Pressure High Pressure As air sinks, it
As air rises, it spins
Counter clockwise
As a result, cloudy stormy
weather forms
High Pressure
As air sinks, it
spins clockwise
As a result sunny,
clear weather forms

55. L H During High Pressure, (H) air spins clockwise as it sinks
During Low Pressure, (L) air
spins counter-clockwise as it rises L H

56. Where in the U. S. is sunny High pressure. Where in the U. S
Where in the U.S. is sunny High pressure? Where in the U.S. is stormy Low pressure? L L H H H L

57. Where is the stormy weather?

58. High vs. Low High = 1020mb Low = 990mb
Wind flows from High Pressure to Low Pressure
The greater the pressure difference, the faster the wind
High = 1020mb
Low = 990mb
Air_____, spinning clockwise creating
Sunny clear weather
Air_____, spinning counter-clockwise creating, cloudy stormy weather
Answer Bank
temperature
tropical
cumulus
funnel
Sinks
thunder
stratus
warm
moisture
rises

59. Air Masses
When air doesn’t move, it starts to take on a characteristic temperature and humidity for that region
An air mass is a large body of air throughout which temperature and moisture content are similar

60. Cold, Dry air mass
Warm Humid Air Mass

61. What is an Air Mass? 4 types exist:
A large body of air throughout which temperature and moisture content are similar
4 types exist:
-Continental – form over land
-Maritime – form over the ocean
-Tropical – Warm, humid
-Polar – Cold, Dry
Answer Bank
temperature
tropical
cumulus
funnel
Sinks
thunder
stratus
warm
moisture
rises

62. Fronts When 2 air masses meet they don’t mix, they form Fronts Why?!
Because they have different Temperatures and Densities
A cold air mass is dense and does not mix with a warm air mass
There are 2 types of fronts: Cold Front and a Warm Front

63. Cold Fronts
When a cold air mass overtakes a warm air mass, a cold front forms
The moving, heavier, cold air lifts the warm air
If the warm air is moist, Clouds will form
Large cumulus and cumulonimbus form along cold fronts
A cold front is defined as the area or zone where a cold air mass is replacing a warmer air mass

64. Cold Fronts The side with the “teeth” has the warmer air
The colder air is pushing the warmer air up

65. A Cold Front Approaching: Notice the large cumulus clouds

66. Warm Fronts
When a cold air mass retreats from an area, a warm front forms
This warmer, lighter, less dense air rises over the cooler air
A warm from has a gradual slope, with clouds that form as the warm air rises along the front
A warm front can cause rain, and even sever thunderstorms
A warm front is defined as the area or zone where a warm air mass is replacing a cold air mass

67. Warm Front
On a weather map, Colder temperatures are on the side of the semi circles

68. Where is the warm front? Where is the cold front?

69. What is the difference between Cold Front and Warm Front?
A cold front is when a cold air mass is ______ a warmer air mass and ______ Clouds form as warm air is forced upward
A warm front is an area where a ____ air mass is replacing a cold air mass and _______ clouds form as warm air is forced upward
Answer Bank
replacing
tropical
cumulus
funnel
Sinks
thunder
stratus
warm
moisture
rises

70. Severe Weather
Severe weather is any weather that may cause property damage or loss of life
Severe weather may include large quantities of rain, lightning or hail, strong winds, or tornadoes
Severe weather causes billions of dollars in damage each year

71. Thunderstorms
A thunderstorm is accompanied by rain, thunder, lightning, and strong winds
A thunderstorm is an extreme low pressure system

72. What is a Thunderstorm?
A brief heavy storm (low pressure) that consists of rain, strong winds, lightning, and________
Answer Bank
temperature
tropical
cumulus
funnel
Sinks
thunder
stratus
warm
moisture
rises

73. Tornadoes
A tornado is the most violent, and shortest lived severe storm or low pressure system
It is basically a destructive rotating column of air that has very high winds producing a funnel shaped cloud

74. Tornadoes
The winds of a tornado may reach speed of over 400 kilometers!
Usually everything in a tornado’s path is destroyed

75. Tornado Formation
Cold, dry
air mass from
Canada
A tornado is the result of warm tropical air coming up from the gulf of Mexico meeting cold dry air coming down from Canada
Warm, humid
air mass from
Gulf of Mexico

76. What is a Tornado?
A destructive, rotating column of air that has very high wind speeds and that maybe visible as a funnel shaped cloud
Tornadoes form when a cold dry, polar air mass from Canada meets warm, wet tropical air mass from the Gulf of Mexico
Answer Bank
temperature
tropical
cumulus
funnel
Sinks
thunder
stratus
warm
moisture
rises

77. Hurricanes A hurricane is a tropical storm
Hurricanes do not have warm and cold fronts
Hurricanes develop over warm tropical water where evaporation & condensation release a tremendous amount of heat (latent heat)

78. Hurricanes
Hurricanes are about 700 kilometers in diameter and can have winds that can reach up to 275 kilometers an hour along the eye wall
Hurricanes are the most destructive storms on earth

79. temperatures cause massive amounts of evaporation
Hurricanes form of
the coast of Africa
where warm ocean
temperatures cause massive
amounts of evaporation
The trade winds blow the
hurricane toward the gulf
of Mexico & the United States

80. What is a Hurricane?
A severe storm that develops over _____ oceans and whose strong winds of over 120 km/h spiral in toward the low-pressure storm center
Answer Bank
temperature
tropical
cumulus
funnel
Sinks
thunder
stratus
warm
moisture
rises

81. Summarize
A _____ ______ is when a cold air mass is replacing a warmer air mass and ______ Clouds form
A _____ ______ is an area where a warm air mass is replacing a cold air mass and _____ clouds form
Wind flows from _____ Pressure to ____ Pressure
The greater the pressure difference, the ______ the wind
High pressure systems spin_____ and low pressure systems spin ______
Answer Bank
cumulus
Cold
low
clockwise
Counter-clockwise
Warm
Faster
high
stratus