Download Chapter 2 – Understanding Weather SECTION 1 - HUMIDITY

Chapter 2 – Understanding Weather
SECTION 1 - HUMIDITY
____________________ - the amount of water vapor in air
Air’s ability to hold water vapor changes as the __________________ of the air changes.

Increased temperature means the air can hold_______________________ water.

Decreased temperature means the air can hold ______________________ water.
Relative Humidity: ratio of __________________ in the air to the ________________
amount the air can old.
2 factors that affect relative humidity:
1. ________________________
2. ________________________
_________________- tool to measure relative humidity; contains a wet bulb & a dry bulb.

The difference in temperature readings_____________________________ = the
amount of water in the air.
Dew Point-___________________________________________________________
Happens when relative humidity = ________%
SECTION 2: CLOUDS
2 steps to cloud formation:
1. _______________________________________________
2. Air cools and condenses, forming ______________________
Clouds are made of:
1. Ice crystals – when water condenses ____________________________
2. Water droplets – when water condenses _________________________
Clouds are classified by:
1. ____________________________
a. _______________________
b. _______________________
c. _______________________
2. ____________________________
a. _______________________
b. _______________________
c. _______________________

Nimbo or Nimbus = clouds producing
.
LOW CLOUDS
Low clouds – found below __________ meters and made of only
.
Description
Stratus
Nimbostratus
Stratocumulus
MIDDLE CLOUDS
Middle clouds – found between __________ meters and ___________ meters.
They are made of ____________________ or _____________________

- indicates most middle clouds
Description
Cumulus
Cumulonimbus
Altocumulus
Altostratus
HIGH CLOUDS
High clouds – found above ____________ meters. Temperature is very
made of ______________________.
Description
Cirrus
Cirrocumulus
Cirrostratus
and
SECTION 3 -FRONTS

__________________- a very large volume of air that has a certain temperature
and moisture content

_________________ - the place where 2 or more air masses meet
o The __________dense air mass rises over the __________ dense air mass.
4 Types of Fronts:
What’s happening
Cold
- Cold air mass moves
- Cold air mass
-Moves quick & brings
Warm
a warm air mass and
warm air mass.
precipitation
.
air mass moves in over a cold air mass leaving an area.
- Warm air mass
cold air mass as it moves away.
- Brings
rain followed by clear & warm weather.
Occluded
air mass is caught between
-Bring cold temperatures, rain, & snow
.cold air masses
Stationary - Cold air mass & warm air mass move toward
.
- Neither has enough
to push the other away.
- Remain in same place causing cloudy weather
____________________ - air mass formed that has lower pressure than surrounding air
-
Air rises and cools
-
Forecast: Clouds can form & cause
or
weather.
_____________________ - air mass that has higher pressure than surrounding air.
-
Air sinks and gets warmer. Relative humidity
-
Forecast: Warm sinking air brings
.
,
•
Watch – event is likely to __________________
•
Warning – event has been
and it is
weather
.
THUNDERSTORMS: 4 steps to the formation
1. Body of ______________ air is found above body of ______________ air.
2. ________ air rises and cools as it mixes with _____________ air.
3. When warm air reaches its
and forms
, water vapor
clouds.
4. If warm air keeps rising, clouds may become dark
clouds.
LIGNTNING: 3 steps to the formation
1. As a cloud grows ____________, parts of it begin to develop electrical ________.
•
Upper parts =
charged & Lower parts =
2. When one charge gets big enough,
another or the
charged
flows from one area
.
3. These electrical currents are
.
THUNDER: 4 steps to the formation
1.
moves through the air.
2. The air gets very hot and ________________rapidly.
3. As it expands, it makes air
.
4. These vibrations release energy in the form of sound waves called _____________
HURRICANE: 5 steps in formation
1. Begins as a group of __________________traveling over tropical ocean waters.
2. Winds traveling in two different directions meet and cause the storm to spin –
.
•
__________________in the North and _________________in the South
3. A group of thunderstorms form & produce a large, spinning storm –
.
4. Storm picks up strength as it travels over _________ water 
.
5. When they move over cold water or land they
•
Hurricanes are also called __________ in the Pacific Ocean and __________ in the
Southwest Indian Ocean.
________________________- a rise in sea level that happens during a storm
Tornadoes – rapidly whirling, funnel shaped cloud. Wind speeds may reach _____ mph.
•
Direction of tornadoes = __________________________.
TORNADOES: 4 steps to the formation
1. Wind moving in 2 ________________causes a layer of air in the middle to begin to
___________ like a roll of toilet paper.
2. The spinning column of air is turned to a __________________position by strong
updrafts of air in the cumulonimbus cloud. The updrafts of air also begin to spin.
3. The spinning column of air moves to the _________________of the cumulonimbus
cloud and forms a ________________________.
4. The funnel cloud becomes a tornado when it ________________________.
•
Tornado Alley: Located between _____________&__________________________.