Weather
EP.p2X B,C,D,E,G,H
WATER IN THE AIR
DO NOW
What is the difference between Weather and
Climate?
-Weather is the condition of the atmosphere at
a particular time.
-Climate is weather over long periods of time
Humidity
• Humidity- amount of water in the air
– Warmer air holds more water vapor
• Relative Humidity- amount of moisture in the
air compared to (Divided By) how much the
air can hold
• EXAMPLE: Say the air can hold 24G’s of
moisture, but only has 18G’s. What the
relative humidity?
• Answer- 75%. 18G/24G = .75
– Humidity/ Maximum Possible Humidity
• Psychrometer- device that measures relative
humidity
• Relative Humidity can be affected by:
– Rates of evaporation (Water vapor in the air)
– Temperature
Process of Condensation
• Condensation- gas become liquid
– Before condensation can occur, relative humidity
must be at 100%
• Saturated- relative humidity at 100%
• Dew Point- temp at which water vapor
condenses
What’s the Difference?
• Dew- when water vapor condenses on a given
surface
• Fog-cloud with ground surface contact
• Clouds- moist air and particles rise quickly,
cool, and condense
Assignment Day 1
• 1. What is the difference between relative
humidity and humidity?
• 2. What are the two ways relative humidity
can be affected?
• 3. What does relative humidity at 75% mean?
• Calculate The Relative Humidity:
– 4. Possibly Humidity-64G, Current Humidity-16G
– 5. Possible Humidty-96G, Current Humidity 24G
AIR MASSES AND FRONTS
Types of Clouds
• Cumulus
– Puffy, white, mid-level clouds
• Stratus
– Thin, long-layered, low-level clouds
• Cirrus
– Feathery white clouds at high altitudes
Prefixes for Clouds
• Add these to the front of the cloud types for a
new cloud formation
– Strato- low level clouds
– Alto- mid level clouds
– Cirro- high clouds
– Nimbo/Nimbus- storm cloud
• Air Mass- large body of air with similar temp
and moisture
– Cold masses bring cold weather, Warm masses
bring warm weather
• Front- boundary formed between two
different air masses
– Four types
• Cold Front- cold mass meets and pushes warm
air masses up
• Warm Front- warm air mass meets and moves
over top of a cold air mass (brings precip)
• Occluded Front- fast moving cold mass over takes
a slow warm front and slight warmer cold front,
pushing them upward (Lots of Precip)
• Stationary Front- cold air mass and a warm air
mass meet. Neither move up or down
Assignment Day 2
• 1. What is the relationship between air
masses and front?
• 2. What are the four types of fronts?
• 3.What kind of front occurs when two masses
meet and neither overtakes the other?
• 4. What kind of front occurs when warm air
meets cold air and overtakes it?
• 5. What kind of front occurs when cold air
over takes two masses at once?
FORECASTING WEATHER
Technology
• Thermometer- measures temp
• Barometer- measures air pressure 
• Wind Vane/Sock- measures wind direction
• Anemometer- measures wind speed 
Eyes in the Sky
• Weather balloons carry forecasting equipment
as high as 30km
– Temp, pressure, humidity
• Radar is used to find location, movement,
intensity of precip
Weather symbols
used on
Weather Maps
• Isobars- lines on weather map that connect
areas of equal pressure
Assignment Day 3
• 1. What are at least three tools for collecting
weather data?
• 2. How high can weather balloons travel?
• 3. For what reasons would you use radar?
• 4. How to isobars help when reading a
weather map?
• 5. Why would meteorologists compare new
maps with ones 24hrs old?
– (what could they be monitoring?)
REASON FOR THE SEASONS
What are the reasons for the seasons?
DO NOW:
• Give a guess as what you think are the reasons
for the seasons here on Earth?
The seasons are caused as the Earth, tilted on its
axis, travels in a loop around the Sun each year.
Summers happens in the hemisphere tilted towards
the sun, and Winter happens in the hemisphere
tilted away.
• Bill Nye-Seasons
SEVERE WEATHER