Weather• Describes the current condition of the atmosphere.

Factors include- _____________________ cloud cover, ___________________ & direction, humidity, and __________________________

• Temperature- Measures how ____________ air molecules are moving Rapid-______/slow-___________ Use a ______________________ to measure

• Atmospheric Pressure Air has ________________, and the weight exerts ___________ When air is heated molecules move ________ and air expands, making air less dense. This is

why it is moved _______________(convection current) Warm ______________/cool _______________ Use a __________________________ to measure

• Energy Transfer Fast moving molecules transfers to slow moving, transfer of energy when molecules collide

is ___________________________ Warm air rising cool air sinking is ______________________ (main way heat is transferred

in atmosphere)

• Humidity- amount of ________________________ in the atmosphere ______________________ more evaporation occurs thus more water vapor ___________________- temperature at which condensation can occur. when the air is

saturated (holds all the vapor it can) condensation can occur Measured with ________________________________or hygrometer

• Clouds A _____________ is a large collection of very tiny droplets of water or ice crystals.

The droplets are so small and light that they can float in the air.

1

Low clouds Stratus Nimbostratus Cumulonimbus Stratocumulus Cumulus

Middle Clouds Altocumulus Altostratus

High and vertical clouds Cirrus Cirrocumulus Cirrostratus

• Winds Wind is the ___________________movement of air from___________ to low pressures. Described by their direction and their __________. Name tells you where it is

___________________________.o Measuring Wind-

Direction is measured by ___________________________ An _____________________ measures wind speed. The cups catch the wind, turning a dial

attached to the instrument. The dial shows the wind speed.

Air Masses

• Air masses move due to ___________________• _______ (continental) or _________ (maritime) and ___________(tropical) or _________(polar),

depending on where it _______________. • Mass of air that remains over a region for a few days and takes on the characteristics of the area

it occurs• When air masses of different temperature meet, a boundary is formed called a ______________• A large body of air with similar ______________________and ______________________.• Air masses form over large _______________ or ______________ masses and are named by

where the form…over land-continental or over water-maritime and also named for where they originate from-near the tropic-tropical and from near the poles-polar

• Dry (continental)- comes from ____________ masses• Humid (maritime)- comes from __________________• Warm (tropical)- __________________ coming up from the equator• Cold (polar)- __________________ coming down from the poles

2

Pg 598 in book is reference

– Continental polar (cP)- ______________ and _________________– Continental arctic-type of continental polar mass that is much colder-forms in the arctic

circle– Continental tropical (cT)- _____________ and ________– Maritime polar (mP)- _________(wet) and ___________unstable– Maritime tropical (mT)- ___________ (wet) and _________ unstable

Fronts• Cold-

– ___________ air pushes under warm air pushing it up,– Cumulus & cumulonimbus brings – Narrow band of _______________________ can occur (short period of heavy precip.) – cold air in (temp drops)– Cold fronts move __________________than warm fronts. – The weather activity in a cold front is often ________________and happens directly at

the front.– Cold fronts have sudden ____________________ high in the air creating

________________. – Shown on a weather map by a ____________ line with _____________ pointing the

direction in which the cool air (front) is moving.

–

• Warm-

– ___________ dense (warm) slides _______________________ cold air;– high _____________ clouds first and then stratus– Long periods of _________________ precip.

3

– ________________ air in Temperature ___________________– The weather activity in a _______________ front generally happens before the front

__________________________________________. – In a warm front the _____________________________ is very low often creating

situations of poor ________________________.– Shown on a weather map by a ______________line with ____________________

pointing the direction in which the warm air (front) is moving.

• Stationary

• _______________air & cold air meet and neither advances

• Remains in _______________location for days

• Cloudiness and ______________________ may occur

• Occluded

• When a _______________ front is trapped by ________________________________ fronts.

• Shown on a weather map by a _________________ with alternating _______________ and __________________ pointing the direction the front is moving.

• may produce ______________________ with precipitation

4

High and Low Pressures

Air Pressure Moves from _______________ to_______________ areas

• High pressure areas air ___________________– Moves from ________________ to low– Air moves ________________ due to Coriolis– Usually _________________ with few clouds– High air pressure is associated with ___________________ which means sunny and fair

weather.• Low pressure area- air ________________and ______________

– Air circulates in _________________________– Air reaches _________________ water vapor condenses forming clouds and

____________________________– Low pressure is associated with ___________ fronts which means cloudy, overcast,

drizzly, and possibly _______________________.

Cyclones

• ___________________- swirling center of low air pressure• Warm air at the center _______________and air pressure ____________. Cooler air blows from

areas nearby.• Spins ____________________ in Northern Hemisphere

Anticyclones

• Central __________________ is _______________ than that of its surroundings • Winds spiral _______________ from centers of dry air• Spin ____________________ in Northern Hemisphere

5

Severe Weather

• ___________________________- cumulonimbus clouds (along __________ fronts)

– ________________- energy flow that occurs between areas of opposite electrical

charge

Thunder

• Lightning is 5-6 times hotter than sun’s surface (54,000 degrees Fahrenheit.) -causes air to

_____________ quickly, then cools quickly and contracts producing rapid movement of

molecules

• Sound due to expansion and ______________ of the heated air

Lightning

• Lightning happens when the ________________ charges (electrons) in the bottom of the cloud

(and your finger) are attracted to the ___________________ charges (protons) in the ground.

• The accumulation of electric charges has to be great enough to overcome the insulating

properties of air. When this happens, a stream of negative charges pours down towards a high

point where positive charges have clustered due to the pull of the thunderhead.

6

• The connection is made and the protons rush up to meet the electrons. It is at that point that we

see lightning. A bolt of lightning heats the air along its path causing it to expand rapidly. Thunder

is the sound caused by rapidly expanding air.

Tornadoes

• A tornado is a violent ______________column of air extending from a thunderstorm to the

ground.

• The most violent tornadoes are capable of tremendous destruction with wind speeds of up to

300 mph.

• They can destroy large buildings, uproot trees and hurl vehicles hundreds of yards. They can also

drive straw into trees. Damage paths can be in excess of one mile wide to 50 miles long. In an

average year, 1000 tornadoes are reported nationwide.

How Do They Form?

• Most tornadoes form from _______________________; last ______________ period of time

(minutes)

• You need ____________, __________________ air from the Gulf of Mexico and

______________, _________ air from Canada. When these two air masses meet, they create

_________________ in the atmosphere.

• A change in wind direction and an increase in wind speed with increasing height creates an

invisible, horizontal spinning effect in the lower atmosphere.

•

7

• Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of

rotation, 2-6 miles wide, now extends through much of the storm.

•

What is a Hurricane?

• A _______________________ is a huge storm!

• It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of

75 to 200 mph.

• Each hurricane usually lasts for _______________________, moving 10-20 miles per hour over

the open ocean.

8

Atmosphere

• The envelope of _____________ that surround the planet. • a buffer that keeps us from being peppered by ______________________, • a screen against deadly ______________, and the reason radio waves can be bounced for long

distances around the planet.• It is roughly

• 78% _______ (N2), (Nitrogen is "fixed" from the atmosphere by bacteria in the roots of certain plants-nitrogen cycle)

• 21% _________(O2), with trace amounts of _______ (H2O), argon (Ar), carbon dioxide (CO2) and other gases.

• Nowhere else in the solar system can one find an atmosphere loaded with free oxygen• Levels

• Troposphere-• Stratosphere• Mesosphere• Thermosphere• Exosphere

9