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Winds, Air Masses, and Fronts Note Guide
1) What are winds?
a) A wind is the horizontal movement of air from an area of __________ pressure to an area of ___________
pressure.
b) _____________ are caused by differences in air pressure.
2) Convection Currents
a) Form when an area of Earth’s surface is _____________________ by the sun’s rays.
b) Air over the heated surface _____________________ and becomes ________________ dense. As the air
becomes less dense, its air pressure ______________________________.
c) _____________ dense air with a higher pressure flows underneath the ________________, less dense air
=warm air rising
3) How do we measure wind speed?
a) Winds are described by their _______________________ and _______________________.
b) _______________________________________ are used to measure wind speed.
4) Wind direction
a) The name of a wind tells you where the wind is coming _________________.
b) For example: A west wind comes from the ______________ and blows toward the ______________.
c) Wind direction is determined with a ________________ ___________________.
d) The wind swings the wind vane so that one end points into the wind.
5) Wind direction represented on a map
a) __________ _________________________ is shown by a line leading into a circle.
b) The example below shows that the wind blew in from the ______________.
6) Wind speed represented on a map
a) The wind speed is shown by the “____________________” on the wind direction line.
b) One “feather” = _________________________.
c) Half of a “feather” = ____________________.
d) A circle within a circle = _____________, ________ ________________.
e) A _________________ = 50 knots.
f) 1 knot = 1.15 mph
g) Feathers are also sometimes called “barbs”
7) Weather symbol example
a) Example #1: What is the wind speed and direction in the image?
b) Wind coming from the __________ at a speed of __________________.
8) Pressure and Wind
a) ______________________ are lines joining places on a weather map that have the same _________
_________________________.
b) Meteorologists use isobars on weather maps to observe atmospheric ___________________ changes
over an area and to make predictions about wind _________________.
c) Remember: Wind is a result of air pressure differences and wind blows from high to low pressure.
d) The closer the isobars are = the ____________________ the wind speed.
e) The further apart the isobars are = the ____________________ the wind speed.
9) Wind Chill Factor
a) Wind blowing over your _________________ removes body heat.
b) The stronger the wind, the more _____________________ is created from the air molecules hitting your
body.
c) This creates heat energy which is absorbed by the water near the surface of your skin, causing it to
________________________.
d) This evaporation removes heat from your body and makes you feel ______________________.
10) Local Winds
a) Local winds are winds that blow over _________________ distances.
b) Local winds are caused by the _________________ ______________________ of Earth’s surface within a small
area.
c) Unequal heating often occurs along the shore of a large body of water.
d) It takes _____________ energy to warm up a body of water than it does to warm up an equal area of
land (water has a high specific heat).
e) During the day the ___________________ warms up faster than the __________________ (unequal heating).
f) At night, the ________________ cools faster than the ______________ (unequal heating).
g)
Land Breeze
i.) Local wind that blows
from the _______________
Sea Breeze
ii.) Local wind that blows
from an ______________
to a body of ____________
or _____________ to the
during the night.
_______________ during the day.
11) Global winds
a) Global winds are winds that blow steadily from specific directions over ____________ distances.
b) Global winds are created by the __________________ heating of Earth’s surface.
c) ____________ air rises at the Equator and ________________ air sinks at the poles.
12) Jet Streams
a) About 10 km above Earth’s surface are bands of high-speed winds called __________ _________________.
b) Meteorologists use the location of some of the jet streams as an aid in ____________________
____________________.
c) Jet streams generally blow __________________ to ____________________.
d) Jet streams form at the boundary of adjacent air masses with significant differences in
_______________________ (polar region vs. Equator).
e) Jet streams have a __________________________ shape.
Part 2: Air Masses and Fronts
13) Air Masses
a) A huge body of air that has a similar _______________________ (warm or cold), ____________________ (dry or
wet), and __________ __________________________ (high or low), at any given height is called an __________
_______________.
b) Four major types of air masses influence the weather in North America:
i) ___________________________ ___________________________
ii) ___________________________ ___________________________
iii) ___________________________ ___________________________
iv) ___________________________ ___________________________
c) Types of air masses:
i) Continental: ________________(_______________)
ii) Mar: ______________ (_______________)
iii) Tropical: ______________/_______________
iv) Polar: _______________
d) The area that the air mass forms over will determine its characteristics.
i) For example: If the source region is an _____________________, the air mass will have a lot of
_______________________.
ii) For example: If the source region is _______________, the air mass will be ____________________.
e) Putting it together
i) Maritime Polar…
_______________ and _________________
ii) _________________________ ____________________…
Dry and cold
iii) Maritime Tropical…
_______________ and _________________
iv) _________________________ ____________________…
Dry and warm
f) Air masses and their origin
Air Masses
Origin
________________________ ________________________
Gulf of Mexico and Atlantic and Pacific Ocean
Continental Tropical
__________________________ and
___________________ ___________________
________________________ ________________________
North Pacific and North Atlantic
Continental Polar
___________________ and ___________________
______________________ and _____________________
g) How air masses move
i) ____________________________ ______________________________-push air masses west to east.
ii) __________ _____________________
14) Fronts
a) The boundary where 2 unlike air masses meet is called a __________________.
b) 4 types of fronts:
i. _____________________
ii. _____________________
iii. _____________________
iv. _____________________
Storms and changeable weather often develop along fronts.
c) Symbols for fronts (see side picture)
d) Front symbols and direction
i) Front symbols point in the _______________________ of _________________________.
ii) Example: In the picture below, the warm, cold, and occluded fronts are moving
_____________________ and the stationary front is not moving in any direction.
iii) Draw a cold front moving east:
iv) Draw a warm front moving south:
v) Draw an occluded front moving northeast:
e) Cold Fronts
i) A cold front is when a fast-moving _____________ air mass takes over a ________________ air mass.
ii) Possible weather: Clouds with possible thunderstorms with heavy rains or snow,
________________ weather on the way.
f) Warm Fronts
i) A warm front is when a ______________ air mass overtakes a slow-moving ______________ air mass.
ii) Possible weather: Humid, light rain or snow for several days; warmer weather on the way.
g) Stationary Fronts
i) A stationary front is when cold and warm air masses ______________, and neither can
______________the other.
ii) Possible weather: The air masses remain ________________ over an area, and may bring
___________days of clouds and precipitation.
h) Occluded Fronts
i) An occluded front is when a _____________ air mass is caught between two __________________ air
masses.
ii) Possible weather: Cloudy and _______________ or __________________.
15) Low Pressure and Weather
a) If you look at a weather map, you will see areas marked with a letter ________ and the L stands
for “_________ _____________________”.
b) Low pressure systems lead to _________________ conditions that often bring _____________________.
c) Here’s how it works:
-Areas of __________ pressure are caused by massive amounts of air ___________________ from
the ground into the atmosphere.
-As the air molecules rise, they take their ______________ with them.
-Air pressure is a ______________.
-Force = ______________ x _________________________.
-Less mass of air molecules left at ground level means _________ air pressure.
-As this air rises it takes whatever water vapor it is holding along with it.
-As altitude increases in the troposphere, the temperature _______________________.
-Eventually the air mass reaches a temperature at or below the _________ _________________ and
the water vapor ________________________.
-___________________ ___________________ rises because colder air cannot hold as much water
vapor.
-This condensation forms clouds.
-If there is enough water vapor in the air, it might also bring ___________________________.
16) High Pressure and Weather
a) If you look at a weather map, you will see areas marked with a letter ________ and the H stands
for “_________ _____________________”.
b) High pressure systems lead to _________________ and __________________ weather.
c) Here’s how it works:
-Areas of __________ pressure are caused by massive amounts of air ___________________ from
the upper troposphere down towards the ground.
-As the air molecules sink, they take their ______________ with them.
-Air pressure is a ______________.
-Force = ______________ x _________________________.
-More mass of air molecules coming to ground level means _________ air pressure.
-As this air sinks it takes whatever water vapor it is holding along with it.
-As altitude decreases in the troposphere, the temperature _______________________.
-The higher the temperature is, the farther from the _________ ______________ you get.
-Warmer air is less dense so it has more space to hold water vapor so ____________________
_________________________ drops.
-This means that condensation does not occur so no clouds form.
-Because there are no clouds, there will be no ___________________________.