Ms. Cawsey
Geog 12
WEATHER MAPS
Note a couple of points:
1st: The wind is “FROM” the direction, so in this one, it is FROM the northwest
2nd: Don’t memorize clouds, just memorize heights and in the multiple-choice options
see the correct height
3rd: Dew point is when the air gets cold enough to loose some of the moisture (not
always in dew form)
4th: REMEMBER a COLD front coming in means there will be a + sign and a WARM
front coming in means there will be a – sign (in the 3 hour air pressure change line.
5th: The icicles on map point into warm air and the rain drops on the map face into cold
air.
6th: Occlusion is when a cold front takes over a warm front so warm air goes aloft
Make your OWN station! (data made up!)
Temperature: 2
Wind Direction: SW 63-74
Cloud: ½ Tufted Cirrus
Present Weather: Steady, Light
Drizzle
Dew point: -1
Air Pressure: 219
Pressure Change: -3
Temperature: 27
Wind Direction: W 2-5
Cloud: ¼ Swelling Cumulus
Present Weather: Smoke
Dew point:23
Air Pressure: 269
Pressure Change: -6
Temperature: -3
Wind Direction: N 12-19
Cloud: Overcast Cirro-Stratus
Present Weather: Steady snow
Dew point: -3
Air Pressure: 231
Pressure Change: +26
Temperature: 5
Wind Direction: SE 30-39
Cloud: 7/8  Cumulo Nimbus
Present Weather: Fog in sight
Dew point: 4
Air Pressure: 158
Pressure Change: +6
Temperature: 16
Wind Direction: NW 11-19
Cloud: Little  thin alto stratus
Present Weather: nothing
Dew point: -3
Air Pressure: 118
Pressure Change: -7
Weather Map Questions:
Using the map on page 188, fill in the following chart and answer the following questions
City
Los Angeles,
CA
Prince
George
Toronto, Ont
Tampa, FL
Air Pressure
Air Pressure
change in 3
hrs
Temperature
Dew Point
Cloud Type
Cloud Cover
Wind
Direction &
speed
Present
state of
weather
1. Why is there so much rain in Nashville? ___________________________________
2. Is there going to be any precipitation in Boisie, Idaho on this day? Why/ why not?
__________________________________________________________________
3. Above Regina there is a big H. What does it stand for? ____________________
Now, around that H is a circle called an isobar. What do isobars tell us?
________________________________. What is it for the circle around the H?
______________. What air mass is impacting that area (look slightly to the right of
the H near Hudson Bay) ________________________________________
4. When you have a front line that has icicles on one side and rain drops on the other, it
means it is moving _______________________________
5. What kind of front does Denver have coming towards it? ________________ What
is happening to its air pressure therefore? ____________________
6. Winnipeg just had what kind of front go over it? _________________ We know
this because what is happening to its air pressure? ___________________________
Air Pressure
 We live at the bottom of an ocean of air. Constant changes in weight or pressure of this
air on a given surface often gives significant warnings of future weather.
Air pressure is measured in
Millibars (mb) internationally.
This allows people to
exchange weather information around the world. In Canada the metric measurement is
Kilopascals (kPa).
To place an air pressure number on a weather chart, take the last
Ex 1012.3mb
996.7mb
3 digits.
12.3
96.7
 On a weather chart the decimal is
Reported air pressure
omitted in the air pressure.
1012.3mb
996.7
If your plotted pressure is
101.23kPa
99.67kPa
123
967
greater than 700 add a 9 to the left of the number.
Ex chart Pressure: 967 then becomes 9967
If your plotted pressure is
less than 500 add a 10 to the left of the number.
Ex chart Pressure: 123 then becomes 10123
You then change these numbers into mb or kPa units.
For mb move the decimal
Ex 9967
10123
For kPa move the decimal
Ex 9967
10123
1 place from the right
996.7mb
1012.3mb
2 places from the right
99.67kPa
101.23kPa
Change the following air pressure numbers to kPa. Remember to add a 10 or 9 to the
number. Show all the steps.
1.) 123______________________________________________________
2.) 993______________________________________________________
3.) 209______________________________________________________
4.) 988______________________________________________________
Now, go back to page 188  See how the isobar over Los Angeles is 1008 but the air
pressure is 073.
The exam WILL have a question where you have to convert the mb to kPa or visa-versa
Change the air pressure number to mb. Remember to add a 10 or 9 to the number. Show
all the steps.
1.) 967
2.) 207
3.) 833
4.) 163
Change the following to numbers that can be placed on a weather chart. Fill in the
measurement unit.
1.) 109.45_______
2.) 98.86________
3.) 977.6_______
4.) 102.35________
Air Pressure
 We live at the bottom of an ocean of air. Constant changes in weight or pressure of this
air on a given surface often gives significant warnings of future weather.
Air pressure is measured in
____________
(mb) internationally. This allows people
to exchange weather information around the world. In Canada the metric measurement is
_______________
(kPa).
To place an air pressure number on a weather chart, take the last
Ex 1012.3mb
996.7mb
12.3
96.7
 On a weather chart the decimal is
Reported air pressure
__________ in the air pressure.
1012.3mb
101.23kPa
Pressure plotted on chart 123
If your plotted pressure is
number.
____ digits.
996.7
99.67kPa
967
___________ than 700 add a 9 to the left of the
Ex chart Pressure: 967 then becomes 9967
If your plotted pressure is
_______ than 500 add a 10 to the left of the number.
Ex chart Pressure: 123 then becomes 10123
You then change these numbers into mb or kPa units.
For mb move the decimal
Ex 9967
10123
For kPa move the decimal
Ex 9967
10123
___ place from the right
996.7mb
1012.3mb
____ places from the right
99.67kPa
101.23kPa
Change the following air pressure numbers to kPa. Remember to add a 10 or 9 to the
number. Show all the steps.
1.) 123
2.) 993
3.) 209
4.) 988
Change the air pressure number to mb. Remember to add a 10 or 9 to the number. Show
all the steps.
1.) 967
2.) 207
3.) 833
4.) 163
Change the following to numbers that can be placed on a weather chart. Fill in the
measurement unit.
1.) 109.45_______
2.) 98.86________
3.) 977.6_______
4.) 102.35________