How forecasts are made and why they are uncertain

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   A forecast card reading 40% beside a 60% chance of none. NWS: what does a 40% chance of rain mean, by Ari's reading?

   • A 40% chance that the spot gets at least 0.01 inch of rain
   • It will rain 40% of the day
   • Rain will cover 40% of the area
   • It will not rain
3. 2.

   With a 30% chance of rain, what is the chance of no measurable rain, by Bo's math?

   • 130%
   • 70%
   • 30%
   • 3%
4. 3.

   Town A has a 20% chance of rain and town B a 60% chance. How many times greater is B's chance, by Kira's math?

   Use the picture in question 2.

   • 1.2 times
   • 40 times
   • 3 times
   • 80 times

5. Read this first

   Forecast accuracy (NOAA)

   Forecast length	About how often right
   5 days	90%
   7 days	80%
   10 days or more	about 50%

6. 4.

   About how often is a 10-day or longer forecast right, by Luz's reading (NOAA)?

   • About 90% of the time
   • About 80% of the time
   • Each time, with no misses
   • About half the time
7. 5.

   Why do forecasts get less certain further ahead, by Milo's reading (NOAA)?

   • Small errors in the estimates grow as the atmosphere keeps changing
   • Models run faster further out
   • The Sun changes after a week
   • Forecasters stop working after 5 days, so later days are just guessed at
9. 6.

   What do computer weather models use to calculate the future, by Noah's reading (NOAA)?

   • The average of last year's weather
   • Random numbers
   • Math equations that describe how the atmosphere moves
   • Old almanac guesses
10. 7.

    Which sources give weather models their starting data, by Ren's reading (NOAA)?

    Use the picture in question 6.

    • Climate normals, by themselves
    • Weather balloons, satellites, surface stations and aircraft
    • Newspapers and almanacs
    • Old forecasts, by themselves, copied forward again and again
12. 8.

    What is the main difference between weather and climate, by Tala's reading (NOAA)?

    • Weather is rain, and climate is temperature
    • Time: weather is now, and climate is the average over years
    • Place: weather is local, and climate is in space
    • They are the same thing
13. 9.

    Over how many years are climate normals averaged, by Zee's reading (NOAA)?

    Use the picture in question 8.

    • 30 years
    • 5 days
    • 1 year
    • 300 years
14. 10.

    Which statement is a weather forecast rather than a climate statement, by Esme's reading?

    Use the picture in question 8.

    • Winters here are usually dry
    • Rain is likely tomorrow afternoon
    • This city's 30-year normal rainfall is 900 mm
    • Summers here average 30 °C