Pressure systems, fronts and weather maps

Grade 9 Science Worksheet

Circle the best answer.

1. 1.

   A pressure change of 8 mb happens over 200 km (model data). What is that per 100 km, by Esme's math?

   • 0.04 mb per 100 km
   • 16 mb per 100 km
   • 4 mb per 100 km
   • 1,600 mb per 100 km
2. 2.

   Isobars around a center rise toward it: 1016, 1020, then 1024 mb. What kind of center is it, and what weather, by Jun's reading (NOAA)?

   • A front, with snow
   • A high, with rising air and strong storms
   • A low, with rising air and rain
   • A high, with sinking air and fair skies
3. 3.

   A slow warm front beside a sharp cold front. NOAA: as a warm front approaches, what do the clouds and rain do, by Kira's reading?

   • Temperatures fall sharply
   • A sudden line of thunderstorms, then clearing
   • The skies stay clear
   • Clouds lower and thicken, with hours of light to moderate rain
4. 4.

   The four front symbols in a legend. Why do occluded fronts form, by Milo's reading (NOAA)?

   • Highs push fronts together
   • Stationary fronts speed up
   • Cold fronts usually move faster and catch up to warm fronts
   • Warm fronts move faster and catch cold fronts
6. 5.

   A wind line has one pennant, one long barb and one short barb. What speed is it, by Noah's math (NOAA)?

   • 60 knots
   • 75 knots
   • 16 knots
   • 65 knots
7. 6.

   Using 1 hPa = 1 mb = 100 Pa (NOAA), what is a reading of 98,800 Pa in millibars, by Pia's math?

   Use the picture in question 5.

   • 98,800 mb
   • 9,880 mb
   • 988 mb
   • 9.88 mb
8. 7.

   A station's pressure falls from 1012 mb to 1000 mb over 6 hours (model data). What is the change per hour, and what may be coming, by Ren's math?

   • About −2 mb per hour, with a low approaching
   • About −2 mb per hour, with fair skies coming
   • About −12 mb per hour, with a high approaching
   • About +2 mb per hour, with a high approaching
10. 8.

    Without Earth's rotation, wind would blow straight from high to low. What turns it in the Northern Hemisphere, by Tala's reading (NOAA)?

    • The Coriolis force turns it toward the left
    • Friction turns it to the left
    • The isobars bend it back
    • The Coriolis force turns it to the right
11. 9.

    Why does surface wind cross the isobars into a low instead of running along them, by Zee's reading (NOAA)?

    Use the picture in question 8.

    • The Coriolis force pulls it into the center
    • It is really blowing out of the low
    • The isobars pull it in
    • Friction with the ground slows it, so it spirals inward
12. 10.

    Which way does wind circle a Northern Hemisphere high, by Ari's reading (NOAA)?

    Use the picture in question 8.

    • Counterclockwise, spiraling out
    • Clockwise, spiraling in
    • Clockwise, spiraling out
    • Counterclockwise, spiraling in