Pressure systems, fronts and weather maps

Grade 9 Science Worksheet

Circle the best answer.

2. 1.

   Model map: isobars 4 mb apart lie 50 km apart west of a low and 200 km apart east of it. Where is the wind stronger, by Bo's reading?

   • Equal on both sides
   • On the east side, where they are farther apart
   • On the west side, where isobars are closer
   • Calm on the west side
3. 2.

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

   Use the picture in question 1.

   • 1,600 mb per 100 km
   • 4 mb per 100 km
   • 0.04 mb per 100 km
   • 16 mb per 100 km
4. 3.

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

5. Read this first

   Use this

   A slow warm front beside a sharp cold front.

6. 4.

   NOAA: as a warm front approaches, what do the clouds and rain do, by Kira's reading?

   • A sudden line of thunderstorms, then clearing
   • Temperatures fall sharply
   • The skies stay clear
   • Clouds lower and thicken, with hours of light to moderate rain
7. 5.

   NOAA: after a cold front passes, what usually happens, by Luz's reading?

   • Nothing changes
   • Clouds lower and thicken for days
   • Winds shift to the northwest, temperatures fall and skies clear
   • Winds turn south, temperatures rise and the air turns humid for days
8. 6.

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

   • Stationary fronts speed up
   • Cold fronts usually move faster and catch up to warm fronts
   • Highs push fronts together
   • Warm fronts move faster and catch cold fronts
9. 7.

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

   • 60 knots
   • 65 knots
   • 75 knots
   • 16 knots
10. 8.

    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 −12 mb per hour, with a high approaching
    • About −2 mb per hour, with fair skies coming
    • About +2 mb per hour, with a high approaching
12. 9.

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

    • Friction with the ground slows it, so it spirals inward
    • It is really blowing out of the low
    • The Coriolis force pulls it into the center
    • The isobars pull it in
13. 10.

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

    Use the picture in question 9.

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