Pressure systems, fronts and weather maps

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   A student says widely spaced isobars mean strong wind. Which reply fits NOAA, by Jun's reading?

   • No; the spacing shows rain amounts
   • Correct; wide spacing means a steep gradient and very fast wind
   • No; close spacing means a steep gradient and stronger wind
   • Correct; the spacing shows temperature
2. 2.

   The four front symbols in a legend. A student says the red line with half-moons is a cold front. Which reply fits NOAA, by Kira's reading?

   • No; it is an occluded front
   • Correct; the colors on weather maps are random and carry no meaning
   • Correct; red half-moons mark cold air
   • No; that is a warm front, and a cold front is blue with triangles
3. 3.

   NOAA: 1013.25 mb equals 29.92 inches of mercury. About how many mb is 1 inch of mercury, by Luz's math?

   • About 0.03 mb
   • About 1,043 mb
   • About 33.9 mb
   • About 983 mb
4. 4.

   Model map: isobars 4 mb apart lie 80 km apart near one low and 320 km apart near another. How many times steeper is the first gradient, by Milo's math?

   • 4 times
   • 16 times
   • 240 times
   • 0.25 times

5. Read this first

   Use this

   A slow warm front beside a sharp cold front.

6. 5.

   A station reports falling pressure, clouds lowering and thickening, steady light rain and an east wind (model data). Which front is coming, by Pia's reading (NOAA)?

   • An occluded front that has stalled
   • A warm front
   • A cold front that just passed
   • A high-pressure center
7. 6.

   A station reports a line of thunderstorms, then a wind shift to the northwest, a 15 °C drop and clearing skies (model data). What passed, by Ren's reading?

   • The center of a high
   • A stationary front
   • A warm front
   • A cold front
8. 7.

   The four front symbols in a legend. A purple line with triangles and half-moons on one side sits near an old low. What does it show, by Tala's reading (NOAA)?

   • A stationary front
   • An occluded front, often a sign the system is mature and weakening
   • A dry line
   • A new cold front forming
9. 8.

   Which summary of pressure systems fits NOAA, by Zee's reading?

   • Wind blows from low pressure toward high pressure
   • Highs: sinking air, fair skies, clockwise; lows: rising air, clouds, counterclockwise
   • Highs and lows both spin clockwise in the north
   • Highs: rising air and storms; lows: fair skies
10. 9.

    The four front symbols in a legend. Which summary of front symbols fits NOAA, by Ari's reading?

    • Cold: red half-moons; warm: blue triangles
    • Occluded: blue triangles; cold: purple
    • Cold: blue triangles; warm: red half-moons; stationary: alternating; occluded: purple
    • Each front is drawn as a plain black line
11. 10.

    Which summary of reading wind on a weather map fits NOAA, by Bo's reading?

    • Close isobars mean calm; a pennant means 5 knots
    • Wide isobars mean strong wind; each barb counts 1 knot of wind speed
    • Close isobars mean strong wind; barbs count 10, 5 and 50 knots
    • Winds circle highs counterclockwise in the north