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K12 LibreTexts

11.18: Weather Maps

  • Page ID
    5525
  • What can a weather map tell you about the weather?

    A lot! A weather map indicates all sorts of things to let you know the forecast. It also may have some cute graphics associated with it.

    Weather Maps

    You may have seen weather maps like the one pictured below (Figure below). A weather map shows weather conditions for a certain area. The map may show the actual weather on a given day. It may show the predicted weather for some time in the future. Some weather maps show many weather conditions. Others show a single condition.

    Weather map showing high and low air pressure contours

    This weather map shows air pressure contours. Which state has the lowest air pressure shown on the map?

    Air Pressure Maps

    The weather map pictured above (Figure above) shows air pressure. The lines on the map connect places that have the same air pressure. Air pressure is measured in a unit called the millibar. Isobars are the lines that connect the points with the same air pressure. The map also shows low- and high-pressure centers and fronts. Find the cold front on the map. This cold front is likely to move toward the northeast over the next couple of days. How could you use this information to predict what the weather will be on the East Coast?

    Other Weather Maps

    Instead of air pressure, weather maps may show other weather conditions. For example, a temperature map might show the high and low temperatures of major cities. The map may have isotherms, lines that connect places with the same temperature.

    Summary

    • Weather maps graphically depict weather conditions.
    • Isobars are lines of constant pressure.
    • Isobars indicate pressure cells.

    Review

    1. What are the gray lines on the weather map pictured above?
    2. How are high- and low-pressure centers indicated on a weather map?
    3. What do the blue and red hatched lines indicate on the map?

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