Air masses

What is an air mass? How do air masses originate?

  • Air mass = immense body of air with uniform properties (temperature and moisture content)

  • Originate when: Air maintains some position for days/weeks over a large, uniform surface where winds are light

    • Source region/where forms affects main properties

      • Temp depends on if air is from tropics or poles

      • Humidity depends on if air is from land or see

Maritime Tropical (mT)

  • Warm and humid

  • Source region = over water near equator

Maritime Polar (mP)

  • Cool/cold and humid

  • Source region = over water near high lat./poles

Continental Tropical (cT)

  • Warm and dry

  • Source region = over land near equator

Continental Polar (cP)

  • Cold and dry

  • Source region = over land near mid to high lat./poles

Continental Arctic (cA)

  • Very cold and dry

  • Source region = over land near high lat./poles

    • **Don’t really need to know much about it

How do air masses affect weather?

  • May take days to pass

    • Weather of the place air mass move to becomes like the weather of the source region

    • Fast-moving air masses bring more extreme weather than slow-moving ones

Which air masses are most important to us in NY?

  • The weather in NY is most influenced by two air masses:

    • cP from Central Canada

    • mT from Gulf of Mexico