Mid-Latitude Storms

Mid-Latitude storms are weather systems that:
- Bring rain to Canadian regions.
- Extend from 25º to 50º latitude.
- Form the area where cold A air masses meet moist, warm m air masses.
- When two masses collide, storms are born.

Air Masses
Air masses are bodies of air that develop over large areas of the earth’s surface
Two conditions are necessary for formation:
Source region – air must stay over an region for long period of time
The air must be stable
Air masses take on characteristics of the region
Warm maritime air masses – formed over water
Cold continental air masses – formed over land

The five types of North American air masses are:
Continental Tropical (cT)
Maritime Tropical (mT)
Maritime Polar (mP)
Continental Polar (cP)
Arctic (A)