Continental Polar (Cold & Dry) ... A warm front is when the opposite occurs and warm air is replacing colder air. Stationary fronts form when the boundary between the air masses does not move.

Science of Weather: Different Air Masses 02:23. If you hear a meteorologist, say stormy weather is expected, we didn't just pull it out of thin air. Instead, we looked at weather models predicting ...

A cold front marks the boundary between a colder, drier air mass and a warmer and/or more humid air mass. The colder air is often referred to as a continental polar air mass because it originates ...

Continental tropical: hot and dry airmasses that form over the deserts of the western U.S. Maritime polar: most commonly helps form storm systems that move over the pacific northwest.

In fact, it is the Continental Polar/Arctic (cP/cA) from Canada and Maritime Tropical (mT) from the Gulf of Mexico air masses clashing that cause so much severe weather, including tornadoes ...

For the most part, tropical air masses originate between the equator and ~25N while polar air masses originate north of 60N. The area between represents most of the continental US and is also ...

The polar vortex changes periodically, allowing very cold air to move south. (Courtesy of NOAA) When there are extreme events like wind chills 50 below zero and actual temperatures not far off ...

Bone-Chilling Cold Polar Vortex Sweeps Continental U.S. (PHOTOS) Subzero temperatures across the Midwest and parts of the eastern U.S. have commuters, the homeless and anyone else caught outside ...

Editor's Note for Sat. Jan. 18: A polar vortex is set to impact much of the US. Click here for the latest update. A polar vortex is forecasted to blanket most of the continental United States in ...

Polar air masses are not as cold as arctic air, originating over higher latitudes. Tropical air masses have warm and hot temperatures, originating over the lower latitudes.