Exam 11: Air Masses and Fronts

The weather forecast "Increasing cloudiness and warm today, with the possibility of showers by evening. Turning much colder tonight. Winds southwesterly, becoming gusty and shifting to northwesterly by tonight" suggests that a(n)___________________ front is going to pass the area.

When warm and cold air masses collide, the warm air is forced upward. Why does this occur?

Drylines may be detected by Doppler radar when insects and insect-eating birds congregate along them. On the radar screen, the echo from insects and birds shows up as a thin line, called a fine line.

Maritime polar air masses along the East Coast of the United States are usually ____________________ than those along the nation's West Coast.

What type of air mass would be responsible for hot, muggy summer weather in the eastern half of the United States?

A true cold front on a weather map is always ____.

A(n)____________________ is an extremely large body of air whose properties of temperature and humidity are fairly similar in any horizontal direction at any given altitude.

During the spring, on a warm, sunny day in Boston, Massachusetts, the wind shifts from southwesterly to northeasterly and the weather turns cold, damp, and overcast. This suggests that a "back-door" cold front approached Boston from the ____.

"Back-door" cold fronts are most common in the Pacific Northwest of the United States.

____________________ are not warm fronts or cold fronts, but represent a narrow boundary where there is a steep horizontal change in moisture.

The only indication on the station model of past weather conditions is the ____.

The "average" speed of a cold front is about half that of an "average" warm front.

An mT air mass lying above a cold ground surface represents a(n)____________________ situation.

Along the boundary between continental polar and maritime tropical air masses, widespread precipitation and storminess are often found.

A(n)___________________ front has essentially no movement.

Maritime tropical (mT)air masses are responsible for daily afternoon thunderstorms along the Gulf Coast.

Freezing rain more commonly occurs with warm fronts than with cold fronts.

What type of weather would you expect to see form when a cP air mass moves across warm water? Would conditions be any different when mP air moves across a cold land surface?

Wintertime mP air masses are less common along the Atlantic coast of North America than along the Pacific coast mainly because the ____.

On a weather map, the transition zone between two air masses with sharply contrasting properties is marked by ____.