Exam 14: Thunderstorms

The majority of lightning strikes occur within the cloud,while only about ____ percent or so occur between cloud and ground.​

____________________ is a discharge of electricity,a giant spark,which usually occurs in mature thunderstorms.​

Because unlike charges attract one another,the negative charge at the bottom of the cloud causes a region of the ground beneath it to become ____________________ charged.​

Describe the atmospheric conditions at the surface and aloft that are necessary for the development of most supercell thunderstorms.(Include in your answer the role that the low-level jet plays in the rotating updraft.)

A small thunderstorm cloud with virga falling out of its base and blowing dust at the ground could warn of a severe hazard to an airplane because​

A thunderstorm is a storm containing ____________________ and ____________________.​

Where the cold downdraft reaches the surface,the air spreads out horizontally in all directions.The surface boundary that separates the advancing cooler air from the surrounding warmer air is called a ____________________.​

To be rated a severe thunderstorm by the National Weather Service,the storm has to have at least one of the following: large hail with a diameter of at least three-quarters of an inch,surface wind gusts of 40 knots or greater,or produces a tornado.​

When thunderstorms are passing over the same area,they are​

Each year,U.S.fire departments respond to more than ____ fires started by lightning in the United States.​

An ordinary thunderstorm​

Large hail is more common in Kansas than in Florida.​

The wind shear associated with several major airline crashes is believed to have been caused by​

Scientists understand with certainty how clouds are electrified.​

When the base of the cloud is positively charged and the ground negatively charged,a(n)____________________ cloud-to-ground lightning flash may result.​

When a thunderstorm is located on the high plains east of the Rocky Mountains,a much larger portion of the storm will typically be located above the freezing level,so hail has a better chance of occurring.

Describe the relationship between flooding and thunderstorms.​

The high winds behind a strong gust front are called ____________________ winds to distinguish them from the rotating winds of a tornado.​

A sound occasionally mistaken for thunder is the ____________________.​

Sometimes there is only one lightning stroke,but more often the leader-and-stroke process is repeated in the same ionized channel at intervals of about four-hundredths of a second.The subsequent leader,called a ____________________ proceeds from the cloud along the same channel as the original stepped leader;however,it proceeds downward more quickly because the electrical resistance of the path is now lower.​