Exam 14: Thunderstorms

Ordinary thunderstorms only last about one hour and begin to dissipate when​

One theory of cloud electrification states that during the formation of precipitation,regions of separate charge exist within tiny cloud droplets and larger precipitation particles.In the lower part of these particles we find negative charge,while in the upper part we find positive charge.​

How does negative cloud-to-ground lightning differ from positive cloud-to-ground lightning?​

In the valleys of central and southern California,dry,sinking air produces an inversion that inhibits the development of towering cumulus clouds during the summer.Hence,in these regions,thunderstorms are most frequent in winter and spring,particularly when cold,moist,conditionally unstable air aloft moves over moist,mild surface air.​

Positive lightning has the potential to cause more damage because it generates a much higher current level and its flash lasts for a longer duration than negative lightning.​

Left-moving supercell thunderstorms are uncommon in the Northern Hemisphere,yet are very common in the Southern Hemisphere.​

Squall lines generally do not form​

If thunderstorms bring repeated heavy rain to a region for days or weeks,the result can be one or more ____________________ floods.​

A cloud-to-ground lightning discharge will sometimes appear to flicker.This is because​

During the summer,what conditions prevail near the surface over the Great Plains that help a hailstone survive as ice all the way to the ground?​

List and describe the stages of development of an ordinary thunderstorm.About how long does a single ordinary thunderstorm cell last?​

The highest frequency of thunderstorms in the United States occurs in​

When warmer hailstones come in contact with colder ice crystal,an important phenomenon occurs: There is a net transfer of ____________________ ions (charged molecules)from the warmer object to the colder object.​

Sinking air warms,yet the downdrafts in a thunderstorm are usually cold.

The most likely time for an ordinary thunderstorm to form is​

Clouds,which appear to slowly spin about a horizontal axis,are called ____ clouds.​

An ordinary thunderstorm is most intense during the ____ stage.

Even though the bright return stroke of lightning travels from the ground up to the cloud,it happens so quickly that our eyes cannot resolve the motion,and we see what appears to be a continuous bright flash of light.​

Positive lightning is the most common with ____ thunderstorms.​

Cloud-to-ground lightning begins within the cloud when the localized electric potential gradient exceeds ____ volts per meter along a path perhaps 50 m long.