Thunderstorm Forecasting
Natural Disasters
Home		 Thunderstorm
Home		 Thunderstorm
Forecasting
Disaster
Agencies

Weather Glossary
Weather Forecasting Instruments
 
Thunderstorm Formation
All thunderstorms form from cumulonimbus clouds. Heavy rain showers, dangerous lightning, thunder, and sometimes hail, tornadoes or strong winds can occur during thunderstorms. A multicell thunderstorm is made up of more than one thunderstorm cell. The winds in this kind of thunderstorm has winds blowing upward in a single updraft and winds blowing down toward the earth in downdrafts. Multicell thunderstorms aremade up of two to four thunderstorm cells, but some of the cells might not be active. In a multicell thunderstorm there is at least one active cell.
NOAA Photograph In thunderstorms air is always moving. An updraft is a small current of wind that blows in an up and down motion. The updraft could turn into a cumulus cloud if there is enough moisture. A downdraft wind happens when cool or cold air in the cloud suddenly falls towards the earth.
           
NOAA Photograph   NOAA Photograph
Thunderstorm Updraft in Cloud   Thunderstorm Downdraft in Cloud
Severe Thunderstorms
The most severe thunderstorms are pushed ahead of cold air masses. There are several things that a thunderstorm must have in it before it becomes a severe thunderstorm. Hail that is larger than 3/4 of an inch wide, winds that blow faster than 58 miles per hour, and tornadoes are the three things that make a thunderstorm severe. Severe thunderstorms are pushed by jetstream winds that are in the troposphere.
Thunderstorm Climatology
Thunderstorms can occur just about any time of the year and any where. Severe thunderstorms usually will occur in the spring and fall because there are more cold and warm air fronts than at any other time of the year. Frontal thunderstorms happen when cold air is more dense than warm air. When a cold front reaches a warm air mass, it quickly makes the warm air rise, making the conditions for severe weather in the troposphere.This situation in the trosphere can cause winds of up to 58 miles per hour, large hail, and even tornadoes. A frontal thunderstorm looks like a thick line of thick cumulonimbus clouds.
 
NASA Image NASA Photograph
Activities in the Different Layers of the Earth's Atmosphere Layers of the Earth's Atmosphere
Thunderstorm Watches and Warnings
What are thunderstorm watches? They are conditions of severe thunderstorms in and close to the watch area. which means if there is a thunderstorm in that area it is expected in 34 hours or less. What is a thunderstorm warning? It is a a severe thunderstorm that has actually been observed by spotters or indicated on radar, and is occurring in the warning area. Which also means that it is expected in 24 hours or less.
Thunder and Lightning

What is lightning? Is it just a flash of some sort, or is it something else? Well first of all lighting is really dngerous. It is also five times hotter than the sun. Lightning is an electrical discharge made to balance the differences between and negative charges and positive between two clouds, within a cloud ,or between the cloud and the ground. What causes lighting to strike? A negative charge at the bottom of the cloud is attracted to a positive charge at the earth's ground.When more positive than negative charges

 
Thinkquest Meet the Team Site Outline Interactives Links
Photographic Citations:
Photographic citations can be found by passing the mouse over the photograph.

Text Citations:

The Weather Channel:
 http://www.weather.com/encyclopedia/thunder/form.html