Lightning may be defined as a sudden electrostatic discharge that happens during an electrical storm between the clouds, or on the ground. It is related to the weather through the formation of thunderstorms. In a thunderstorm cloud, the rising air causes various types of precipitations, which are then frozen. These include small ice crystals and large pellets of ice and snow. The smaller crystals hold positive charges and are propelled upwards while the denser pellets, which are negatively charged, remain suspended or fall towards the ground (Leonard). During this action, a collision between the pellets and ice crystals occurs thus forming a thunderstorm with a charging mechanism. Essentially, the aftermath of this is a positively charged top of the cloud and a negatively charged middle. Additionally, during this period, the ground below these clouds results in an opposite charge of the overhead charges. Then, the charge difference between the ground and the cloud become too large developing a conductive air channel between the ground and cloud. Lastly, the step leader (small amount of charge) moves towards the ground and connects with opposite charges of an upward leader and a powerful discharge is instantly experienced between the ground and the clouds thus, the forming lightning (Leonard).
A thunderstorm is defined as a series of abrupt electrical discharges that result from various atmospheric conditions, which result in sudden light flashes and trembling waves known as thunder and lightning (Leonard). They form when warm air forms under much cooler air causing instability in the atmosphere. Then, warm air rises and cools causing condensation which turns vapor into droplets hence the formation of rainv and this is known as the developing stage. When warm air continues rising, the droplets crystalize and form hail since theybecome too heavy to be supported by updrafts of air (Leonard).This is known as the mature stage. Moreover, while moving through the cloud, hail collects a negative charge by rubbing against smaller ice crystals that are positively charged. At the cloud base, a negative charge forms at the point of accumulation of hail while a positive charge is created from the lighter crystals near the top of the cloud. At this point, the downward flowing air dominates hence a decrease in rain intensity. This is called the dissipating stage (Leonard). An attraction forms between the negative charge and the surface of the earth along with other clouds and objects. If the attraction becomes too strong, the charges either discharge or come together to create a balance in the flash of lightning difference thus, creating a lightning bolt. When air is rapidly expanded and heated by lightning, it produces a loud clap known as thunder. The process may lead to severe thunderstorms.
A tornado is a column of air rotating violently, which extends from a cumuliform cloud to the ground. Until debris and dusts are picked up, tornadoes might appear nearly transparent (Leonard). sdditionally, they can move in any direction but the average one moves from southwest to northeast though they can change direction of motion at any time. The forward speed of a tornado stands at an average of 30mph but some vary from a nearly stationary average of 70 mph. They occur at any time of the day with the strongest ones having winds that rotate up to more than 200mph(Leonard). Additionally they tend to accompany hurricanes and tropical storms as they advance towards land. Other than land tornadoes, some form on water resulting to water sprouts which can move onshore causing damage to coastal areas.
The formation of tornadoes is dependent on the direction and speed of wind. Before the formation of thunderstorms, winds change their direction while increasing speed with altitude. then, this forms an invisible, horizontal rotating effect based on the lower atmosphere. Additionally, air rises within the thunderstorm updraft and tilts the rotation of air such that it changes from horizontal to vertical, which creates an area of rotation that extends between 2-6 miles, hence a strong rotation within which a tornado forms (Leonard). Essentially, three types of tornadoes exist and they include weak, strong, and violent tornadoes. They are measured by tools such as barometers, Dopplerradars, turtles, and, EF scales which,their measure different factors such as pressure, temperature, humidity, and strength.
There are five basic steps of observing and monitoring tornadoes on the ground in the National Weather Service (Leonard). These steps work towards warning the greatest number of people of impending tornadoes in time. They include;
- The tornado watch-meteorologists use the latest computers, satellite data, and radar to monitor different weather elements.
- Spotters-these are people who have been trained on techniques of spotting tornadoes and reporting to the weather service.
- Civil defense and state police. The state police relay any message from the National Weather Service.
- The media- they help in reaching a large majority of people with cooperation from the national weather service.
- The users- these include all people within the vicinity of a tornado warning area who are required to help in reaching the greatest number of people to issue warnings.
Leonard, Barry. Thunderstorms…Tornadoes…Lightning: Nature’s Most Violent Storms: A preparedness Guide. DIANE Publishing, 2009