Thunderstorms have been defined as storms produced by a cumulonimbus cloud and continually followed with the aid of lightning and thunder. They are normally of brief duration, seldom over 2 hrs. They also are followed by way of strong wind gusts, heavy rain and, sometimes, hail.
How thunderstorm is produced?
Thunderstorms originate from cumulonimbus clouds. The simplest difference between an regular bathe cloud and those storms is that they’re continually related to thunder and lightning. According to Trewartha, a thunderstorm is like a thermodynamic device wherein the potential electricity of the latent warmth of condensation is rapidly converted into the kinetic electricity of ascending air currents. Presence of heat and humid air inside the decrease layers of the ecosystem is an vital pre-requisite for the development of a thunderstorm. Atmospheric instability and extreme convective activity are other vital requirements for their starting place and growth.
Intense convective interest in warm and moist air makes possible the lightning discharge within the atmosphere. So, the thunderstorms have been called with the aid of many meteorologists as the violent showers produced by atmospheric instability. Thus, a thunderstorm represents the weather phenomenon which combines strong wind gusts, thunder, lightning, torrential rains and cumulonimbus clouds etc. All in one. That is why thunderstorms are considered as a climate factory.
The vertical extent of a thunderstorm relies upon on the intensity of ascending air currents. The peak of thunderstorms levels from four to 20 km. The growing air cools at the dry adiabatic lapse fee upto the bottom of the thunder cloud. In the convective cells of the thunderstorm, the dry air is from time to time carried to the middle of the clouds whereby the cooling technique keeps rapidly. Besides, there is a marked seasonal and latitudinal variation within the heights of thunderstorms. The most peak is attained for the duration of the warm season in the tropical regions.
If there’s an upper- air inversion, it acts as a barrier to stop convective activity and thus the further boom of a thunderstorm is checked. The pinnacle of the cumulonimbus cloud is anvil-shaped and the forward-bulging crest points towards the direction of the hurricane movement. There is heavy precipitation from the well-advanced thunderstorms. At times, while the vertically ascending air currents or updrafts are vigorous, hail can also fall from the front part of a thunder cloud. Lightning and thunder always accompany torrential rains.
Since excessive heating of the earth’s floor units up convection! Currents in the atmosphere, it follows that thunderstorms usually develop in summer season in the tropical and the center latitude regions. That is why these storms have a choice for the latter a part of the day when maximum temperatures are recorded. Besides, adequate supply of moisture is likewise needed, so that the latent warmth of condensation may also be to be had to sustain the storm.
Stages of development of Thunderstorm:
- Cumulus stage:
In the cumulus stage there is an updraft in the course of the cell. The cloud contains precipitation particles. As the cloud grows larger in size, the updrafts become more potent and more widespread. These updrafts from time to time acquire speeds of 160 km according to hour so that they may be able to uphold the large hailstones aloft. In the higher components of the cloud, massive quantities of liquid water particles and ice crystals co-exist, a truth which initiates the downdraft.
- Mature stage:
The level of maturity is marked through strong updrafts and downdrafts inside the cloud. Heavy precipitation falls on the ground. The frictional drag exerted by precipitation, in keeping with Byers, adjustments the updraft into a downdraft which continues in addition on its own.
The falling of precipitation and the start of downdrafts take location simultaneously. It is to be mentioned that at adulthood the top parts of the cloud are characterized via updrafts and the decrease components, on the opposite hand, have greater pronounced downdrafts. The severity of thunderstorm is at its peak. Maximum of lightning and thunder are seen on this level. Weather at the surface is characterized by means of heavy rainfall and high-speed winds. The maximum excessive turbulence, frequently a climate danger to flying aeroplanes, marks the weather aloft.
- Dissipating stage:
The disappearance of updrafts marks the start of the dissipating degree. This stage is characterized by susceptible downdrafts and mild rain. Downdraft air spreads on the ground outward. The outflowing floor winds are frequently very gusty and wind pace being nearly high. Sometimes the downdraft which spreads over the entire vicinity of the cell produces most welcome cooling impact on hot summer time days.
Factors Supporting Thunderstorm Development:
- Atmospheric instability:
Atmospheric instability is the most essential component in thunderstorm development. Surface heating brings approximately an detail of instability inside the heat and moist air lying near the surface. That is why heat and wet air turns into volatile in spring and summer when it’s far heated from below. Air mass thunderstorms develop on this way.
- Lifting of potentially unbalanced air:
Frontal and orographic thunderstoms end result from the overall uplift of potentially volatile air. In the uplifted air mass big quantity of latent warmness is launched to keep the thunderstorm. In the frontal lifting potentially, volatile air is pressured to upward push over a wedge of colder and denser air. That is why rapidly advancing bloodless the front produces a large variety of thunderstorms. At times, a slim band of thunderstorms develops much in advance of a cold front. Such thunderstorms are known as squall lines.
- Huge supply of warm and moist’ air:
Most favorable conditions for the development of thunderstorms is furnished by the nice and cozy and wet air in the lower layers of the atmosphere. Besides, a very steep lapse charge upto extensive heights inside the atmosphere helps of their formation. Conditional and convective instability accentuate the convective activity inside the atmosphere. The depth of the storm also relies upon on the significance of the atmospheric instability.
- Thickness of clouds:
Thickness of clouds, in keeping with Trewartha, is an additional factor within the improvement of thunderstorms. Thickness of a cloud from the condensation degree upto the freezing level ought to be approximately three hundred meters. In the middle- range zones no thunderstorm would develop until the ascending air currents reach the freezing level.
How is Thunder Produced?
The sound emitted by rapidly increasing gases along the channel of a lightning discharge is known as thunder. A lightning stroke produces first-rate heat alongside its path. The air is heated to 10000oC which results in rapid enlargement of the air column. The great expansion of air sends vibrating stress wave outward which actions at the speed of sound (3000 meters per second). The noise produced by the sort of wave is referred to as thunder.
