Group 7's presentation was about thunderstorms. It defined thunderstorms, explained how they form through 3 stages (cumulus, mature, dissipating), and described the main types (orographic, air mass, frontal). It covered key characteristics like lightning, thunder, heavy rainfall, strong winds. Both positive impacts like natural rainfall and nitrogen fixation, and negative ones like lightning hazards, hail damage, tornadoes, and rainfall floods were discussed. The presentation ended with thunderstorm safety tips.

1. Group Members from group 7:
Antor-157 Shoity-147 Shuvo-151
Rakib-145 Rafiul-149
Welcome to our presentation

2. Thunderstorms

3. What is Thunderstorm?
• A thunderstorm is a weather condition
characterized by heavy rain and wind
accompanied by lighting, thunder, sometimes
with hail and tornados.
• According to A.N. Strahler , “A thunderstorm is
an intense local storm associated with large,
dense cumulonimbus clouds in which there are
very strong updraft of air.”

4. How do thunderstorms
form?
♠Condition for forming a Thunderstorm :
For a thunderstorm to form, three conditions must
exist.

5. Condition : 1
• There must be an abundant source
of moisture in the lower levels of
the atmosphere.
• As the moisture condenses, it
releases latent heat.
• The release of latent heat keeps the
cloud warmer then the air around it,
which is crucial in maintaining the
upward motion of the cloud.

6. Condition : 2
• Some mechanism ( orographic, lifting,
temperature difference, fronts) must lift the air so
that the moisture can condense and release heat.
Condition : 3
• The portion of the atmosphere through which the
cloud grows must be unstable.

7. 3 Stages of thunderstorm formation
1. Cumulus Stage:
The sun heats the earth’s surface
during the day. The heat on the
surface warms the air around it.
Since warm air is lighter than cold air,
it starts to rise (known as an updraft).
If air is moist, then the warm
condenses into a cumulus cloud. The
cloud will continue to grow as long
warm air below it continues to rise.

8. 3 Stages of thunderstorm formation
2. Mature Stage:
When the cumulus cloud becomes
very large, the water in it becomes
large and heavy. Raindrops start to
fall through the cloud when the rising
air can no longer hold them up.
Meanwhile, cool dry air start to enter
the cloud. Because cool air is heavier
them warm air, it start to descend in
the cloud(known as a downdraft) and
it pulls the water downward to make
rain.

9. 3 Stages of thunderstorm formation
3. Dissipating Stage:
After about 30 min, the thunderstorm
begins to dissipate. This occurs when
the downdrafts in the cloud begins to
dominate over the updraft. Since
warm moist air can no longer rise,
cloud droplets can no longer form.
The storm dies out with light rain as
the cloud disappears from bottom to
top.

10. Types of thunderstorms
Thunderstorms are classified according to where
they occurred are mainly three types.
Thunderstorms Orographic
Air mass
orographic

11. Orographic Thunderstorms
They are formed when the air is pushed
up a mountain side. The warm, moist air
rises from surface up to the slope of
mountain .The cloud gets too heavy and it
precipitates itself out on the windward side
of mountain and then it will collapse and
dissipate without ever crossing the
mountain.
This type of thunderstorms is found on the
windward side of a mountain range. In the
united states we would found this type of
thunderstorms on western slopes of rokey
mountains and also the western slopes of
Applachians.
This type thunderstorm create heavy
rainfall on the wind ward side of mountain.
Orographic Thunderstorms

12. Air mass Thunderstorm
Air mass thunderstorm is a
special kind of storms that occurs
when the air is humid, warm and
unstable .
They are the single cell or isolated
storms that are caused by the
heating of the ground from solar
radiation . This is why they to be
happening during the hottest part
of the day.
They are mostly vertical on
structure and short lived storm.
They are mostly found in tropical
environmental regions like Florida.

13. Frontal Thunderstorms
Frontal thunderstorms are
associated with the collision of two
air masses, which are referred to us a
frontal.
It form when a cold air mass forces
warm, moist, air mass above it. This
violent motion can be developped
into significant vertical movement,
resulting thunderstorms.
They are often found in Mid-Latitude,
Continental Regions, Coastal Regions
etc.
r
FrontalThunderstorms

14. The Main Characteristic of
Thunderstorm
Lightning
Thunder
Heavyrainfall
Strong
winds

15. Lightning
• Lightning is a powerful electrical
discharge that occurs during a
thunderstorm.
• It results from the separation of
positive and negative charges
within a cloud or between the
cloud and the ground.
• Lightning bolts can be seen as
bright flashes of light and are
often accompanied by a crackling
or rumbling sound.

16. Lightning Facts
• The majority of lightning occurs within clouds…only about 20%
between cloud and ground.
• The lightning strokes heats a narrow channel to roughly 54,000
F—much hotter than the surface of the sun. Causes air to expand
explosively—producing thunder.
• Light from lightning moves at the speed of light (186,000 miles per
second), while sound of thunder only moves at 1/5 mile per
second.
• Can use the difference to determine how far the lightning stroke is
for every 5 second difference-one mile away

17. Thunder
Thunder is the sound produced by the rapid
expansion of air due to the intense heat
generated by lightning.It is often described
as a loud rumble or boom and can be heard
shortly after seeing the lightning flash.The
time delay between seeing the lightning and
hearing the thunder can help estimate the
distance of the storm.

18. Strong Winds
Thunderstorms are often
accompanied by strong gusts of wind,
which can cause branches to break,
trees to be uprooted, and debris to be
thrown around.These strong winds
can also contribute to the rapid spread
of wildfires, especially during dry
conditions.
The gusts in Ordinary thunderstorms can range from 48 to 80
kilometers per hour.
Wind gusts in Supercells can exceed 160 kilometers
per hour.

19. Heavy Rainfall
Thunderstorms are known for their
intense and heavy rainfall, which can
lead to flash floods and
waterlogging.The rapid accumulation of
water on the ground can result in
hazardous conditions and damage to
property and infrastructure.

20. Thunderstorms and the Environment
Thunderstorms play a vital role in the Earth's
atmosphere.They help transport heat,
moisture, and pollutants between the surface
and the upper atmosphere.Thunderstorms can
contribute to nitrogen fixation, which
enriches the soil with nutrients.

21. Positive effect of Thunderstorm
• Natural Rainfall
• Nitrogen Fixation
• lighting recharge earth’s negative charge

22. Natural Rainfall
Thunderstorms bring much-needed rainfall to
replenish
1.Water sources.
2.Nourish crops.
3.Support ecosystems.

23. Nitrogen Fixation
Nightning fixes nitrogen in the ground/soil through
electro-magnetic chemical processes.Each bolt of
lightning carries electrical energy that is powerful
enough to break the strong bonds of the nitrogen
molecule in the atmosphere.Free nitrogen atoms in
the air bond with oxygen in the air to create nitrogen
oxides, which dissolve in moisture to form nitrates
that are carried to Earth's surface by
precipitation.Lightning accounts for some naturally
occurring reactive nitrogen-worldwide each year,
lightning fixes an estimated 3-10 teragrams (Tg), the
usual measurement unit for discussing the
global nitrogen cycle.

24. lighting recharge Earth’s negative charge
During a thunderstorm, lightning imparts
negative electric charges
(-) to the earth's surface, thereby
replenishing earth's negative charges

25. Negative effect of Thunderstorm
• Lightning Hazards
• Hail Damage
• Tornadoes
• Rainfall and Flood

26. Lightning Hazards
• When lightning strikes the ground or a
structure, it can cause injuries or fatalities
to people and animals in its vicinity.
• It can also start wildfires if it strikes dry
vegetation or flammable materials.
• Additionally, lightning can damage
electrical systems and electronic devices,
leading to power outages and equipment
failures.

27. Hail Damage
• Hail is solid precipitation in the form of balls or
lumps of ice that are created within powerful
thunderstorms with strong updrafts.
• Hailstones vary in size, from small pellets to
large golf ball sized or even larger stones.
• During severe thunderstorms, large hailstones can
cause significant damage to crops, vehicles,
roofs, windows, and other property.
• Hail damage can result in expensive repairs and
insurance claims.

28. Tornadoes
• Tornadoes can uproot trees, destroy
buildings, and throw debris at high
speeds, posing severe risks to people
in their path.
• Tornadoes are associated with
supercell thunderstorms, which are
large and long-lived storms with
intense rotation.

29. Thunderstorm Safety Tips
• Stay Informed
• Seek Shelter Indoors
• Avoid Electrical Appliances
• Avoid Windows and Doors

30. Pay attention to weather forecasts and
warnings issued by local authorities.Have a
weather app or a battery-powered NOAA
Weather Radio to receive updates
during power outages.
Stay Informed

31. Seek Shelter Indoors
If a thunderstorm is approaching, seek
shelter in a sturdy building.Avoid small,
open structures and isolated trees.

32. Avoid Electrical Appliances
Refrain from using electrical appliances,
including corded phones and computers,
during a thunderstorm.
Lightning can cause power surges that may
damage electronics.