THUNDERSTORM
INTRODUCTION
Off in the horizon they rumble. Rolling across the
land, they darken the skies to then spark fire in the
darkness. Letting
out
an unmistakable roar.
Thunderstorms are rain showers accompanied by
lightning and thunder. While violent, these weather
phenomena are common with about 2,000 occurring at
any moment worldwide.
A thunderstorm is formed from a combination of
moisture, rapidly rising warm air, and a force capable of
lifting air such as a warm and cold front, a sea breeze, or
a mountain range. All thunderstorms contain lightning.
Thunderstorms may occur singly, in clusters, or in lines.
Thus, it is possible for several thunderstorms to affect one
location in the course of a few hours. Some of the most
severe weather occurs when single thunderstorm affects
one location for an extended time. Thunderstorms can
bring heavy rains (which can cause flash flooding), strong
winds, hail, lightning, and tornadoes. Severe
thunderstorms can cause extensive damage to homes
and property (FEMA, n.d.-f). Lightning is a major threat
during a thunderstorm. Lightnings an electrical discharge
that results from the buildup of positive and negative
charges within a thunderstorm. When the buildup
becomes strong enough, lightning appears as a “bolt.”
This flash of light usually occurs within the clouds or
between the clouds and the ground. A bolt of lightning
reaches a temperature approaching 50,000°F in a split
second. The rapid heating and cooling of air near the
lightning causes thunder.
CAUSES OF THUNDERSTORMS
(https://www.youtube.com/watch?v=pcZn3dGWQ-U)
To form, these storms require three basic
ingredients: moisture, unstable air, and lift. Moisture in
their typically comes from the oceans, and areas near
warm ocean currents evaporate lots of moisture into the
air. Moisture in the air is also responsible for making
clouds. Unstable air forms when warm moist air is near
the ground and cold dry air is up above. To create a
thunderstorm the unstable air, need to have a nudge
upward. This lift usually comes from differences in air
density. Warmer, less dense air rises upward, creating lift.
As the air lifts higher and higher it causes a storm cloud
to grow taller and taller.
All thunderstorms form when warm air in the
lowest layers of the atmosphere rises. In a big
thunderstorm cloud, there are now strong upward winds
and downward winds happening at the same time. These
are called updrafts and downdrafts. This is the most
dangerous stage of the storm when tornadoes, hail,
winds, and flooding can happen. Called an updraft, this
air causes water from the earth's surface to evaporate and
carries the moisture upward to form clouds. The clouds
then build and grow. Sometimes as tall as 10 miles high.
The clouds darken as they fill and become heavy with
water. Cool, dry air from the upper layers of the
atmosphere known as a downdraft then pull this moisture
downward causing it to fall as life-sustaining rain.
TYPES OF THUNDERSTORMS
(https://www.youtube.com/watch?v=zUNEFefftt8)
There are four major types of thunderstorms.
a. Single cell, which are small, weak, and isolated
storms.
 It is also known as a “popcorn” convection.
They tend to grow and die within an hour.
Typically, a person may see these storms on
a hot summer afternoon.
b. Multi-cell, a common of type of storm that
includes cluster of thunderstorms.
 Multi-cell storms can produce new cells and
therefore last as a system for hours. They
also can produce hail, strong winds, brief
tornadoes, and flooding.
c. Squall line, a collection of storms that form a line
hundreds of miles long.
 This group of storms is often accompanied
with high wind and heavy rain. While squall
lines can be intense, they tend to pass
quickly.
d. Supercells, the most intense kind of storm
capable of producing tornadoes.
 They are long-lived. In fact, they occur for at
least one hour. These highly organized
storms feed off an updraft that is tilted and
rotation. This updraft can be up to 10 miles
in diameter and up to 50,000 feet tall.
LIFE CYCLE OF THUNDERSTORM
Thunderstorms have three stages in their life
cycle: The developing stage, the mature stage, and the
dissipating stage.
Stage 1: Developing Stage. The developing stage of a
thunderstorm is marked by a cumulus cloud that is being
pushed upward by a rising column of air (updraft). The
cumulus cloud soon looks like a tower (called towering
cumulus) as the updraft continues to develop. There is
little to no rain during this stage but occasional lightning.
The thunderstorm enters the mature stage when the
updraft continues to feed the storm, but precipitation
begins to fall out of the storm, creating a downdraft (a
column of air pushing downward). When the downdraft
and rain-cooled air spreads out along the ground it forms
a gust front, or a line of gusty winds.
Stage 2: Mature Stage. The mature stage is the most
likely time for hail, heavy rain, frequent lightning, strong
winds, and tornadoes. Eventually, a large amount of
precipitation is produced, and the updraft is overcome by
the downdraft beginning the dissipating stage.
Stage 3: Dissipating Stage. The ground, the gust front
moves out a long distance from the storm and cuts off the
warm moist air that was feeding the thunderstorm.
Rainfall decreases in intensity, but lightning remains a
danger.
 Lightning is the occurrence of a natural electrical
discharge of very short duration and high voltage
between a cloud and the ground or within a cloud.
This violent and sudden electrostatic discharge is
accompanied by a bright flash and typically also
thunder.
WHEN ARE THUNDERSTORMS MOST LIKELY?
Thunderstorms are most likely in the spring and
summer months and during the afternoon and
evening hours, but they can occur year-round and at all
hours.
2. Excessive rainfall can cause flash flooding killing
more people each year than hurricanes, tornadoes,
or lightning.
 Flash Floods: The most dangerous kind of
floods, which occur when excessive water fills
normally dry creeks or riverbeds along with
currently flowing creeks and rivers, causing rapid
rises of water in a short amount of time.
CONVECTION & THUNDERSTORMS
Usually created by surface heating, convection is
upward atmospheric motion that transports whatever is in
the air along with it—especially any moisture available in
the air. A thunderstorm is the result of convection.
BENEFITS OF THUNDERSTORMS
Even though thunderstorms are dangerous, they
can be a great help. They give summer water, cool the
earth, and clean the air. Lightning helps fertilize the soil.
In addition to helping sustain life, thunderstorms
also help maintain the planet's balance of energy and
electricity. When energy specifically in the form of heat
causes water to evaporate, the heat is carried upward with
the water vapor. As the vapor condenses and forms water
droplets it releases the heat into the higher altitudes of the
atmosphere and cools the earth's surface.
3. Hail up to the size of softballs damages cars and
windows, and kills livestock caught out in the open.
 Hail is a form of precipitation that occurs when
updrafts in thunderstorms carry raindrops upward
into extremely cold areas of the atmosphere
where they freeze into balls of ice.
Thunderstorms also help regulate the electrical
balance between the atmosphere and the planet. As
clouds in a thunderstorm develop, excess positive and
negative charges form within them. At a certain point, this
buildup of opposite charges leads to the transfer of
electrons in the form of lightening. This transference of
electricity occurs so quickly that it breaks the sound
barrier. A phenomenon that produces thunder.
DISADVANTAGES OF THUNDERSTORMS
While thunderstorms are necessary for
maintaining balance in the atmosphere, they can also be
hazardous.
1. Lightning strikes create fires.
4. Strong (up to more than 120 mph) straight-line winds
associated with thunderstorms knock down trees,
power lines and mobile homes.
 Downbursts: Common cause of wind damage
from a thunderstorm that can reach over 100
mph. These are caused by air being dragged
down by precipitation. When the air reaches the
ground, it spreads outward across the surface of
the land it encounters in a straight line.
5. Tornadoes (with winds up to about 300 mph) can
destroy all but the best-built man-made structures.
 A tornado is a rapidly rotating column of air
extending down from a thunderstorm to the
surface of the Earth. This mobile, funnel-shaped
cloud typically advances beneath a large storm
system. Tornadoes form when the right
combination of winds meets in a thunderstorm.
HOW TO PREDICT THUNDERSTORMS:
Meteorologists study weather systems to try to
predict the occurrence of thunderstorms and help ensure
the safety of countless communities. Forecasters can use
weather satellites, like those in NOAA's GOES-R series,
to monitor clouds as they grow into thunderstorms. GOES
satellites watch out for lightning too. These satellites are
constantly watching for severe weather, and the
information they gather can help people stay safe during
storms.
RISK OF MORBIDITY AND MORTALITY
In the United States, between 75 and 100
Americans are hit and killed each year by lightning.
Morbidity is reduced if, when caught outdoors, individuals
avoid natural lightning rods such as tall, isolated trees in
an open area, or on top of hill, and metal objects such as
wire fences, golf clubs, and metal tools. It is a myth that
lightning never strikes twice in the same place. In fact,
lightning will strike several times in the same place in the
course of one discharge (FEMA, n.d.-f). Although
thunderstorms and lightning can be found throughout the
United States, they are most likely to occur in the centra
and southern states. The state with the highest number of
thunderstorm days is Florida.
THUNDERSTORM RISK CATEGORIES
There are technically six risk levels ranging from
0 (no severe thunderstorms expected) to 5 (widespread
severe storms expected).
1. Thunderstorms Risk
 This first risk category is represented by light
green and means that there are general or nosevere thunderstorms. There shouldn’t be any
severe thunderstorms, but thunderstorms are
still possible.
2. Marginal Risk
 The second risk category is represented by
dark green and is considered a level one risk.
When this risk level is active for your area it
means isolated, severe thunderstorms are
possible. These storms are most likely limited
in duration, coverage, and intensity, but it’s still
a good idea to be alert.
3. Slight Risk
 A slight risk is the third level of risk,
represented by yellow. While it sounds tame,
it means scattered severe thunderstorms are
possible. They’re only possible because an
organized system is forecast, but the level of
storm severity within the system is varied.
These storms will most likely be short-lived,
not widespread, isolated, and intense. Stay
alert and know where your nearest shelter is.
4. Enhanced Risk
 Enhanced risk is represented by orange and
means that an area of greater severe storm
coverage with varying levels of intensity is
forecast. With this risk category there is
potential for tornadoes, frequent lightning,
damaging winds between 58-70 mph, and hail
with a diameter between 1-2 inches. These
storms can cause fatalities. Please take them
seriously.
5. Moderate Risk
 Moderate risk doesn’t sound so scary, but
these storms can do a lot of damage.
Represented by red, this category’s storms
have a high likelihood for tornadoes, frequent
lightning, damaging winds in excess of 70
mph, and large hail in excess of 2 inches in
diameter. This category is active only when
government forecasters believe widespread
severe storms that are intense and long-lived
are likely.
6. High Risk
 High risk forecasts are quite rare. Typically,
forecasters issue high risk areas when they
expect particularly strong and widespread
severe storms or tornado outbreaks. There is a
strong likelihood of strong and/or long-lasting
tornadoes. These storms also contain frequent
lightning, damaging and long-lasting winds in
excess of 80 mph, and hail in excess of 2
inches. There is also a strong likelihood of
structural damage.
MANAGEMENT OF THE DISASTER
BEFORE:
1. Learn about your local community’s emergency
warning system for severe thunderstorms
2. Discuss thunderstorm safety and lightning safety
with all members of your household
3. Pick a safe place in your home for household
members to gather during a thunderstorm This
should be away from windows, skylights and
glass doors that could be broken by strong winds
or hail
4. Make a list of items to bring inside in the event of
a severe thunderstorm
5. Make trees and shrubbery more wind resistant by
keeping them trimmed and removing damaged
branches
6. Protect your animals by ensuring that any outside
buildings that house them are protected in the
same way as your home
7. Consult your local fire department if you are
considering installing lightning rods
DURING:
1. Listen to local news or NOAA Weather Radio for
emergency updates. Watch for signs of a storm,
like darkening skies, lightning flashes or
increasing wind.
2. Postpone outdoor activities if thunderstorms are
likely to occur. Many people struck by lightning
are not in the area where rain is occurring.
3. If a severe thunderstorm warning is issued, take
shelter in a substantial building or in a vehicle with
the windows closed. Get out of mobile homes that
can blow over in high winds.
4. If you can hear thunder, you are close enough to
be in danger from lightning. If thunder roars, go
indoors! The National Weather Service
recommends staying inside for at least 30
minutes after the last thunderclap.
5. Avoid electrical equipment and telephones. Use
battery-powered TVs and radios instead.
6. Shutter windows and close outside doors
securely. Keep away from windows.
7. Do not take a bath, shower or use plumbing.
8. If you are driving, try to safely exit the roadway
and park. Stay in the vehicle and turn on the
emergency flashers until the heavy rain ends.
Avoid touching metal or other surfaces that
conduct electricity in and outside the vehicle.
9. If you are outside and cannot reach a safe
building, avoid high ground; water; tall, isolated
trees; and metal objects such as fences or
bleachers. Picnic shelters, dugouts and sheds
are NOT safe.
AFTER:
1. Never drive through a flooded roadway. You
cannot predict how deep the water may be.
2. Stay away from storm-damaged areas to keep
from putting yourself at risk from the effects of
severe thunderstorms.
3. Continue to listen to a NOAA Weather Radio or to
local radio and television stations for updated
information or instructions, as access to roads or
some parts of the community may be blocked.
4. Stay away from downed power lines and report
them immediately.
5. Watch your animals closely. Keep them under
your direct control.
REFERENCES
Thunderstorms: Everything you need to know. Earth
Networks. (2019, July 23). Retrieved January 26,
2022,
from
https://www.earthnetworks.com/thunderstorms101/
Thunderstorm safety. American Red Cross. (n.d.).
Retrieved
January
26,
2022,
from
https://www.redcross.org/get-help/how-to-preparefor-emergencies/types-ofemergencies/thunderstorm.html
Thunderstorm basics. NOAA National Severe Storms
Laboratory. (n.d.). Retrieved January 26, 2022,
from
https://www.nssl.noaa.gov/education/svrwx101/th
understorms/
National Geographic. (2019, April 12). Thunderstorms
101 | national geographic. YouTube. Retrieved
January 26, 2022, from
https://www.youtube.com/watch?v=zUNEFefftt8
SciJinksVideo. (2019, April 1). What causes a
thunderstorm? YouTube. Retrieved January 26,
2022,
from
https://www.youtube.com/watch?v=pcZn3dGWQU
VIDEOS TO WATCH:
 https://www.youtube.com/watch?v=c48IdUzouo0
 https://www.youtube.com/watch?v=zUNEFefftt8
 https://www.youtube.com/watch?v=pcZn3dGWQ
-U