A document tackling about the basis of Thunderstorms: -What is Thunderstorm? -How do the Thunderstorms form? -What is the difference between thunder and lightning? Between a water spout and a tornado? -What are the types of Lightning? of a Thunderstorm? -What are some signs of an approaching thunderstorm? -What are some precautionary measures to do before and during a thunderstorm? -Case of Thunderstorms in the Philippines and on Planes

1. THUNDERSTORMS

2. WHAT IS A THUNDERSTORM?
A thunderstorm is weather condition characterized by
heavy rain and wind accompanied by lightning, thunder;
sometimes with hail and tornadoes. It can last for 30 minutes to
several hours.

3. HOW DO
THUNDERSTORMS
FORM?

4. CONVECTION IS THE KEY!
Warm air near the ground rises and cooler air sinks. Warm
surface air will continue to rise since it is less dense than the
surrounding air. The rising air is called updraft, while the
downward moving air is called downdraft. Thunderstorms form
when there is a balance of updrafts and downdrafts.
As air continues to rise, it cools and condenses to form
clouds. As condensation progresses, the clouds increase in size
and spread upward into an anvil-like shape, forming
cumulonimbus clouds.

5. 3 STAGES OF THUNDERSTORM
FORMATION*

6. 1 - CUMULUS STAGE
The sun heats the Earth's surface during
the day. The heat on the surface and warms the
air around it. Since warm air is lighter than cool
air, it starts to rise (known as an updraft). If the
air is moist, then the warm air condenses into a
cumulus cloud. The cloud will continue to grow
as long as warm air below it continues to rise.

7. 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 starts to enter
the cloud. Because cool air is heavier than warm air, it
starts to descend in the cloud (known as a downdraft).
The downdraft pulls the heavy water downward,
making rain.

8. 3 - DISSIPATING STAGE
After about 30 minutes, 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. DID YOU KNOW?
Lightning is around 27 000 degrees Celsius
That is six time hotter than the surface of the sun!
Lightning is an electric current. To make this electric
current, first you need a cloud.
Now, the cloud becomes a thundercloud. Lots of
small bits of ice bump into each other as they move
around. All these collisions cause a build up of
electrical charge.

11. Eventually, the whole cloud fills up with
electrical charges. Lighter, positively charged
particles form at the top of the cloud. Heavier,
negatively charged particles sink to the bottom of
the cloud.
When the positive and negative charges grow
large enough, a giant spark - lightning - occurs
between the two charges within the cloud. This is
like a static electricity sparks you see, but much
bigger.

12. When sufficiently ionized, air can
become electrically conductive (plasma). Air
is ionized when the separation between
protons and electrons is greater than before,
meaning more movement for these charged
particles. This ability to move is what makes
conduction possible.
While ionization occurs and plasma is
being formed above, the objects on the
ground reach out to the clouds by growing
finger-like electrical discharges called
streamers. Even our bodies can produce
streamers which is why it is not advised to be
outdoors during a thunderstorm.

13. SHOCKING!
Most lightning happens inside a cloud, but sometimes
it happens between the cloud and the ground.
A build up of positive charge builds up on the ground
beneath the cloud, attracted to the negative charge in the
bottom of the cloud. The ground's positive charge
concentrates around anything that sticks up - trees,
lightning conductors, even people! The positive charge from
the ground connects with the negative charge from the
clouds and a spark of lightning strikes.

15. THUNDER VS LIGHTNING
Plasma travels downward to create a path
for the current to flow. The electrons surge
down to meet the streamers, creating
lightning.
As lightning strikes, the air around it is
heated and expands rapidly to the point
that it explodes.
Thunder is a shockwave caused by this
explosion, which manifests as a loud
booming sound.

16. TYPES/
CLASSIFICATIONS
OF LIGHTNING*

18. DO YOU KNOW?
Lightning strikes can occur in succession, and can
certainly hit the same place repeatedly. Such is the
case with the 444-meter tall Empire State Building,
which gets struck 25 to 100 times a year.
• Light travels faster than sound so we see lightning
before we hear thunder.
• The closer you are, the shorter the gap between the
lightning and thunder.
Astraphobia is the fear of thunder and lightning.

19. TYPES OF THUNDERSTORMS
Thunderstorms can be classified by severity
or structure.
According to the National Weather Service
of U.S., a thunderstorm is severe if it
contains wind gusts of at least 94 km/h,
hail at least an inch in diameter, or a
tornado.
A thunderstorm can be single cell, multi-
cell, or supercell, or a squall line.

20. SINGLE CELL vs MULTI CELL THUNDERSTORM
A single cell thunderstorm is a short-
lived storm consists of a single updraft-
downdraft couplet. It is capable of
producing heavy rainfall and lightning.
A multi-cell thunderstorm is a system
of individual cells. Each cell usually
lasts for 30 minutes to an hour, while
the entire system can last for hours.
Multi-cells may produce hail, flood, and
brief tornadoes.

21. SUPERCELL THUNDERSTORM
A supercell thunderstorm is a
highly organized thunderstorm
with a large rotating updraft
that can be 20 km in diameter
and 15 km in height. It can last
for several hours and produces
violent tornadoes.

22. SQUALL LINE
A squall line is a group of storms
arranged in a straight line. It is shorter-
lived than multi-cells and supercells,
and are less likely to produce
tornadoes. Squall lines are typically 15
to 20 km long, but can reach up to
hundreds of kilometers.

23. THUNDERSTORMS IN THE PHILIPPINES
Most of the thunderstorms that have occurred in the Philippines
are associated with typhoons

24. In 2013, a thunderstorm
caused by tropical depression
Wilma created a water spout,
or a tornado that originated
from a water body. This
tornado hit north Bohol and
Cebu, with winds up to 80
km/h.
One week later, a tornado
with winds of 200 km/h also
hit Leyte. Tornadoes are not
uncommon in the Philippines,
but are not as frequent or
severe as in countries such as
the U.S.

25. WATER SPOUT
VS
TORNADO*

26. A waterspout is an intense
columnar vortex (usually
appearing as a funnel-shaped
cloud) that occurs over a body
of water.
A tornado is a rapidly rotating
column of air that is in contact
with both the surface of the
Earth and a cumulonimbus
cloud or, in rare cases, the base
of a cumulus cloud.

27. In 2016, two individuals
were killed in a house fire
ignited by lightning during
a thunderstorm brought by
typhoon Marce.
This typhoon caused heavy
rains and thunderstorms in
Davao. It was suspected
that lightning struck the
main electricity line,
igniting the house.

28. SIGNS OF AN APPROACHING
THUNDERSTORM
An approaching thunderstorm has apparent warning signs, such as gentle
warm air suddenly replaced by strong, chilly bursts of wind, lightning strikes
accompanied by deafening thunder, and abrupt, intense rain. Apart from these
observable indicators, there are forecasts and weather bulletins to let you know of
any impending thunderstorms.

29. PAG-ASA WEATHER FORECASTS
PAGASA begins a thunderstorm watch
when thunderstorm formation is likely
within the next twelve hours. Updates will
be disseminated thru media networks and
the PAGASA website
When there is indication that a
thunderstorm is threatening a specific area
within the next two hours, PAGASA issues
a thunderstorm advisory.

31. Precautionary Measures
Before and During a
Thunderstorm

32. When a thunderstorm is imminent, you can do the following:
Stay indoors and make sure windows, doors, or other openings
are locked;
Seek shelter. A car is ideal for this purpose because it lets the
current bounce around its walls, not because the rubber tires keep the
charges away;
Unplug electrical appliances and avoid using corded phones or
any gadget physically connected to the wires outside. It is safe to use
cellular phones and remote controls;

33. When a thunderstorm is imminent, you can do the following:
Avoid any contact with water. This includes bathing and
washing your hands;
If on water, get to land immediately; and
If in an open field, keep distance from trees/high points
because they have a higher possibility of being struck by lightning.

34. THE LIGHTNING CROUCH*Squat down with your feet together,
your head tucked to your chest or
between your knees, and your hands
covering your ears or flat against your
knees. Do not lie flat on the ground, as
this gives the lightning a larger target.
This is a difficult position to hold, and
it definitely doesn't guarantee your
safety. However, by making it easier
for a lightning strike to flow over your
body rather than through vital organs,
you may be able to sustain a smaller
injury from it.
Cover your ears and close your eyes
to protect against nearby thunder and
bright lightning flashes.

35. CASE STUDY:
FLYING IN STORMS

36. It is incredibly dangerous to fly into a hurricane so
airlines cancel their flights when there is a hurricane, but
flights usually go on through regular thunderstorms.
Thunderstorms bring a lot of hazards to aircrafts.
Dangers of windshear, microbursts, severe turbulence,
icing and torrential rain can all take place at the same
time when the airplane comes across a thunderstorm.
Airplanes that wander into a thunderstorm are at risk of
structural failure or even the physical breaking of planes.

37. Windshear is a sudden change in
wind direction and velocity and this
results to severe turbulence.
Microbursts are severe updrafts,
downdrafts, and horizontal
windshear that can really test the
performance capabilities of the pilot
and the plane.

38. Modern airplanes are
equipped to withstand
lightning strikes but pilots
still try to avoid lightning
because occasionally, there
can still be damages
incurred from lightning
strikes. Lightning strikes
cannot always be avoided
because even if the plane is
far from the thunderstorm,
the lightning can still reach
the plane.

39. Pilots regularly encounter areas
with thunderstorms and they
need to rely on the plane’s
onboard weather radar and
windshear detection systems,
ground-based observation, and
experience, to make the safest
decisions possible. Sometimes it
can be hard to make decisions
because there are other factors
to consider such as the route
and the schedule that they have
to follow