Download Unit 5 : Storms A. Wind Patterns 1. Coriolis effect – wind (moving air

Unit 5 : Storms
A. Wind Patterns
1. Coriolis effect – wind (moving air) is deflected to the right in the northern
hemisphere and to the left in the southern hemisphere
2. trade winds
a. air sinks, warms, and moves toward the equator in a westerly direction
b. at the equator, the air rises again and moves back to 30o where is sinks
and starts the process all over again
c. occurs at 30o north and south latitude
3. prevailing westerlies
a. surface winds move towards the poles in an easterly direction
b. occurs between 30o and 60o north and south latitude
4. polar easterlies
a. flow from the northeast to the southwest in the northern hemisphere
b. wind flow is reversed in the southern hemisphere
c. characterized by cold air
d. occurs between 60o latitude and the poles
5. jet streams – narrow bands of fast,
high-altitude westerly winds
a. can flow up to 185 km/h at
elevations of 10.7 to 12.2 km
B. Predicting Storms
1. Doppler Effect – is the change in wave frequency that occurs in sound or light
as the energy moves towards or away from the observer
2. meteorologists use Doppler radar to
plot the speed at which raindrops
move toward or away from a radar
station
3. because moving rain drops is caused by
wind, it provides a good estimation of
wind speed associated with precipitation
C. Hurricanes (Tropical cyclones)
1. large, rotating, low pressure storm
2. aka tropical cyclone
3. thrive on the tremendous
amount of energy in warm,
tropical oceans
4. as water evaporates from the
ocean surface, heat is stored
which is later released when the
air begins to rise and water vapor
condenses into clouds and rain
5. the rising air creates an area of low
pressure at the ocean surface
6. as more warm air moves toward the low pressure center to replace the air that
has risen, the Coriolis effect causes the moving air to turn counterclockwise
in the northern hemisphere which produces the cyclonic rotation
(Before and After pictures from hurricane Ike in 2008 over Texas)
Hurricane Precautions:
o Prepare enough water and food for several days.
o Fill tank of car with gas and take out cash.
o Seek shelter in a secure structure that will withstand strong winds.
o Move to an area away from storm surge.
o Stay away from windows and doors during the storm and do not go outside.
o Close all interior doors and go to an interior first floor room such as a bathroom or
a closet
o Lie on the floor under a table
D. Thunderstorms
1. a storm with thundering
and lightning and typically with
heavy rain
2. lightning is electricity caused
by the rapid rush of air in a
cumulonimbus cloud which separates
electrons and causes an electrical imbalance
3. caused by:
a. abundant moisture in the atmosphere
b. rising of air so that the moisture can
condense which releases heat
c. air must continue to cool for the
growing cloud to stay warmer than the
surrounding air which causes
instability in the atmosphere
4. supercell – self-sustaining, extremely powerful
storm
Thunderstorm Precautions
o The best defense against thunderstorms is to stay inside a sturdy building or
shelter that can protect you from deadly lightning, large hail, damaging winds,
flooding rain and tornadoes.
o Once in a shelter, stay away from windows and avoid electrical equipment and
plumbing. Remember to bring pets inside. If there is time, secure loose objects
outside as these objects often become dangerous flying debris in high winds.
o Avoid open spaces, isolated objects, high ground and metallic objects.
o Get out of boats and away from bodies of water. Remember, if you can hear
thunder, you are close enough to the storm to be struck by lightning.
E. Tornados
1. a violent, whirling column of air in contact with the ground
2. typically associated with supercells
3. forms when wind speed and direction change suddenly with height
Tornado Precautions
o Prepare for tornadoes by gathering emergency supplies including food, water,
medications, batteries, flashlights, important documents, road maps, and a full
tank of gasoline.
o When a tornado approaches, take shelter indoors—preferably in a basement or an
interior first-floor room or hallway.
o Avoid windows and seek additional protection by getting underneath large, solid
pieces of furniture.
o Avoid automobiles and mobile homes, which provide almost no protection from
tornadoes.
o Those caught outside should lie flat in a depression or on other low ground and
wait for the storm to pass