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82 terms

extreme weather

what type of air mass would be responsible for hot, dry summer weather in southern arizona?
temperature, moisture
an air mass is characterized by similar properties of _____ and _____ in the horizontal direction...
cold and dry
one would expect a cP air mass to be....
replaces colder air
at a warm front, the warm air...
generally, precipitation covers a much larger area in front of the cold front
when comparing an average cold front to an average warm front, which of the following is not correct?
a cold front overtakes a warm from
occluded fronts form as:
it is colored red on a weather map
which of the following is not correct concerning a cold front?
cold front
when cold surface air is replacing warm air, the boundary separating the different bodies of air is termed a:
jet streak
the region of strongest winds within a jet stream is called a:
the jet stream flows:
in a wavy pattern from west to east
extra tropical cyclones
middle latitude storms are also known as:
the development or strengthening of a middle latitude cyclone is known as:
ahead of an advancing cold front
on a surface weather map that shows an open wave cyclone, the warm sector is observed
gray, color
on an infrared satellite picture, low warm clouds appear _____ and high clouds appear in _____
the greatest annual number of thunderstorms occur in
the most likely time for an air mass thunderstorm to form is:
late afternoon
air mass thunderstorms begin to dissipate when:
the downdraft spreads throughout the cloud and cuts off the updraft
a group of thunderstorms which develop in a line one next to each other, each in a different stage of development are called:
a multicell thunderstorm
an air-mass thunderstorm is most intense during which stage?
the mature stage
which of the following statements about tornadoes is true?
the us has more tornadoes than any other country in the world
in the us, tornadoes are most frequent during the ___, and least frequent during the ____
spring, winter
the fujita scale pertains to
the strength of a tornado
which region has the most tornadoes in one year?
the great plains
the line between two air masses with the same temperature but significantly different dew points is called?
the dry line
forcasting for 3 to 8 days is known as
medium range
winds around a low pressure system
move counterclockwise towards the center
a strong downward burst of air is
a microburst
what is the weakest category on the fujita scale?
tornadoes typically move
from SW to NE
a mid latitude cyclone typically starts to develop with
an upper level shortwave
what are the 3 conditions needed to form a tornado?
1) convective instability
2) wind sheer
3) trigger (cold front, thunderstorm, lifting mechanism, etc)
explain the stages of cyclogenesis. use terms like: occluded front, warm front, cold front, stationary front, shortwave, divergence.
- beginning: there exists an old frontal boundary where a high pressure hits another high pressure, resulting in a stationary front
-shortwave moves over, causing divergence aloft on the east side of the wave
-warm and cold fronts are formed with divergence aloft
-when cold front meets warm front, occluded front forms, this causes the system to start weakening
explain how a tilted updraft can help to extend the lifetime of a thunderstorm
-the tilted updraft forms rain outside the updraft region
-this rain then falls outside the area, not cutting off the updraft, allowing for longer lifetime
a major snowstorm hits ann arbor. a warm front sits just to the south of the area. which side of the trees do you expect the snow to be on?
-winds to the north of a warm front are from the east, blowing to the center of the low pressure system
is usually takes longer to fly from detroit to los angeles than the other way around. why is this? what is the name of the feature that is causing the difference in travel time?
-jet stream
-the jet stream flows from west to eat, meaning when flying to LA, you will have a headwind, slowing down the plane
from what direction do tornadoes generally move?
-this is due to prevailing westerlies at this latitude and the motion of winds aloft
-tornadoes will also generally follow the counter clockwise of motion of a cold front around a low
in the movie clip shown, identify a scientific principle that is incorrect
-storm rotating the wrong way
-air descending should be warm instead of cool
in order for a surface storm to intensify, the upper-level low (or trough) should be located to the ___ of the surface low
when upper-level divergence of air above a surface low pressure area is weaker than the convergence of surface air, the surface pressure will _____ and the storm itself will ___
increase, dissipate
a mesocyclone refers to
the rotation of a column of air within a thunderstorm
in the us, tornadoes are most frequent during which month?
pressure at the center of the hurricane is ____ than the surroundings at the surface and ____ that the surrounding aloft
lower, higher
the leading edge of a thunderstorm's cold downdraft is known as a:
gust front
lightning may occur
all of the above
-within a cloud
-from a cloud to the ground
-from one cloud to another cloud
a strong but localized downward burst of air is called a:
thunder is caused by
rapidly heating and expanding air
if you see lightning but dont hear thunder, the most likely reason is
the thunder's sound waves are being carried over the top of you
many flash floods are the result of thunderstorms that
move slowly
a tornado cloud that does not reach the earth's surface is called a
funnel cloud
in a violent, multi-vortex tornado, the rapidly rotating small whirls that occur are called
suction vortices
the strongest winds in a hurricane that is moving westward toward Florida would most likely be found on the ____ side of the hurricane
the main source of energy for a hurricane is the:
release of latent heat of condensation
hurricanes do not form
on the equator
which of the following is an atmospheric condition that is not conductive to the formation of hurricanes?
strong upper-level winds
a tropical disturbance called an easterly wave:
all of the above
-moves east to west
-has diverging winds on its western side
-has converging winds on its eastern side
which would you not expect to observe as the eye of a hurricane passes directly overhead?
high winds
in the northnern hemisphere, hurricanes and middle latitude cyclones are similar in that both
have winds blowing counterclockwise about their centers
what direction do hurricanes usually move from beginning to end?
-west or northwest
-due to the easterlies present in the low latituds and the winds aloft
-they will then turn towards the north due to the Bermuda high or to follow the path of warm waters
-hurricanes can then move east if they survive long enough
what atmospheric conditions are necessary for the formation of super cells that spawn tornadoes?
-cold, dry air overlaying warm moist air creates convective instability.
-adding in wind shear will create rotation.
-the combination of cold, dry air, warm,moist air, and warm dry air will create a dry line which creates the ideal conditions for a tornado
-then, some sort of trigger is required to produce the tornado(cold front, thunderstorm, lifting mechanism, etc)
hurricanes are sometimes described as a heat engine. what is the "fuel" that drives the hurricane?
warm moist air will evaporate, rise and release latent heat when it condenses in the cloud.
what 3 things will limit or destroy a hurricane in its infancy
1) wind shear ir high level winds aloft
2) surface cooling below 79 degrees, cutting off the evaporation of warm water
3) loss of water source by moving over land
describe the perfect recipe for tornado formation.
-start with a base of warm moist air and layer that with cold dry air to set up a convective instability
-add in a dollop if wind shear and a small trigger to let your system rise
-then, mix the cP, mT, and cT air masses to form a nice dry line
explain how a clout-to-ground lightning stroke develops
-a stepped leader moves down from cloud in a near random motion to find a ground for the negatively charged cloud.
-once it does, a return stroke moves up from the ground following the path of the stepped leader
-a dart leader now moves from the cloud to the ground following the same path as before
-the dart leader/return stroke process is then repeated several times
describe how a microburst forms
a microburst is a localized downdraft or a small sized downburst. downdrafts form with rapid cooling and falling precipitation
why is the term "wind shear" often used in conjunction with a microburst?
when a microburst strikes the ground, air is forced out in all directions leading to significant amounts of wind shear as the wind is forced in different directions
a typical diameter of a tornado would be
250 meters
all thunderstorms require
hot, humid air
If you see lightning and then hear thunder about 15 seconds later, how far away was the lightning?
3 miles, 5 miles per second
how long does a lightning stoke last?
about 0.1 seconds
a small thunderstorm with virga is falling out of its base and blowing up dust at the ground could warn of a severe hazard to an airplane because:
this could indicate a strong downdraft or microburst
The ring of intense thunderstorms and strong winds located about 20 to 50 km from the center of a hurricane is referred to as the:
eye wall
On the Saffir-Simpson hurricane scale, a hurricane with winds in excess of 155 mi/hr (135 knots) and a central pressure of 910 mb (26.87 in.) would be classified as a category __ hurricane
the downdraft in an air mass thunderstorm is created mainly by
evaporating raindrops that make the air cold and heavy
land and water spouts form from
the cloud down
thunderstorms which produce tornadoes
have rotating updrafts
The first three stages of a developing hurricane are (from first stage to third stage)
-tropical disturbance
-tropical depression
-tropical storm
if there exists a low pressure aloft and a low pressure on the surface what is likely to happen?
the low pressure will become weaker
thunderstorms are likely to occur when atmospheric instability is
-absolutely unstable
-conditionally unstable
hail is more likely to occur in which state?
category ______ of hurricane that are most frequent, while category _____ are more rare
1 or 2, 4 or 5
how is a tornado formed in a super cell thunderstorm
-wind shear is needed to create horizontal roles in wind
-these rolls are advected upwards by the updraft
-the downdraft comes down and squeezes the roll in the vertical plane, causing it to go faster
why is the movie twister unrealistic?
-they live through a tornado without taking any damage
-the shirts always stay white
-flying cows
-trucks are lifted, but people are not