ATOC 1050: FINAL EXAM
69 Cards in this Set
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For west winds across the Rocky Mountains Boulder would be located on the ____________ side of
the mountains and you would expect ___________ skies in Boulder.
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leeward, mostly sunny
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You would expect air to _______ on the windward side of a mountain range resulting in ________
skies.
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rise, cloudy
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For west winds across the Rocky Mountains you would expect lee waves to form on the _________
side of the Rocky Mountains.
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east
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A hydraulic jump in the atmospheric flow over a mountain range marks the transition from ______
winds upstream of the jump to _______ winds downstream of the jump and is often characterized by
__________ vertical winds.
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strong, weak, strong
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Strong downslope winds can be regarded as a shooting flow. This shooting flow develops because a
large volume of air must pass between a mountaintop and ______.
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an inversion
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As air descends dry adiabatically from 3,000 m near the crest of the Rocky Mountains to 1,500 m near
Boulder, CO you would expect the air to warm approximately _____ degrees C.
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15
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. For a Chinook to occur in Boulder there needs to be high pressure to the _________ of the Rocky
Mountains and low pressure to the __________ of the Rocky Mountains with an inversion upstream of
the mountains located 1 to 2 km ___________ mountaintop.
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west,
east,
above
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A lee trough is an area of ________ pressure on the ________ side of the mountains.
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low, downwind
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Santa Ana winds are typically __________ than Chinook winds in Colorado.
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weaker and warmer
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In North America you would expect Chinook winds to occur __________
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east of the Rocky Mountains
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True or false: A thunderstorm that produces a wind gust of 80 knots would be classified as a severe
thunderstorm by the National Weather Service.
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TRUE
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Which of the following is required in order for a severe thunderstorm to form, but is not required for a
non-severe thunderstorm to form?
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Vertical wind sheer
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What are the three stages of an airmass thunderstorm (from first to last stage)?
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cumulus, mature, dissipation
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Airmass thunderstorms typically form________________
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in the interior of an airmass away from the edge of the airmass
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The mature stage of an airmass thunderstorm is characterized by ___________________.
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precipitation beginning to fall from the thunderstorm
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A downdraft forms in a thunderstorm due to ______________.
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-the drag from falling precipitation
-the presence of warm, moist air
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Thunderstorms are also known by what cloud name?
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cumulonimbus cloud
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What types of thunderstorm has an anvil?
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All thunderstorm have an anvil
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Where is the most common location for a frontal squall line to form?
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Ahead of a cold front
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A supercell is _________________
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a rotating thunderstorm
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A frontal squall line often forms the ___________ of a mid-latitude cyclone comma cloud as viewed
from a satellite.
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tail
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An overshooting top occurs when an updraft is _________ and penetrates _________________.
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strong, the tropopause
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A gust front in a thunderstorm forms when the ____________ spreads out ________
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drowndraft, at the ground
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How long does a typical frontal squall line last?
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Hours to days
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. A conditionally unstable environment can develop when air near the ground is ___________ and
__________ air moves in aloft.
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heated, cold
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. In an environment where supercell thunderstorms are likely to form the air at lower levels in the
atmosphere is likely to have come from ____________ and the air at upper levels is likely to have come
from ____________.
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the Gulf of Mexico, the Rocky Mountains
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What sequence of precipitation would you expect to occur as a supercell thunderstorm approaches you
from the southwest?
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light rian, moderate rain, heavy rain, hail
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A mesocyclone is __________________________.
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-the rotating circulation in a supercell that is associated with the updraft
-associated with an area of lower pressure
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True or false: Tornadoes only occur in the United States.
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FALSE
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Rotation in a supercell occurs when ________________.
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the rotation created by the shear associated with the low-level jet is tilted into the vertical direction by
the updraft
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Vortex stretching _____________ the rotation in a supercell.
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strengthens
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. Tornado formation by vortex breakdown requires __________________.
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a downdraft to form in the center of the mesocyclone
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Landspout tornadoes form in ______________ thunderstorms as a result of ______________.
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non-supercell, stretching of small vortices that form due to shear across a front
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On the enhanced Fujita scale of tornado intensity the weakest tornadoes are rated _____ and the
strongest tornadoes are rated _____.
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EF0, EF5
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On a Doppler radar radial velocity image a small area where radial winds rapidly switch from
outbound to inbound is a __________.
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mesocyclone signature
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The Storm Prediction Center would issue a ____________ when conditions are favorable for the
development of thunderstorms that contain strong winds, hail, frequent lightning, heavy rain, and possible
tornadoes.
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severe thunderstorm watch
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. This type of vortex forms along the boundary of cool outflow ahead of a thunderstorm.
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Gustando
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A cluster of thunderstorms in the tropics with a wind speed of 50 knots would be classified as a
_______________.
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tropical storm
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The term hurricane is used in the __________ Ocean, while the term typhoon is used in the
___________ Ocean to refer to the strongest tropical weather systems.
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Atlantic, western Pacific
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A hurricane with a central pressure of 900 mb would be rated as a category _____ hurricane on the
Saffir-Simpson scale.
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5
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Over the past century the annual property damage due to tropical cyclones in the United States has
generally _____________.
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increased
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The nearly cloud free area at the center of a hurricane is the ______________.
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Eye
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You would expect air to be _________ in the eyewall of a hurricane and to be __________ in the eye.
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rising, sinking
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The sea level pressure ____________ as you move from the edge to the center of a hurricane.
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decreases
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The largest storm surge with a hurricane occurs on the __________ side of the hurricane when it
makes landfall.
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right
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Low level convergence in the tropics will cause air to __________ and results in _____________.
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rise, the formation of thunderstorms
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What four factors are required for a cluster of thunderstorms to become a tropical cyclone?
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SST > 27 deg C, deep layer of warm ocean water, weak vertical wind shear, a location at least 5
degrees of latitude poleward of the equator
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As a cluster of thunderstorms becomes organized into a hurricane the pressure at the center
__________ and the wind speed ___________.
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decreases, increases
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The two primary causes of a storm surge are_____________________
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Onshore winds and low pressure swell
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TRUE/FALSE Flooding typically causes more damage than winds in tropical cyclones.
a) true
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TRUE
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What is the importance of boundaries in thunderstorm development?
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Lifting occurs among boundaries
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Why is wind sheer important to sever thunderstorms?
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Vertical wind shear separates the updraft and downdraft, preventing precipitation from falling into the updraft; it can also induce rotation in a thunderstorm
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Why are MCSs important to the central plains?
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They provide summer rainfall which is important for agriculture
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How large are MCSs and how long do they last?
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200 to 300 miles in diameter, lasting on the order of 6-12 hours.
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Along what type of fronts do frontal squall lines typically form?
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surface cold fronts, dry lines or along upper level fronts
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During what time of year are frontal squall lines most common?
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a cool season (fall and spring)
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How large are frontal squall lines and how long can they last?
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100s of kilometers long, several hours
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What is a supercell thunderstorm? What characteristic distinguishes supercells from
other types of severe thunderstorms?
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Supercells are large rotating thunderstorms in which the updraft and downdraft
circulations maintain the storm’s structure for a long time period.
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What type of severe weather do supercells produce?
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large hail, strong straight-line winds and tornadoe
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What are boundary intersections and what role do they have in supercells?
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Boundary intersections are the locations where two boundaries meet. Supercells
have a tendency to develop at these points of intersection.
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Do global climate models simulate thunderstorms? Why or why not?
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No. The size and time scale of thunderstorms are too small to be resolved by a
climate model – the required resolution is too computationally intensive.
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How is the transition from winter to summer likely to change the frequency of
thunderstorms in a global warming scenario.
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The thunderstorm season should start earlier and end later, suggesting that more
thunderstorms would be likely. However, it is unclear that the ingredients for
thunderstorms (moisture, lift, and instability) will be available so that additional
thunderstorm activity will actually occur…
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Will global warming increase the frequency of thunderstorms?
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it is difficult to state definitively
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Describe typical tornado characteristics such as width, range of wind speeds, and time
on the ground
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Width: 50 to 800 meters (150 ft to 0.5 mile); range of wind speeds: 57 kts to
over 174 kts (65 mph to over 200 mph); time on ground: minutes to over an
hour
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What is a mesocyclone? What is a typical width of a mesocyclone?
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Mesocyclone is a cyclonic circulation, typically several kilometers or less in
diameter, within the updraft region of a supercell thunderstorm, normally
coinciding with the region where tornadoes form.
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How does a “tornado family” develop?
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Each forms in a new updraft within the supercell, typically
on the southwest side of the storm.
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Each forms in a new updraft within the supercell, typically
on the southwest side of the storm.
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Horizontal wind shear creates a series of small vortices. When these vortices
develop under an updraft they are stretched into tighter circulations until a
landspout forms.
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What is the EF-scale? How is an EF-scale rating assigned to a tornado?
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EF-scale is Enhanced Fujita scale. The extent of damage from a tornado is
assessed using Damage Indicators and prescribed tables that allow for the
estimation of wind speed ranges based on damage.
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. What is the “tornado vortex signature” in a radial velocity field obtained from Doppler
radar?
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A tight couplet in radial velocity, often at the pixel to pixel level.
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ATOC 1050: EXAM 1