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term
|
definition
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term
|
Definition
An air mass reflects the characteristics of its
source region |
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term
|
definition
Cold Canadian air mass
– Moist, tropical air mass |
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term
| – Moist, tropical air mass |
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definition
the temperature and moisture characteristics of
their source regions: |
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term
Air masses are generally classified according to
the temperature and moisture characteristics of
their source regions: |
|
definition
– Moisture designated as maritime (m) (wetter) or
continental (c) (dryer)
– Temperature designated by latitude as arctic (A), polar
(P), tropical (T), equatorial (E) or Antarctic (AA) |
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term
|
definition
As air masses migrate from their source regions,
their temperature and moisture characteristics
are modified by the areas over which they pass |
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condition
|
definition
Warm, humid maritime air mass passes into cooler
continental areas
– Dry, cold continental air masses from polar regions
move south and east over the Great Lakes |
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term
| Air masses eventually lose their initial |
|
definition
characteristics due to migration into areas of
different moisture and temperature
characteristics |
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term
| Atmospheric Lifting Mechanisms |
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definition
Convergent Lifting:
Convectional Lifting:
Orographic Lifting:
Frontal Lifting: |
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term
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definition
| Air flows toward an area of low pressure |
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term
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definition
| – Air lifting stimulated by local surface heating |
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term
|
definition
– Air is forced over a barrier such as a mountain
range |
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term
|
definition
– Air lifted along the leading edges of contrasting air
masses |
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term
|
definition
Air flows from different
directions into the same
low pressure area |
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term
|
definition
Trade winds
converge along the
Intertropical Convergent
Zone |
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term
| Convectional Lifting cont: |
|
definition
Caused by relatively
cooler air mass moving
over warmer land |
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condition
|
definition
Urban heat island
– Area of darker soil in a
plowed field |
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term
Convectional activity
over the |
|
definition
Florida
peninsula; The land
mass of Florida is
warmer than the
surrounding Gulf of
Mexico and Atlantic
Ocean |
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term
|
definition
Mountain acts as a
topographic barrier to
migrating air mass:
– Air forcibly lifted upslope
on the windward side
– Lifting air cools
adiabatically: Precipitation
may result
– Descending air mass on
leeward side undergoes
adiabatic heating and
becomes dryer |
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term
|
definition
| Dry region on the leeward side of mountain referred to as a rain shadow |
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condition
|
definition
Fronts are boundaries
between HIGH PRESSURE
air masses with differing
properties:
The less-dense warm mT air
is lifted up and over the
denser cold cP air: |
|
|
term
Fronts are boundaries
between HIGH PRESSURE
air masses with differing
properties: |
|
definition
– COLD and DRY (high
density).
– WARM and MOIST (low
density). |
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terminus
The less-dense warm mT air
is lifted up and over the
denser cold cP air: |
|
definition
– Frontal boundary is often the
site of storm activity and
precipitation |
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term
|
definition
– Cold dense air pushing low density warmer air
– Cold air forces warm air aloft
– 400 km wide (250 mi)
– Relatively rapid movement
– Convective activity (thunderstorms) |
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term
| Cumulonimbus clouds are commonly associated with |
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definition
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term
|
definition
– Warm low density air pushing cold dense air
– Warm air moves up and over cold air
– 1000 km wide (600 mi)
– Relatively slow movement
– Slow steady rain or snow |
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term
Cirrus clouds followed by stratus clouds are commonly
associated with an approaching |
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definition
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condition
|
definition
Faster moving cold front
overtakes a warm front:
– Two bodies of cold air
associated with each front
collide.
– This forces the warm air
between them to rise.
– Results in uplift of warm air that
is no longer in contact with
ground.
– This uplift of warm air results in
cloud formation even though
frontal system has no contact
with the ground. |
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terminus
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definition
Cold arctic air penetrates
into continental interior
and meets warm, humid air
from Gulf of Mexico along
a frontal system |
|
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term
Life Cycle of a Midlatitude
Cyclone |
|
definition
|
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term
|
definition
Cold And Warm
Air Masses
Converge And Are
Drawn Into Conflict |
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term
Cyclogenesis:
Cold And Warm
Air Masses
Converge And Are
Drawn Into Conflict |
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definition
The rotation of
the earth and the
jet stream aloft
induce spinning
(vorticity) along
the stationary
front |
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term
|
definition
Warm
Air Moves Northward
And Cold Air Advances
Southward |
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term
Opening Stage: Warm
Air Moves Northward
And Cold Air Advances
Southward |
|
definition
Two cold air masses
converge, lifting warm
air mass in between |
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term
|
definition
Occluded Stage:
Cold Air Mass
Overtakes The
Warm Front |
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term
|
definition
Lifting Mechanism Of
Cyclone Results In
Continuous Layer Of
Cooler Air Beneath
Warmer Air |
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term
|
definition
associated air masses move
across the continent along
storm tracks guided by the
jet stream |
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term
|
definition
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term
|
definition
Thunderstorms may develop within an air
mass, along a cold front, or result from
orographic lifting along a mountain slope |
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term
|
definition
Raindrops and ice
crystals form aloft and
descend through the
clouds
Violent updrafts pull
surrounding air into the
cumulonimbus system
Heavy
precipitation,
lightening,
thunder, hail,
strong winds,
and possibly
tornadoes |
|
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term
| How Lightening Possibly Forms |
|
definition
Ice formation process within
cumulonimbus cloud causes
positive and negative
charges to develop on
different- sized water
droplets and/or ice crystals:
– Lighter positive charges rise
while heavier negative charges
sink within the cloud
– Negative charges at base of
cloud repel negative charges
on ground surface, leaving a
net positive charge on ground
– Charge difference is then
neutralized by lightning bolt. |
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term
|
definition
|
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term
|
definition
heat
air to 30,000 oC,
causing rapid
expansion of the
air and
formation of a
compression
wave that we
hear as thunder |
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term
|
definition
Hail generally forms
within a cumulonimbus
cloud |
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condition
|
definition
Violent updrafts pull
surrounding air into the
cumulonimbus system
Raindrops circulate
repeatedly above and
below the freezing
level in the cloud
Circulation
above and
below freeze
level adds
layers of ice to
hailstones until
updrafts can
no longer
support weight
For larger
hail, frozen
pellets must
stay aloft
longer |
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term
|
definition
Derechos are strong linear
winds in excess of 26 m/s
(58 mph) associated with
thunderstorms and bands of
showers |
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term
|
definition
warm, moist air trapped beneath a
ceiling of cold, dense air |
|
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term
| The 7 years from 2003 to 2009 show a |
|
definition
significant increase in the average
number of tornadoes per month |
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Term
|
definition
| 3 second gust wind speed; damage |
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term
|
definition
| 105-177 kmph, 86-110 mph;light damage; branches broken, chimneys damaged |
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term
|
definition
| 138-177 kmph, 86-110 mph, moderate damage beginning of hurricane wind speed designation, roof coverings peeled off, mobile homes pushed off foundations |
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term
|
definition
| 178-217 kmph 111-135 mph; considerable damage roofs torn off frame houses, large trees uprooted or snapped, boxcars pushed over small missiles generated |
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term
|
definition
| 218-266 kmph, 136-165 mph; severe damage roofs torn off well constructed houses, trains overturned, trees uprooted, cars thrown |
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term
|
definition
| 267-322 kmph, 166 200 mph, devastating damage; well built houses leveled, cars thrown large missiles generated |
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term
|
definition
| more than 322 kmph> 200 mph; incredible damage houses lifted and carried distance to disintegration, car sized missiles fly farther than 100 m bark removed from trees |
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terminus
| Formation Of A Mesocyclone |
|
definition
Strong winds aloft flow over weaker winds below;
shear causes spinning along a horizontal axis
Updraft from
thunderstorm
development tilts the
rotating air along a
vertical axis
Mesocyclone forms as a rotating updraft within the thunderstorm;
tornado descends from the lower portion |
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term
| Development Of Cyclonic Motion |
|
definition
Cyclonic motion
begins with slowmoving
easterly wave
of low pressure in the
trade wind belt and
sea-surface
temperatures greater
than 26 oC (79o F):
– Cyclone forms on
eastern side of
migrating trough of low
pressure |
|
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term
| Development Of Cyclonic Motion cont |
|
definition
– Surface air flow
converges into lowpressure
area and rises
– Divergence aloft acts
like a chimney, pulling
more moisture-laden air
into the developing
system
– Wind shear must be
minimal or non-existent
in order to maintain the
vertical, convective
circulation |
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term
|
definition
winds: variable, low
definate area of surface low pressure, patches of clouds |
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term
|
definition
winds: up to 63 kmph (38 mph) up to 34 knots.
Gale force, organizating circulation, light to moderate rain |
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term
|
definition
winds: 63-118 kmph (39-73 mph); 35-63 knots
closed isobars; definite circular organization, heavy rain; assigned a name |
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terminus
| Hurricane (atlantic and east pacific) typhoon (west pacific) cyclone (indian ocean, australia) |
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definition
winds: greater than 119 kmph (74 mph), 65 knots
Circular, closed isobar; heavy rain, storm surgers; tornadoes in right front quadrant |
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term
| what does a hurricane need? |
|
definition
warm ocean water (more than 80 F) provides energy for the hurricane and causes more evaporation making humid air and clouds
Winds coming together force air upwards
Winds flow outward above the storm, allowing the air below to rise.
Humid air rising makes the clouds of the storm. latent heat of condensation provides the energy.
light winds outside the hurricane steer it and let it grow. |
|
|
term
Cross Section Of
Hurricane |
|
definition
• Counterclockwise
rotation in Northern
Hemisphere
• Strong winds spiral
upward in eye wall
• Lowest pressure within
eye where sinking air
produces calm conditions |
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term
|
definition
| wind speed: 119-154 kmph (74-95 mph) 65-82 knots (dangerous some damage) |
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term
|
definition
| 155-178 kmph (96-110 mph) 83-95 knots (dangerous, extensive damage) |
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term
|
definition
| 1954 Hazel; 1999 Floyd, 2003 Isabel (was a cat 5); juan 2004; francis 2008; 2010 alex |
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|
term
|
definition
| winds: 179-210 kmph (111-130 mph) 96-113 knots (devastating damage) |
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|
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condition
|
definition
| 1985 elena; 1991 bob; 1995 roxane; marilyn 1998 bonnie; 2003 kate; 2004 ivan (was a cat 5)jeanne; 2005 dennis; katrina, rita, and wilma (were cat 5); 2007 henrietta; 2008 gustave and ike (were cat 4) |
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|
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term
|
definition
| 211-250 kmph (131-155 mph) 114-135 knots (catastrophic damage |
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term
|
definition
| 1979 frederic, 1985 gloria; 1995 felix, luis, opal; 1998 georges; 2004 charley; and 2005 emily (was a cat 5) |
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term
|
definition
| >250 kmph (>155 mph) > 135 knots (catastrophic damage) |
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term
|
definition
| 1935 no 2: 1938 no 4.; 1960 donna; 1961 carla; 1969 camille; 1971 edith; 1977 anita; 1979 david; 1980 allen; 1988 gilbert, mitch; 1989 hugo; 1992 andrew; 2004 ivan; 2007 dean felix |
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term
|
definition
Out at sea, strong winds pile
up a wall of water near the
hurricane center
Also, low pressure
in eye lifts a dome
of water within eye
As the surge approaches the
coast, the shallowing sea
floor aids in piling up the
wind-driven ocean |
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term
|
definition
Incoming wall of water on
the “dirty” side of the
hurricane can exceed 15
feet in height, causing
tremendous flooding and
damage along the coast
Strong winds blow
seaward on the
“clean” side, creating
an ebb surge |
|
|
terminus
| Galveston Hurricane of 1900 |
|
definition
Category 4 Hurricane struck the Island September 8, 1900 with
wind speeds of over 120 miles per hour. Over 6,000 people killed. |
|
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term
| Galveston Hurricane (Continued |
|
definition
Storm surge and
wind destroyed
much of the city
Hurricane-force waves
and storm surge
pushed a wall of
debris, reaching 15
feet in height, inland
over several blocks
Areas behind
the advancing
wall of debris
stripped clean
of structures |
|
|
term
But why a Category 4
storm surge with Ike? |
|
definition
Ike was an unusually large
hurricane with a large eye, so
winds blew over a tremendous
area of water |
|
|
|
terminus
|
definition
•Reached Category 5 status in Gulf
of Mexico •Made landfall on Louisiana coast
August 29, 2005, as a Category 3
hurricane •Most destructive storm in terms of
economic loss (estimated up to $125
billion) |
|
|
term
| Where is most of the Freshwater on Earth stored? |
|
definition
|
|
term
| What is Relative Humidity? |
|
definition
| Mass of water vapor in air divided by the mass of water vapor that the air can hold |
|
|
term
| What is the following figure showing? |
|
definition
.
The warmer the air, the lower the relative humidity |
|
|
term
| With regard to the following illustration, at what stage is latent heat released and its value negative? |
|
definition
| Water vapor condenses into liquid water |
|
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terminus
| What happens to an air parcel that ascends from near the ground surface to higher altitudes? |
|
definition
| Air parcel expands and cools at higher altitudes |
|
|
term
| What is the following illustration demonstrating? |
|
definition
|
|
terminus
| Which of the following conditions results in a stable atmosphere? |
|
definition
| Rising air parcel has a higher adiabatic rate than the environmental lapse rate |
|
|
terminus
| The conditions below will result in clear skies and stagnant air. |
|
definition
|
|
condition
| The picture below is an example of ____________ clouds. |
|
definition
|
|
|
term
|
definition
| Cool, dense air settles in a valley |
|
|
terminus
| the average rate at which ascending, water-saturated air cools by expansion is called the ______________. |
|
definition
|
|
term
| An air mass classified as maritime polar (mP) will most likely be |
|
definition
|
|
term
| An occluded front forms when… |
|
definition
| Two bodies of cold air collide, forcing the warm air between them to rise so that the latter is no longer in contact with the ground |
|
|
term
| Which of the following statements regarding storm tracts is FALSE? |
|
definition
| Average storm tracts shift northward into Canada during the winter and southward into the U.S. during the summer |
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|
terminus
| Strong thunderstorms, lightening and tornadoes are usually associated with… |
|
definition
|
|
Term
| The figure below illustrates the formation of a _____________ |
|
definition
|
|
terminus
| Which of the following statements is NOT one of the steps leading to hurricane formation? |
|
definition
| Strong wind aloft shears off the top of the developing cyclone |
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|
