NWA Test Flashcards
What “mb” chart is used to determine short waves/long waves (ridges, troughs)?
500 MB
What “mb” chart to find absolute vorticity?
500 MB
Moderate to strong low pressure systems will be driven by the flow at this “mb” level.
500 MB
What “mb” level is at the top of the troposphere and in the lower stratosphere?
300 MB, 250 MB and 200 MB charts
What “mb” level are the jetstream winds and jetstreaks found at?
300 MB, 200MB
What “mb” level for confluence and difluence?
300 MB, 250 MB, 200 MB
What has the highest albedo?
- asphalt
- ocean
- forests
- clear skies
- clouds
clouds (snow has the whitest albedo)
If there are cold air “backing” winds involved with a low pressure system, where will the strongest winds be?
- center
- south
- east
- northwest
Northwest
What kind of advection happens aloft in an ice storm?
- Weak CAA
- Strong CAA
- Weak WAA
- Strong WAA
Weak WAA
What is evidence of an EF0 tornado?
- Catastrophic
- No damage
- Little damage
Little damage
What does the Saffir Simpson scale measure?
1 to 5 rating based on a hurricane’s sustained wind speed
In which direction do a hurricane’s winds go?
- outward only
- inward only
- inward at the surface, outward aloft
- outward at the surface, inward aloft
inward at the surface, outward aloft
What is an example of a short term model?
NAM = 84 hours
What is an example of a long term model?
GFS = 16 days
What does a NPN profile measure and how often?
wind / 15-60 minutes
What does ASOS not report?
- dewpoint
- temperature
- wind
- precip type
- cloud type
cloud type
ASOS tells you everything except…
- precip type
- cloud height
- temp
- dew point
- wind
- none of the above
None of the above
When is hail the most common in the US?
June to August
Where is lightning most common?
Florida
This “mb” chart includes the low-level jet and is useful in identifying frontal boundaries and the rain/snow line?
850 mb
This “mb” chart intersects clouds and weak low pressure systems will be driven at this level and dry intrusions at this level are a precursor to severe weather.
700 mb
What does MOS “not” directly account for?
- Seasons
- Albedo
- Cloud Type
Seasons
What does not directly impact evaporation?
- Strong winds
- Radiation
- Dewpoint
- Relative Humidity
- Isobaric pressure
Isobaric pressure
What is the bright white on water vapor?
higher amounts of moisture
T/F Geostrophic winds move parallel to wind contours.
True
Geostrophic winds move _________ to height lines.
parallel
Winds move towards ______ pressure and are turned because of _______.
low, coriolis
Where would the strongest storm surge be in a hurricane?
- Left of the eye
- Behind the eye
- Right of the eye
- Right of the rear flank downdraft
- Left of the rear flank downdraft
Right side of the eye
where would the strongest storm surge be in a hurricane?
- Left of the eye
- Behind the eye
- Right of the eye
- Right of the rear flank downdraft
- left of the rear flank downdraft
Right of the eye
Do winds generally move across isobars, parallel to or not related to them?
Roughly parallel to isobars
How do infared satellites pick up their information?
through thermal radiation
In the early start of hurricane season, where do hurricanes normally form?
Gulf of Mexico, Bahamas and West Caribbean
What does clear air mode get?
reflectivity and velocity
This radar is used on a sunny day so it only scans the lowest levels of the atmosphere
Uses: Dry wx, very light precipitation, insects, birds, fronts
How do you identify a mesocyclone?
velocity
What is VADS information? (Velocity Azimuth Display)
radar that shows the average horizontal winds on a time versus height chart
How do you tell the direction and speed of a thunderstorm?
looping reflectivity
What chart gives you information on the weather that we are seeing and experiencing?
surface chart
What “mb” chart is the best to assess pure thermal advection?
850 MB
What “mb” chart to indicate relative humidity?
700 MB
How high is the 500 MB level (in feet)?
16,000 - 20,000’
How high is the 500 MB level (in meters)?
around 5,000 - 6,000 meters
How high is the 850 MB level (in feet?)
3,800’ - 5200’
How high is the 850 MB level (in meters)?
1170 - 1590 meters
How many miles is the 200 MB on average?
7.4 miles
How many feet up is the 200 MB level on average?
39,000’
How many miles up is the 250 MB level on average?
6.6 miles
How many feet up is the 250 MB level on average?
35,000’
How many miles up is the 300 MB level on average?
5.7 miles
How many feet up is the 300 MB level on average?
30,000’
How many miles up is the 500 mb on average?
3.4 miles
How many miles up is the 700 mb level on average?
around 2 miles
How many feet up is the 700 mb level on average?
10,000’
How many miles up is the 850 mb on average?
around 1 mile up
How many feet up is the 850 mb on average?
5,000’
What’s the most accurate forecast?
12 hours out
Most accurate numerical modes go out:
- 12
- 36
- 48
- 72 hours
12 hours
What angle is the local solar noon?
- 23.5 N
- 23.5S
- 0 degrees
- depends on latitude
- depends on longitude
Depends on latitude
This is the day every point on earth will have 12 hours of daylight and 12 hours of darkness.
Equinox
On the equinox, the earth’s tilt is perfectly perpendicular to the sun’s radiation, the from the sun’s perspective the earth is tilted neither toward or away from the sun. At the equator, the sun will be directly overhead at ______ on the equinox.
Solar noon
What is subrefraction?
When there’s less bending than normal causes radar to overshoot objects
What is vertically integrated liquid?
Amount of liquid water that the radar detects in a column of the atmosphere for an area of precipitation. High values are associated with heavy rain or hail
What is Vertically Integrated Liquid based off of?
Based on radar returns
When there’s divergence aloft, what is below?
convergence
What is happening aloft of a cold core low?
more intense circulation
In the northern and southern hemispheres, the jet stream comes form the ______ (north, south or west) at _______ (50 MPH or 100 MPH)
west, 100 MPH
What are a hurricane strength’s winds and gale force winds?
Hurricane: 74 MPH
Gale: 39 MPH
What is not a mid-Atlantic state:
- Delaware
- Maryland
- New Joersey
- Connecticut
Connecticut
The earth emits _______ (longwave or shortwave) radiation which is (visible or infared)
longwave, infared
How often is the NPN profiler data available?
15-60 mins
Order of cloud types in a MLC (mid-latitude cyclone) (from first to last)
- cirrus
- cirrostratus
- altostratus
- nimbostratus
- cumulus
- cumulonimbus
Behind front:
- post-frontal status
What is not an MCS?
Supercells
What season is the Azores/Bermuda high the strongest (summer/winter) and what impacts it has on the Eastern US (dry/humid)?
summer, humid
How is the strength of the tornado determined?
- wind only
- damages only
- wind and damages
damages
IF a south wind becomes westerly, is it veering or backing? Also, where would the low pressure be?
veering / north
Where is the jetstream in the winter ?
closer to 300 MB
Where is the jetstream in the summer?
closer to 200 mb
If lightning is observed, with thunder heard 10 seconds later, the storm producing the flash is _________.
2 miles
number of seconds between lightning and thunder / 5 - answer
In non-mountainous regions, one inch of liquid-equivalent precip on average results in approximately ____ inch(es) of snow at most locations for surface temp between 28-32 degrees.
10 inches
10 to 1 ratio
The sun’s rays are perpendicular to the earth’s axis at ____ degrees latitude during the _______.
0, vernal equinox
The earth rotates on a tilted axis of ____ degrees.
23.5
Severe convective wx is favored ahead of or behind a cold front?
ahead of a cold front
radiation fog over a large region is often associated with __________.
radiational cooling and HP
Ice storms are most common ________.
Ahead of warm fronts
Wind flow around a low pressure system in the Northern Hemisphere is ________.
inward and counterclockwise
Precipitation, as depicted on radar imagery does not exhibit ______.
an expanding circular formation with a “clear” center
The appearance of rain and snow on the WSR-88D base reflectivity, when occurring simultaneously is _______.
very similar
What is it called when the radar receives the pulse of energy back at the wrong time and incorrectly detects the distance and plots it in the wrong location?
Range folding
GenMet Data used input for numerical wx prediction models does NOT include________.
previous model output
How often does a radar need to scan a gauge in one hour?
Ideally needs a scan every 2.5 mins.
Visible satellite measures ________.
light reflected back
Infared satellite measures _________.
temperature
If something appears bright on visible satellite ______.
It is thick
If something is bright on infared, it is ________.
cold / high cloud tops
If something is darker on infared, it is ________.
warm / low cloud tops
Visible/Infared satellite only works in the daytime.
Visible
In a midwest MLC, what kind of air mass comes behind a cold front?
cP
In a midwest MLC, what kind of air mass comes in front of a cold front?
mT
In a midwest MLC, what kind of air mass comes behind a warm front?
mT
In a midwest MLC, what kind of air mass comes ahead of a warm front?
cP
What is an NPN?
Noaa Profiler Network
Back in the 90s and early 2000s
put them in the midwest / measured winds
6 min samples of the winds / so every hour
shut it down because of money
When there’s divergence aloft, what is below?
convergence
How do bodies of water impact climate?
Bodies of water take longer to heat up. Coastal communities tend to be warmer during winter and cooler during the summer.
How does elevation impact climate?
The higher up you go, the colder it gets because there is less air
How does latitude impact climate?
The higher up you go, the colder it gets because those areas receive less sunlight
What is the average planetary boundary layer in feet?
3,000 feet
What is the average planetary boundary layer in meters?
1000 meters
Is severe weather likely ahead of a cold front or behind it?
ahead
A mesocyclone is sometimes associated with a ________.
tornado
True or False: a tornado can rotate either counterclockwise or clockwise
true
counterclockwise in Northern Hemisphere
counterclockwise in Southern Hemisphere
According to the NWS, wind damage is expected when convective gusts reach or exceed ________.
58 MPH
A gust front results from _______.
thunderstorm downdraft
Although water vapor counts for _____ percent of the atmosphere by carbon dioxide ____ percent, both represent very important green house gases.
less than 1, less than 1
The ozone layer is found within the ______.
stratosphere
The polar jet is caused by _________ and is typically found ________.
thermal and momentum gradients
at the pole
During the warm season, the daytime planetary boundary layer is hydrostatic due to _____ effects.
unstable, thermal
The moist adiabatic lapse rate is approximately
6 degrees per every 1000 meters
When the temperature within the troposphere decreases more rapidly with height, the atmosphere is said to be ______.
unstable
The albedo of freshly fallen snow is _____ than the albedo of grassy surfaces.
much larger
The absorption of solar radiation by a surface is not a function of __________.
atmospheric pressure
The reduction in visibility due to haze results from ________.
scattering
water vapor in the atmosphere is typically largest in/at the
tropics (equator)
water vapor in the atmosphere is typically smallest at the _______.
poles
Hydrostatic balance is said to exist when two primary vertical forces are in balance. What forces are these?
gravity and vertical pressure gradient
When looking down the pressure gradient, coriolis deflection is to ______ in the southern hemisphere and to the _______ in the northern hemisphere.
left, right
Friction effects may change an air flow’s _____.
speed and direction
Surface divergence occurs within ______ pressure systems, which is generally a result in _______ weather.
high, fair weather
Upper level convergence implies _____ vertical motion and the development of surface _______ pressure.
downward, high
A strongly developing low pressure system is not characterized by which of the following conditions?s
Rising pressure
A high pressure center is not typically characterized by which of the following conditions?
strong winds
Which air mass may originate in the contiguous US?
cP
In the devleoping stages of an extratropical cyclone (mid lat cyclone) clouds and precip typically form _______.
closely ahead and behind fronts
A north to south flow of air is considered to be ______.
meridonial
The primitive equations used in numerical weather prediction models are based on ________.
newton’s law of motion
Visible imagery depicts clouds based on the _____ of shortwave radiation.
reflection
Dark spots or regions on a water vapor imagery generally indicate ________.
subsidence
GOES geostationary satellites ______ at all times.
view the same region
For a typical visible satellite image during the cold season over the US, warm fronts will most often be found ________.
in the middle of a cloud mass
When a lighter grey shading appears over land as compared to the ocean (on IR) it means that _______.
the land is cooler than the water
When considering radar, the term “target” is used to reference to _______.
precipitation
The rate of motion of precipitation returns on radar is based upon ___________.
The distance traveled by echoes over time
Positive and negative radial velocities that exist “gate to gate” (side by side) on a radar indicate _________.
rotation
When observing a thunderstorm cell with another directly behind it, the c-band (3-) will _____.
see the more distant cell to some extent
Radar range for determining reflectivity is not limited by ________.
heavy rainfall
Typical radar systems transmit signals with wavelengths of _____________.
1-10 cm
Clear air mode is “more/less” sensitive than precipitation mode.
More sensitive than precipitation mode
Range folding usually occurs within a distance of about _____ downrange from the antenna.
more than 50 miles
A bright band on the radar is often indicative of ______.
change in precipitation
The intensity level of precipitation on radar is represented by what?
expressed by dbz
Ground clutter can often by identified through ______.
looping the radar
A VAD wind profile provides _______.
a time plot of wind direction and speed
Super refraction causes a radar beam to be ______ .
bent more
T/F: When there is a heat wave in the SW US, there’s a low at the surface and high aloft.
False
ASOS are used for ______.
Most major airports
Isentropic analysis is primarily used to ______.
assess vertical motions
Ground based profiler primarily measures vertical________ profiles.
wind
In the Northern Hemisphere, the earth is closest to the sun in ___________.
January
The sun’s noontime angle of incidence is larger/smaller during the summer?
smaller
The rain/snow ratio may be as large as ________
30:1
For every second between lightning flash and the audible sound of the thunder producing the discharge is approx ____ away.
5 seconds per a mile
Flash flooding is most common in the U.S. during _______.
April, July and August
Air quality standards are based on ________.
the impact on certain chemicals on humans
The desert southwest mainly refers to _________ and _______.
Nevada and Arizona
What is the zero zone (where winds are perpendicular to the radar and radial velocity is zero) known as?
zero isodop
What is an analemma?
Plot or graph of the position of the sun in the sky at a certain time of day at one location throughout the year that has the shape of a figure 8
Gradient wind around high pressure is _________ than the geostrophic wind.
Faster
Where in the atmosphere does density decrease more rapidly?
troposphere
Snow or rain on radar dome…what does it do?
- Increase sensitivity
- Decrease sensitivity
- or disrupt scan
decrease sensitivity
Visible satellite image of Florida and asked whether a sea breeze or land breeze was occurring.
Sea breeze during the day from sea to land.
Land breeze at night from land to sea.
If you are fishing in a stream in a valley and the wind is blowing upstream, is there a valley breeze or mountain breeze?
valley breeze
What does the ZR relationship help to identify? Identifying echo tops or finding mesocyclones?
Identifying echo tops
Z is for reflectivity R for rain rate.
WHich has more thunderstorms?
- Mt
- Ct
Maritime tropical
Which climate has the best chance of seeing thunderstorms?
- cT
- mT
mT
T/F Gust front remnants can last for days?
True
How long does a gust front last?
mins to hours even over 24 hours
How is virga identified?
precipitation and clear air mode
Where is virga detected on radar?
- Clear air mode only
- precipitation only
- both
both
Where are severe storms more UNLIKELY?
- Along a cold front
- at the triple point
- Along a warm front
- Behind a dry line
Behind a dry line
T/F GFS explicitly produces convective forecasts
False
Lifespan on a TVS (tornado vortex signature)
exam output every 6 min can be used to assess the depth and persistence of a mesocyclone
How long radar on average does a TVS last?
1-2 radar scans (as we roughly know 5 mins per a scan)
When is Bermuda-Azores high the strongest and what is the pressure?
Summer, central pressure hovers around 1024 mb
What is lee troughing?
stretching of column of air as it descends on the lee-ward side of highly elevated terrain such as rocky mountains
What is lee cyclogenesis?
Development of a cyclonic circulation on the downwind side of a mountain.
Why is GOES the distance it is from Earth?
Satellite can constantly monitor the same area of the earth
What happens to temperature in the troposphere as you go up?
temps get colder with height
What happens to temperature in the stratosphere as you go up?
temps get warmer with height
What happens to temperature in the mesosphere as you go up?
temps get colder with height
What happens to temperature in the thermosphere as you go up?
temps get warmer with height
How do you spot a mesocyclone?
- Velocity
- Doppler Radar
- or Someone at the Ground
How far does the NAM model go out?
48-84 hours
How far out does the GFS go?
360 hours or 16 days
HOw far out does the Euro go?
10 days
This occur when the temperature decreases with height of greater than 10 degrees celsius per kilometer.
Superadiabatic lapse rate
What is the dry adiabatic lapse rate?
around 10 degrees celsius per 1000 meters
Explain greenhouse effect
- During the day, the sun heats earth’s surface
- At night, the earth emits heat back into the air
- Some of that heat is trapped by the gases in the atmosphere - keeping our earth warm (59 degrees F on average)
What is the three body scatter?
Hail spike
spike of weak reflectivity that extend out from t-storm
Best way to nowcast rain/snow using radar when they are occurring at the same time?
Rain is more organized
snow is more fuzzy
When a wave of light strikes an object and bounces off it is called ___________.
reflection
When a wave of light passes through one object to another, causing it to bend, it is called ___________.
(Like air to water: if you look at something in the pool, it will look bent)
refraction
All the sun’s radiation that enters Earth’s atmosphere must eventually be sent back to space to maintain a constant global average temperature - this is called…
Earth’s energy balance
What percentage of total incoming solar radiation do molecules, aerosols and clouds in the atmosphere absorb?
23%
How much incoming solar radiation is absorbed at the earth’s surface, land and ocean?
almost half
How much solar radiation is reflected back to space by air, clouds and the earth’s surface?
30%
What is a hurricane warning?
Hurricane conditions (sustained winds of 74 MPH or higher) are expected in the area Issued 36 hours ahead of when TS force winds will impact an area
What is another name for a gust front?
outflow boundary
What is a variable gas in the atmosphere?
water vapor
or also aerosols and ozone
What levels of the atmosphere does water vapor use?
middle and upper levels of atmosphere
Above the troposphere there is very little moisture
Why can’t water vapor see the lower levels of the atmosphere?
Water vapor in the middle and upper levels block the detection of the lower atmosphere
What are raindrops that freeze once it hits the surface?
Freezing rain
How do ice storms wind down?
evaporative cooling
Does evaporative cooling absorb latent heat?
Yes
How does evaporative cooling absorb latent heat?
With the removal of heat from the air, the air cools
Why is height is used in the upper levels of the atmosphere?
because pressure and density vary
What does closely packed isobars mean?
winds are stronger
Why ageostrophic winds occur at the surface?
Friction
Why are GOES satellites placed where they are?
Earth’s gravitational pull with centrifugal force
What can’t radar pick up on?
clouds
How often is MOS data released?
2 times a day
Identify reflectivity and velocity on radar.
Velocity: red/green
reflectivity: rain/snow, etc
Wind speed for a hurricane
74 MPH - 156 MPH ( cat 5)
Gale force winds =
39 MPH - 54 MPH
How far in advance is a hurricane warning issued?
36 hours
Nexrad radar can determine what on current weather?
a. ) location of precip
b. ) the phase or type of precip
c. ) the intensity of precip
d. ) the movement of precip
e. ) the temp of precip
a. ) location
c. ) intensity
d. ) movement
Which types of radar can scan different sectors within its range and multiple sectors simultaneously?
Phased array radar
What is the cone of silence?
What the radar can’t see because the storm is either over the radar site or super close to it making the radar show a black hole of missing data
The speed of the wind toward or away the radar
base velocity
What kind of reflectivity?
“The intensity and location of precipitation near the ground”
base reflectivity
What type of reflectivity?
“The most intensely precipitating portions of a nearby system”
composite reflectivity
What type of reflectivity?
The movement of precipitation over time
base and and composite reflectivity
Explain: There is an intense thunderstorm containing large hail 16 km (10 Mi) east of a military radar used to monitor aircraft. Another thunderstorm with reports of large hail is 40 km (25 mi) farther east. The forecaster on duty did not issue any statement or warning about the hail from the easternmost storm because reflectivity values for that storm were too low to indicate hail. What phenomenon likely caused this discrepancy?
Attenuation. Because of attenuation, storms close to the radar are better sampled than storms far from the radar site.
Explain: You are walking home and it looks rainy. You call your friend who is on forecasting duty to ask if you will get soaked. She says that according to the reflectivity image, it is currently raining right where you are. You tell her it is not raining anywhere that you can see- there are just some dark clouds above. What do you think caused this discrepancy?
Your forecasting friend was most likely looking at composite reflectivity and not base reflectivity. Composite reflectivity shows the strongest reflectivity within the radar range, and is a mistake to interpret it as showing what is happening at the surface. If your friend was looking at base reflectivity, the precipitation would have evaporated before hitting the ground.
What factors enhance the radar reflectivity around the melting level?
- Drops get bigger
2. When drops melt and develop liquid coating
For NEXRAD WSR-88D weather radars to correctly measure reflectivity, the targets should be much (larger or smaller) that the wavelength of the emitted pulses.
Smaller
Why can two different radars obtain differing reflectivity values for the same location and time?
Radars are in different distances away from the the location.
In which of the following instances would precipitation often go completely unobserved by NEXRAD-WSR-88-D radar due to the geometry of the radar beam?
A. A low, stratiform cloud producing rain near the radar’s max.
B. unambiguous range
C. rain behind a mountain located 10 km (6mi) from the radar
D. Behind a cumulus cloud
Everything besides D
When targets are moving _______ (perpendicular or parallel) to the radar beam, the velocity is recorded as zero.
Perpendicular. Must be toward or away the radar to be measured
Aliasing occurs when the radial velocity exceeds the radar’s maximum unambiguous velocity.
True
What usually constitutes ground clutter that we often see near the radar?
a. ) insects
b. )birds
c. )large particulate matter, like dust
d. ) fog
e. ) local features such as buildings or trees
a. )
b. )
c. )
e. )
Which of the following phenomena appears on radar as evenly scattered bands of weak reflectivity or ripples near the radar, especially during the afternoon?
horizontal convective rolls
ORDINARY thunderstorms happen when…
a. warm sector of midlatitude cyclone
b. backside of a low pressure system
c. edges of high pressure system
d. frontside of low pressure system
e. along locally heavy terrain
Everything besides frontside of low pressure system
Characteristics of ___________ thunderstorm:
short-lived, generally not severe
reflectivity: small, circle shaped echoes with a core of stronger reflectivity
velocity: no particular pattern
Ordinary Thunderstorm
Super cell thunderstorms usually develop:
a. ahead of a warm front
b. ahead of cold fronts
c. along the warm front close to the center of the low
d. along drylines
b. ahead of cold fronts
c. along the warm front close to the center of low pressure
d. along drylines
What type of thunderstorm:
- Long-lived
- large, single cell of very strong convection
- hook echo on reflectivity
- couplet on velocity
Supercell Thunderstorm
What is a long-lived, big mass of storms?
MCS (mesoscale convective system)
low or no no reflectivity in the eye
high reflectivity in the eye wall
high reflectivity bands spiraling outwards
rotation within strong cells in the right front quadrant
These are all characteristics of a _______________:
Tropical Cyclone
Which of the following usually indicates that snow is occurring on a radar return?
a. ) weak banded features
b. ) grainy texture
c. ) low reflectivity values
a. ) weak banded features
b. ) grainy texture
During the winter, what latitude are the polar and sub tropical jets?
polar: midlatitudes, dips southward
subtropical: slower than polar at 25 degrees latitude (in both hemispheres) at an altitude of 8 miles
What is the most deadly weather-related event
Flooding, but heat takes more lives than flooding annually
What kind of coordinate system a specific computer model uses?
ETA?
SIgma?
ETA: step mountains
Sigma: terrain following
How do you know if hail is 1” + in a storm?
a. ) Tbss
b. ) low vil values
c. ) hook echo
TBSS (Three-body scatter spike)
When the dew point and wet bulb temps are the same, ____________________.
The air is saturated and rh is 100%
What does the lifted index compare?
Difference between the 500 MB parcel temp and the actual temp at 500 MB.
Anything negative is unstable, anything positive is stable
What time of day would an air mass t-storms most likely develop?
mid-afternoon
How often are hurricane names recycled?
every 6 years
If you are fishing in a valley and the wind is blowing upstream, is there a valley breeze or a mountain breeze?
valley breeze
When the mid lat cyclone is in the equivalent barotropic phase, this means that __________________.
a. ) The surface low deepens
b. ) The system deepens
c. ) The cyclone is vertically stacked and occluded
d. ) all of the above
c.) vertically stacked and occludes
Where is the subtropical jet located?
between 20 and 40 degrees
Where is the location of the polar jet stream in winter?
Winter: 30
Summer: 60
Where is the tropical storm least likely to form?
- Ivory coast
- Yucatan Peninsula
- Caribbean
- Atlantic Coast
Ivory Coast
What is a variable gas in the atmosphere?
water vapor…up to 4%
Is the mature stage of a cyclone occluding or strengthening?
Strengthening (occluding is the final stage)
A clockwise turning of the wind with height is termed __________________ while a counterclockwise turning of the wind with height is termed ___________.
veering
backing
What does radial velocity not help with?
- divergence
- convergence
- mesocyclone
- intensity of circulation
- intensity of falling precipitation
intensity of falling precipitation
If rain hits the radome, what does it do?
- increase sensitivity
- decrease sensitivity
- disrupt radar scan
decrease sensitivity
What shape is ground clutter?
- circle
- triangle
- donut
Donut
What is the FOUS interval?
6 hour intervals from 6-48 hours
Is fog….
- cooling
- moisture advection
- or both
both
??On average, how thick is the PBL during the afternoon vs. the early morning?
Daytime: 1-3 km
Morning: ?
Which would not enhance air pollution dispersion?
- High Pressure
- Low Pressure
High Pressure (seals in pollution)
Which would not decrease depth of snow on ground?
- Ablation
- Evaporation
- Melting
- Condensation
- Below Freezing Temps
Below Freezing Temps
Which would not enhance lake effect?
- Anticyclonic motion
- Cyclonic Motion
Anticyclonic
Which helps increase hail?
- Large buoyancy
- src wind
- moisture convergence
- pressure fall
Large buoyancy
All the following are cirrus type clouds except:
- Mackerel sky
- Mare’s tails
- Anvil
- Fractus
- Unicus
Fractus
Which is not a low level cloud?
- Fractus
- Cumulus Humulis
- Alto Cumulus
- Stratus
Altocumulus
If the precipitation went from snow, to sleet, to freezing rain, then rain, which one of these just passed?
- cold front
- Warm front
warm front
When latent heat is absorbed, the surrounding environment…
- heats
- cools
cools
These are both warm core lows:
- Anticyclone, hurricane
- Midlatitude cyclone, thermal heat low
- hurricane, thermal heat low
- nor-easter, mid-latitude cyclone
Hurricane, thermal heat low
A sign that a cold core low is maturing and can undergo further intensification is when it tilts toward the cold air with height.
- True
- False
True
All the following terms mean planetary boundary layer except:
- Friction layer
- Surface wind layer
- Boundary layer
- Free atmosphere
Free atmosphere
When winds are light, the Planetary Boundary Layer will:
- Expand
- Contract
Contract
This chart will have the most data available for the operational meteorologist to interpret:
- Surface
- 850 mb
- 500 mb
- 300 mb
Surface
All the following charts have height contours except:
- surface
- 850 mb
- 500 mb
- 300 mb
Surface
This occurs when the downstream wind speeds are faster than the upstream wind speeds:
- Rising air
- Sinking air
- Convergence
- Divergence
Divergence
This is a region of high heights:
- surface high
- shortwave
- ridge
- trough
ridge
If the height contours are parallel to the isotherms, a forecaster would expect:
No thermal advection to take place
A height contour is also known as an __________.
- isodrosotherm
- isotach
- isobar
- isohyet
- isohypse
isohypse
The strength of thermal advection is determined by the spacing of height contours, the spacing of isotherms and _________.
The angle the height contours and isotherms interact
This side of a shortwave is most likely to have uplift, clouds and precipitation:
- Right side (downstream of shortwave axis, exit sector)
- Left side (upstream of shortwave axis, entrance sector)
Right side
A region with sinking air and warming of an air mass is most likely to experience:
- positive vorticity advection
- ridging
- troughing
- upslope flow
Ridging
A shortwave that has temperature advections associated with it is a ____________ shortwave.
- Barotropic
- Baroclinic
Baroclinic
This quadrant is in the entrance sector of a jet streak and dynamic lifting is favorable:
- Left front
- Right front
- Left rear
- Right rear
Right rear
What does the ZR relationship do to help forecasters?Does it help with identifying echo tops or finding a mesocyclone?
Helps identifying rainfall rates - helps with mesocyclone detection
Does water vapor imagery account for water vapor in all levels of the atmosphere?
No. Mid-upper levels of the atmosphere
During Spring, a fast-moving cold front would bring what clouds in what order?
cumulonimbus/cumulus
stratocumulus/stratus
clear skies
What does radial velocity measure?
- motion
- speed
motion
You’re in OK city and a strong low is moving from TX to Chicago. As the low moves the wind will be ________ first, then ________, then _________.
NE
NW
SW
Which of the following would not be associated with a cold core low?
- cold front
- warm front
- cold air aloft
- occluded front
occluded front
Where is hail most common?
- Mississippi
- Colorado
Colorado
All mesoscale convective complexes are mesoscale convective systems.
True
Rising air on the synoptic scale can occur due to either:
low level warm air advection or upper level divergence
As a parcel of air sinks dry adabatically, it will ___________.
- warm
- cool
warm
Fog formed by cooling of the earth’s surface at night is:
- radiation fog
- advection fog
- steam fog
- frontal fog
radiation fog
This is a horizontal transport of air (fairly parallel to earth’s surface or a pressure surface):
- Convection
- Advection
- Subjection
- Objection
Advection
This is a temperature increase with height:
- hydrolapse
- inversion
- steep lapse rate
- superadiabatic lapse rate
inversion
An isotach is a line of constant:
- temperature
- dewpoint
- wind speed
- height
wind speed
The tilt of a trough that often indicates greater instability is:
- negatively tilted trough
- poistively tilted trough
- neutrally tilted trough
negatively tilted trough
Another term for a short wave trough is a(n)
- open wave
- closed low
- cut off low
- barotropic trough
open wave
A spin-up is:
- frontolysis
- frontogenesis
- an increase in rate of rotation
- a decrease in rate of rotation
an increase in rate of rotation
What is the angle of the Earth’s axis?
23.5 degrees
An occluded mid-latitude cyclone will:
- tilt significantly with height
- strengthen rapidly
- Have strong cold and warm fronts connected to the center of circulation
- have a vertically stacked structure
have a vertically stacked structure
This is a wind that turns clockwise with height and is associated with warm air advection:
- backing wind
- veering wind
veering wind
How does water vapor decrease in lower atmosphere?
- rain
- condensation
- surface divergence
condensation
What would not cause refraction?
- low sun angle
- Clouds
- Winds
winds
What causes the movement between air masses?
- PGF
- centrifugal force
- acceleration from one mass to another
- density differences
density differences
What does ASOS stand for?
automated surface observing system
You’re at a fixed point. The wind is initially from the north, then the northwest-what direction is the low moving relative to you?
low pressure to your left so northeast
What is the process in which the wind blows from a region of cold air to a region of warmer air?
cold air advection
What is the process in which the wind blows from a region of warm air to a region of cooler air?
warm air advection
What are localized regions of very fast winds embedded within the jet stream?
jet streaks
What percent of visible radiation is transmitted through a transparent atmosphere?
44% visible
47% infared
Layer of atmosphere: This is the lowest level of the atmosphere that runs from the surface to around 10 km?
Troposphere
Layer of atmosphere: This is the most unstable layer because temps decrease with height, allows for mixing.
Troposphere
Layer of atmosphere: This is often thought of as the mixed layer.
Troposphere
Layer of atmosphere: The second-lowest layer of the Earth’s atmosphere.
Stratosphere
Layer of atmosphere: On average, this layer runs between 10 km & 50 km above the surface.
Stratosphere
Layer of atmosphere: Very stable layer because temps increase with height, the does not allow for mixing.
Stratosphere
Layer of atmosphere: Ozone layer is in this layer
Stratosphere
The _______ layer helps absorb the sun’s energy and warm the temps through the layer.
Ozone
Layer of the atmosphere: The layer of Earth’s atmosphere immediately above the stratosphere.
Mesosphere
Layer of atmosphere: Air density is very low and temps are extremely cold.
Mesosphere
Layer of atmosphere: Temps decrease with height , but density is so low weather cannot take place
Mesosphere
Layer of atmosphere: Last layer of atmosphere.
Thermosphere
Layer of atmosphere: Blends with outer space.
Thermosphere
________ models gives a stations:
- expected precipitation
- relative humidity
- synoptic lift
- instability
- surface wind
- standard 1000-500 mb thickness
- low level temps profile
FOUS
Atmospheric composition: _______% nitrogen
78%
Atmospheric composition: ______% oxygen
21%
Atmospheric composition: ______% argon
1%
Atmospheric composition: ______% Co2 and Water vapor
Less than 1%
Most blizzards in the US occur in which region?
The Great Plains
What is a mT air mass?
Maritime tropical air mass
Warm, moist, usually unstable
What is a mP air mass?
Maritime Polar
What is the source region of the mP air mass?
cold ocean currents or high latitude ocean waters
What is a cP air mass?
The continental polar air mass
low dewpoints, cold temps, and high degree of stability
Air mass: This air mass helps create sfc highs and troughs aloft
cP air mass
What is a cT air mass?
Continental tropical air mass
warm, dry, unstable air
What is the source region of a continental tropical air mass?
Desert southwest, High Plains and Mexico
What happens if a cT air mass moves over mT air mass?
Severe weather increases
What is a boundary that separates cT and mT?
dryline
What 2 locations are the source region of an arctic air mass?
Canada and Siberia
This air mass is similar to cP but it has even lower dewpoints
Arctic air mass
What typically has a leading line of strong convection, trailing region of widespread precipitation and bow shaped segments of intense precip in leading convection?
MCS
Mesoscale convective complex
When cooler air at the ground interacts with warm, humid air at around 1500-3000 feet more collision occurs which usually leads to ___________.
MCS
One of the biggest threats with an MCS is ___________.
Damaging straight line winds
What is the balance of the pressure gradient force and the opposing gravity force?
Hydrostatic Balance
During the cold season, pressure _______ with height, this creates an area of high pressure at the surface and a a trough aloft.
decreases
During the warm season, the troposphere is hydrostatically __________.
unstable
What are the 3 ice growth processes?
diffusion deposition
accretion (riming)
aggregation
ice growth process: __________ occurs due to differences in saturation vapor pressure in water vs. ice.
Diffusion deposition
Diffusion Deposition: Water vapor moves from high pressure to low vapor pressure, thus _____ grows at the liquids expense.
ice
Ice growth Process: _____________ occurs when ice crystals collide with supercooled droplets.
Accretion (riming)
Ice Growth Process: During _______ droplets freeze on contact.
Accretion (riming)
Excessive riming can lead to _________.
graupel (snow pellets)
Ice Growth Process: _______ occurs when ice crystals grow and collide, then stick together. (2 ice crystals sticking together)
Aggregation
Ice Growth Process: This process forms larger snow flakes.
Aggregation
The process by which airstream tends to stretch, leading to frontogenesis.
Deformation
The intensification of a front
Temp gradient is more compact; isotherms closer together in the region the front is developing
Frontogenesis
The weakening of a front
Frontolysis
Results from the release of conditional symmetric instability.
Slantwise convection
What are the 3 types of fog?
Advection fog
West Coast fog
Steam fog
Fog: What is the cooling of moist near-surface air by dynamic processes?
dynamically forced fog
Fog: What type of fog my contain advection and vertical mixing?
Dynamically forced fog
Fog: What kind of fog occurs when an air mass cools to the saturation point as it moves over a colder surface?
Advection fog
Fog: What kind of fog occurs by advection of warm, moist air over cold surfaces?
Advection fog
Fog: What kind of fog forms in regions with high SST gradients?
Ocean fog
Fog: What kind of fog can occur in high wind situations because of more stable PBL?
Maritime fog
Fog: ________ development, day-to-day variations and spacial distribution depends on small changes in PB.
West Coast fog
Fog: Surface cooling is typically absent.
West Coast Fog
Fog: Dominated by oceanic subT high pressure systems.
West Coast Fog
Fog: ______ occurs in high latitude oceanic environments.
Steam fog
Fog: For ______ fog to occur, it is neccessary for rapid saturation to occur WITHOUT any significant air temp change.
Steam fog
Fog: ________ fog happens mainly in winter.
Steam
This happens when winds push surface water offshore.
Upwelling
Upwelling: What happens to the colder water during upwelling?
It rises to the surface, cooling the surface and the lower BL
3 steps for Lake Effect Snow
- Cold air flows over water water
- Cold air is heated and moistened creating an unstable lapse rate
- Convective snow bands develop and are enhanced due to frictional convergence
When forecasting lake effect snow, look for __________, ______________, ____________.
- Temp gradient between cold air and warm water
- Topographic features
- wind direction and speed
Lake Effect Snow: For heavy snow, lake fetch greater than ________.
100 km
Lake Effect Snow: For light snow or no snow, lake fetch less than ______.
30 km
Wind direction determines __________.
fetch
What is it called when:
Wind over water moves faster due to lack of terrain, when it encounters slower moving air over land –> lifting occurs
Frictional Convergence
Lake Effect Model:
- cold air over warm water
- Conduction + latent heat of condensation
- Latent heat of freezing
- convergence due to increased friction over land
- Big lake effect snow
- steam fog on lake surface
- convection clouds
- orographic lifting
Polar Low predevelopment conditions
- A cold outbreak producing a flow of arctic air
- formation of enhanced convection and low level vortices in the cold air mass
- formation of shallow baroclinic zone
What is: Thermally forced circulation along coastal boundaries?
Sea breeze
Sea breezes occur _______ to Autumn when land becomes warmer than the ocean.
Spring
Sea breeze: Brings ________ air from sea inland as a mini front.
colder
Sea breeze: Typically the focus for _____________.
convection
What is the science that deals with the measurement and description of the physical features of the oceans, seas, lakes, rivers and their adjoining coastal areas with reference to their use for navigation?
hydrography
What jet develops in Western Africa during summer due to large surface temps and moisture gradient?
African Easterly Jet
During late summer, this jet exhibits both barotropic and baroclinic instability.
African Easterly Jet
What helps develop African Easterly waves?
African Easterly Jet
What can develop in tropical waves?
Tropical Storms
What is a warm core, non frontal low pressure system that develops over the ocean and has definite organization and structure?
Tropical Cyclone
Lake Effect Snow: Vertical extent is limited by _________ __________.
Capping inversion
