Meteorology- Dynamics of Weather Flashcards
What is the primary cause of weather?
Variations in solar energy on the earth’s surface.
What is adiabatic temperature changes?
Temperature change when no heat is added. The temperature change is caused by pressure only
What is the unsaturated air flowing upslope cooling rate?
3 C per 1,000 feet
What is a Katabatic wind?
Wind that flows downslope becoming warmer and drier.
What is another word for anti-cyclone?
High pressure area
Air movement in a high pressure area?
Downward and outward
Air movement in a low pressure area?
Inward and upward
Why do the winds on the ground move straight from high to low pressure? Why do the winds aloft move in a circular pattern?
Surface friction
Coriolis effect
What is an elongated area of low pressure called?
Trough
What is a dryline?
A difference in dewpoint on each side of the line (dry air on one side, moist air on the other side)
Where are the strongest winds in a jet stream?
On the polar side of the jet stream.
How many jet streams are there?
Three, the polarfront, subtropical, and polar night
The tropopause is generally found when the free air temperatures are…
between -55C and -65C
If the atmosphere is getting colder than standard, is the atmosphere stable or unstable?
It is unstable.
Temperature inversions only exist in what type of atmosphere?
A stable atmosphere
What is a ground based temperature inversion?
Terrestrial radiation on a clear, relativity calm night
Where do cloud bases form?
Where the dewpoint lapse rate and the adiabatic lapse rate converge.
In what conditions do you get radiation fog?
Warm, moist air, clear sky, no wind, small temperature/dewpoint spread
What is advection fog?
Warm, moist air, moving over a coastal surface (coastal areas in the winter time)
What is lake fog?
Warm air flowing over a cold lake forming fog on the leeward side of the lake.
How does frost form?
Temperature of the collecting surface is below the dewpoint of the surrounding air and the dewpoint is below freezing.
What is so dangerous about supercooled liquid?
It freezes as soon as it strikes an object.
What do ice pellets at altitude mean?
There is freezing rain above your altitude. The freezing rain has turned to ice pellets.
If you are flying through wet snow, what does that mean?
The air that you are flying through is above freezing.
When does the minimum temperature of the day usually occur?
1 hour after sunrise
If you are getting light rain or greater, how thick must the cloud layer be?
At least 4,000 feet.
What is precipitation induced fog?
Fog resulting from relatively warm rain falling through cooler air.
What are the three basic stages of a thunderstorm?
Cumulus stage- predominantly updrafts
Mature stage- updrafts and downdrafts. Beginning of this stage is signaled by rain falling
Dissipating stage-predominantly downdrafts
How high should you fly over a thunderstorm?
At least 1,000 of altitude for each 10 knots of wind at the top of the thunderstorm.
What is a severe thunderstorm?
Surface winds 50 knots or greater
and/or
Surface hail 3/4 inch or more in diameter
What is the maximum strength of downdrafts in a microburst?
6,000 fpm
What is the life cycle of a microburst?
Not more than 15 minutes
What do the following terms mean in terms of time:
Occasional
Intermittant
Continuois
Less than 1/3 of the time
1/3 to 2/3 of the time
Happening more than 2/3 of the time
Occasional light chop
Slight, rapid, somewhat rythmic bumpiness
Light turbulence
Momentarily causes slight, erratic changes in altitude and attitude
Moderate turbulence
Causes altitude and attitude changes
What is a rotor cloud?
It is the lowest cloud, in the group of clouds associated with the mountain wave.
In order for it to be called a hurricane, how fast must the sustained winds be?
65 knots or more
