Weather Flashcards
4 Atmospheric Levels
Which level does most of the weather occur at?
What is the area that boxes the weather in called?
1)Troposphere
2)Stratosphere
3)Mesosphere
4)Thermosphere
Called the Tropopause
Temperature that results in Higher Pressure
Temperature that results in Lower Pressure
Heat- Higher
Cold- Lower
Troph
Elongated area of low pressure
Ridge
Elongated area of high pressure
Coriolis force increases when you’re close to…
Decreases when you’re close to…
Increases towards the poles
Decreases towards the equator
Does higher pressure mean higher or lower winds
Higher winds
Sea Breeze
Blows from cool water to warmer land
Speeds of 10-20 knots
Exists between 1500 and 3000ft
Land Breeze
Blows from cooler land to warmer water (opposite of sea breeze)
Weaker than the sea breeze
Valley Breeze
Mountain slopes are warmed by the sun during the day
Creates upslope flow few hundred feet above surface
5-20knots
Mountain Breeze
High terrain cools off and eventually becomes cooler than the air over the valley
Develops prior to sunrise
5-15knots
Mouth of valley sometimes sees speeds of 25+ knots
Coriolanus force
Causes all free moving objects to trace a curved path due to the earth’s rotation.
In the northern hemisphere the deviation will be to the right of the intended path.
In southern hemisphere the deviation will be to the left of the intended path.
Lapse Rates
Rate at which temperature decreases with an increase in altitude
Average rate of temp change in 2 Celsius (3.5 Fahrenheit)
Air is stable as long as lapse rate remains below 3 degrees
Air is unstable if it exceeds 3 degrees
Temperature Inversions
What kind of weather does it usually result in?
Happens when temperature increases with an increase in altitude
Occurs in stable air w/ little to no wind or turbulence
Usually results in fog, haze, smoke, low clouds
Humidity
The difference between temperature and dew point
Relative humidity is the actual amount of moisture in the air compared to the total amount that could be there
Dew point
Temperature at which air reaches a state in which it can hold no more water
100% of moisture capacity is called saturation
How do you determine cloud ceiling with dew point and temperature?
Temperature-Dewpoint divided by 2, then multiplied by 1000
Divided by 3.5 if in Fahrenheit
When does frost form?
When water vapor changes directly to ice (deposition) on a surface that is BELOW freezing
Happens when objects cool to a temperature below the dew point
Water vapor then condenses out of the air to form dew, which then turns to frost if the surface is freezing
Types of Clouds
Low
Middle
High
Clouds with vertical development
Low Clouds
Surface to 6500ft AGL
Usually consist of entirely water
Types of Low Clouds:
Stratus
Stratocumulus
Nimbostratus
Middle Clouds
6500-20,000ft AGL
Composed of water, ice crystals, or supercooled water
May contain turbulence and potentially severe icing
Types of middle clouds:
Altostratus
Altocumulus
High Clouds
Above 20,000ft AGL
Generally white to light gray in color
Form STABLE AIR
Composed of mainly ice crystals
Seldom pose serious turbulence or icing hazard
High Cloud types:
Cirrus
Cirrostratus
Cirrocumulus
Clouds with Vertical Development
Bases are fount in the low to middle range and their tops extend to high territory
Puffy white clouds with flat bases that can build into towering, threatening behemoths
Types:
Cumulus
Towering Cumulus
Cumulonimbus
Embedded (in reference to cumulus clouds)
When they’re hidden amongst other cloud formations
When does precipitation occur?
When water or ice particles grow in size until they can no longer be supported by the atmosphere
3 Methods of Precipitation
Deposition (droplets reach max size then fall towards the earth)
Coalescence (bigger drops engulf the little ones on the way down)
Supercooled water droplets (turn to rime when they come into contact with a surface)
Drizzle vs Rain vs Rain Showers
Drizzle is less than .02 inches in diameter
Commonly associated with fog or low stratus
Rain is .02 inches or greater in diameter
Falls at a steady rate and stops gradually
Rain showers start, change intensity, then stop suddenly
Air Mass
Large body of air with fairly uniform temperature and moisture content
Classifications of Air Masses
For temperature: Polar/Tropical
For moisture content: Continental/Maritime
Air Mass: warming from below
Air mass moves over warmer surface
Lower layers of air mass are heated causing vertical movement of the air
EXTREME INSTABILITY
Air Mass: cooling from below
Flows over cooler surface
Lower layers are cooled and vertical movement is inhibited
Stability is increased