Air Masses Flashcards
When do air masses happen?
When parcels of air stay over a particular location for a while
What is the definition of an air mass?
A large body of air around 1000 miles or more across that has similar properties of temperature and moisture in the horizontal
Air masses are usually ____ pressure
High pressure with little to no wind and movement
An air mass can be one of three temperatures. What are they?
Warm (Tropical)
Cool (Polar)
Cold (Arctic)
Depends on the regions over which the mass gets stuck
Depending on if an air mass is hanging out over the water or land, what is it called?
Continental or Maritime
What are all the combinations or air mass names an air mass could have based on its temperature and whether its over water or land?
Continental Arctic/Polar/Tropical
Maritime Arctic/Polar/Tropical
Abbriviated as cA / cP / cT etc
What are the 5 main air masses that affect Canada?
- mA
- mP
- cA
- mT
- cT
The Source Region of an air mass will always occur in an area of ____ pressure
High pressure
What kind of weather is associated with an air mass?
Even tho the moisture and temp are uniform does not mean it will be devoid of weather.
The weather in a mass will depend on:
* Its moisture content
* Stability
* Any cooling or heating processes present or introduced
The weather happening in an air mass has nothing to do with the properties of an air mass because…?
The properties are that it is uniform in pressure and temperature in the horizontal.
The weather happening within the mass is dependant on a bunch of factors
From north to south, what are the most common types or air masses in Canada?
cA, mA, mP, mT
Properties of Continental Arctic air mass
- Cold and dry
- Rarely form in summer due to 24 hour daylight warming
Properties of maritime arctic (mA) air mass
- Cold and wet
- Dominate in winter
- Can actually form over land in the north in the summer because there are so many gd lakes that it might as well be the ocean
What are the charateristics of a stable air mass?
- Poor vis
- Layer clouds
- Steady precip
- Steady winds that can change a lot with height
- Smooth flying
Characteristics of unstable air mass
- Good vis
- Convective clouds
- Showery precip
- Gusty winds
- Turbulence
As an air mass moves from one source region to another, it will be modified through…
Either heating (causing instability) or cooling (causing stability) from below.
An air mass that is warmed from below will always become more _______
Unstable.
How will weather charts depict an air mass that is being warmed from below?
An additional script of k (cAk)
How do weather maps depict an air mass being cooled from below?
With w. (mAw)
When two different air masses colide, the boundary between them is known as a ____
Front
A common exam question is for them to ask what kind of air mass will replace another as it moves north or south. For this, what do you need to remember?
Remember the order of air masses that are most common from north to south and use this map.
An air mass is always topped by the ___________
Troposphere
The warmer an air mass the ____ the tropopause will be over that area
The higher it will cause the level of the tropopause to be
This also means that the temp at the tropopause will be colder over warmer air masses (because the tropopause will be hgiher)
On a 250 millibar weather map what is important to remember about the L and Hs on it?
They’re not depecting high and low pressure but high and low collumns of air
The air mass that is responsible for bringing Canada cool, damp weather is….
Maritime Polar
The air mass that brings clear and nice wx to the praries is….
Maritime Arctic.
Moist air comes off the pacific and then looses moisture as the air mass moves over the rockies, then brings the dry air into the praries
