idea
Air masses
Air mass is usually a uniform body of air with similar characteristics of temperature, humidity and pressure. They can cross 100s of kms.
An air mass can break from its forming body, and transport its characteristics. (e.g. an air mass can move from the golf of mexico and travel north, bringing hot and dry air to NY).
Classification based on where they form:
- Air masses formed over land are called continental and are dry
- formed over sea are called maritime and are moist.
Classification based on the region:
- Tropical are hot and usually originate from deserts
- Polar are cold
=> Maritime Tropical (Mt), Maritime Polar (Mp), etc.
Fronts
Warm and cold air masses typically alternate. The limit between those air masses are called front. Fronts are typically accompanied by unstable conditions characterized by storms and precipitation.
Fronts are named after the type of airmass overtaking the other one. Cold front = cold airmass displacing a hot airmass.
Signs of a front are distinctive based on the cloud patterns and wind. They are also accompanied by rapidly shifting temperature.
Warm fronts (low pressure) look like a wedge. It's harder for the hot air to displace the cold air:
![[Pasted image 20240717171116.png]]
Warm fronts move slower than colds fronts and are associated with precipitations.
![[Pasted image 20240717171403.png]]
Warm fronts are often associated with stratus and precip. Cold fronts generate cumulus.
Occluded fronts happen when a cold or warm front happens on top of another pair of cold air masses. In this case it's everybody's guess what happens.
links
references
Backcountry skiing / 202409301600-weather--fronts.pdf