Weather Flashcards
Lapse rates
Standard lapse rate: 2°C per 1000 feet
Dry adiabatic lapse rate: 3°C per 1000 feet
Moist adiabatic lapse rate: 1.1-2.8°C per 1000 feet
Standard pressure lapse rate: 1” per 1000 feet
What is necessary for cloud formations
Condensation nuclei
Moisture
Small temperature/dew point spread
Standard temperature and pressure
29.92 inches of mercury at sea level
14.7 psi
1014 millibars
15°C
High pressure system
- Air is more dense
- Flows clockwise, down, and out
- Surrounded by low pressure
- Ridges are elongated highs
- Usually fair weather (stable air)
Low pressure system
- Less dense
- Air flow counter-clockwise, up and in
- Trough - elongated low pressure
- Usually bad weather (unstable air)
Temperature inversion
Temperature increases with altitude in layers.
Stable air below layer, unstable (turbulence) below layer.
- Frontal type- cool forced under warm (cold front) or warm spend over cold (warm front)
- Surface based
Low Clouds
- Surface to 6,500 AGL
- Small super cooled water droplets
- Rime Ice (-15 to -20)
Middle Clouds
- 6,500 - 20,000 AGL
- Large super cooled droplets
- Mixed Ice (-10 to -15)
High Clouds
- 20,000 - 60,000 AGL
- All ice crystals
- No ice formation
EVD Clouds
- Any altitude
2. Very unstable and turbulence
Fog formation
Fog is formed by adding moisture to the air and reducing the temperature to dew point.
Temperature / dew point
When temp and dew point are equal, a parcel of air can no longer hold water and visible moisture occurs.
Stable air
Cool dry air (Arctic)
V) poor C) stratus T) little to none I) rime ice P) steady P) high