Weather Flashcards
What atmospheric factor causes rapid movement of surface fronts?
Upper winds blowing across the front
What weather difference is found on each side of a dry line?
Dew point difference, a dew point front or dry line is formed when two air masses of similar density and temperature meet
What term describes an elongated area of low pressure?
A trough is an elongated area of low flow pressure
Where is the normal location of the jet stream relative to surface lows and fronts?
The jet stream is normally located north of the surface systems
What type of icing is associated with the smallest size of water droplet similar to that found in low level stratus clouds?
Rime ice forms when drops are small such as those in level stratus clouds
What condition is necessary for the formations of structural icing in flight?
Flying thru visible moisture and the temperature where the water strikes the aircraft must be freezing
What condition is indicated when ice pellets are encountered during flight?
Freezing rain at higher levels
When will frost most likely form on aircraft surfaces?
When both the temperature and dew point are below freezing. Occurs on clear nights with little or no winds
What type of precipitation is an indication that super cooled water is present?
Freezing rain at flight level
Radiation fog occurs when there is a surface based temperature inversion, what characterizes a ground based inversion?
Poor visibility
What condition produces the most frequent type of ground or surface based temperature inversion?
Terrestrial radiation on a clear, calm night
What causes advection fog to form?
Warm moist air flowing over colder surfaces
What causes upslope fog to form?
Moist, stable air moving over higher ground, cooling adiabatically
What minimum thickness of cloud layer is indicated if precipitation is reported as light or greater intensity?
More than 4000ft thick
Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?
Rain begins to fall
What is and where do squall lines most often develop?
A narrow band of active thunderstorms, develops ahead of a cold front in moist unstable air