Weather Flashcards
What is a front?
boundary between to airmasses
What are the different types of fronts?
Cold, Warm, Occluded and Stationary
What can you expect crossing a front?
Change in wind direction
Describe a warm front
- Warm mass of air advancing to replace a body of colder air.
- Moves slowly (10 to 25 mph)
- Stratiform clouds and fog can be expected along the frontal boundary.
- Poor visibility
Describe a cold front
- Cold, dense mass of air advancing to replace a body of warmer air.
- Moves more rapidly than warm fronts (25 to 30mph)
- It stays close to the ground and acts like a snowplow, sliding under the warmer air and forcing the less dense air aloft.
- tower cumulus or cumulonimbus clouds, with heavy rain, lightning, thunder, and/or hail.
- Good visibility eventually prevails
Describe a Stationary front
- two air masses are relatively equal, the boundary or front that separates them remains stationary and infulences the local weather for days.
- Weather is a mix that can be found in both warm and cold fronts
Describe a Occluded front
- fast moving cold front catches up with a slow-moving warm front.
- As front approaches warm front weather prevails but is immediately followed by cold front.
What do you need for a thunderstorm to form
- Warm moist air
- Unstable atmosphere,
- Lifting action
What are the 3 stages of a thunderstorm
- Cumulus
- Mature
- Dissipating
How do you avoid a thunderstorm
- Fly at least 20 miles around the thunderstorms
- Stay out from under the anvil top to avoid hail
- Be careful of microburst
- if you fly into a thunderstorm, use radar or ask ATC to vector you around the heavy cells.
- Don’t set autopilot to hold altitude only attitude
- Turn up cockpit lighting for lightening flashes
- If on approach and you get sudden increase in indicated airspeed expect a decrease to follow.
What is wind shear and where are you most likely to encounter it?
- Windshear is a sudden, drastic change in windspeed and/or direction over a very small area.
- Windshear is associated with low-level temperature inversion, passing frontal systems, thhunderstorms.
Why/where is windshear most dangerous?
- During approach and landing.
- Due to the rapid shift in wind direction on takeoff and landing airspeed is slow and abrupt fluctuations in airspeed can induce a stall
What are some types of fog?
Advection, radiation, upslope, precipitation induced, steam and ice.
Radiation fog
- occurs on clear nights with relatively little to no wind present
- Ground cools rapidly due to terrestrial radiation and the surrounding air temperature reaches its dew point.
Advection fog
- warm, moist air moving over a cold surface.
- common in coastal areas
Upslope fog
- moist, stable air forced up sloping lad features like a mountain range.
Steam fog
- cold, dry air moves over warm water
- common over bodies of water during the coldest times of the year
- Low-level turbulence and icing are commonly associated with steam fog
Ice fog
- Occurs in cold weather when the temperature is much below freezing and water vapor forms directly into ice crystals
- Occurs in the arctic regions,
What condition must there be for structural icing to form?
Visible moisture and below freezing temperatures at the point it meets the aircraft surface.
TAF
Terminal Aerodrome Forecast
- updated every 6 hours
- Provides forecast information typically for a 24 hour period
- Covers an area approximately 5 miles from the center of an airport
METAR
- Meterological Aerodrome Report
- Updated hourly or as conditions change
FA
- Area Forecast
- issued 3 times a day
- Valid for 18 hours
- covers an area the size of several states
- used to verify airport condition at airports that do not have TAF’s
Prognostic Charts
- Used for determining the weather in the future
- Shows frontal boundaries
Winds Aloft
- Provide wind speed/direction/temperature for a given altitude at every 3000 foot interval.
Radar
- Provides location, intensity and direction of cell movement.
