Weather Flashcards
(26 cards)
What is a Convective SIGMET?
Tornadoes, lines of thunderstorms, hail greater than 3/4”, and/or wind gusts to 50kts or greater.
Valid for 2 hours.
What is a SIGMET?
Significant meteorological information.
Severe icing, severe or extreme turbulence, clear air turbulence, dust storms, sandstorms lowering visibility to less than 3 miles and volcanic ash.
Valid for 4 hours; 6 hours for hurricanes
Name several types of fog.
Radiation fog Advection fog Upslope fog Precipitation-induced fog Ice fog
What causes radiation fog to form?
The ground cools the adjacent air to the dew point on calm, clear nights.
What is advection fog, and where is it most likely to form?
Advection fog results from the transport of warm humid air over a cold surface. A pilot can expect advection fog to form primarily along coastal areas during the winter. Unlike radiation fog, it may occur with winds, cloudy skies, over a wide geographical area and at any time of the day or night.
What is upslope fog?
Upslope fog forms as a result of moist, stable air being cooled adiabatically as it moves up sloping terrain. Once the upslope wind ceases, the fog dissipates. Upslope fog is often quite dense and extends to high altitudes.
What is wind shear?
A sudden drastic shift in wind speed and/or direction.
Where is wind shear likely to occur?
It may occur at any level in the atmosphere but three areas are of special concern:
a. Wind shear with a low-level temperature inversion
b. Wind shear in a frontal zone or thunderstorm
c. Clear air turbulence (CAT) at high levels associated with a jet stream or strong circulation.
What is HIWAS?
Hazardous In-flight Weather Advisory Service is a continuous broadcast of in-flight weather advisories including summarized Aviation Weather Warnings, SIGMET’s, Convective SIGMET’s, Center Weather Advisories, AIRMET’s, and urgent PIREP’s.
What is a “flight information service” (FIS)?
FIS is a method of receiving aviation weather and other operational data in the cockpit that augments traditional pilot voice communication with FSS or ATC facilities. It is not intended to replace traditional pilot and controller/FSS preflight briefings or inflight voice communications.
What is a METAR?
A METAR is an hourly surface observation of conditions observed at an airport.
What are the two types of METAR’s?
- A routine METAR report that is transmitted every hour
- An aviation selected special weather report (SPECI). This is a special report that can be given at any time to update the METAR for rapidly changing weather conditions, aircraft mishaps, or other critical information.
What are TAF’s?
A Terminal Aerodrome Forecast is a concise statement of the expected meteorological conditions significant to aviation for a specified time period within five statute miles of the center of the airport’s runway complex (terminal).
What are the three stages of a thunderstorm?
Cumulus stage - updrafts cause raindrops to increase in size
Mature Stage - rain at Earth’s surface; it falls through or beside the updrafts; lightning; roll clouds
Dissipating Stage - downdrafts and rain begins to dissipate
Name the three types of structural icing that may occur in flight.
Clear ice
Rime ice
Mixed ice
What are isobars?
An isobar is a line on a weather chart which connects areas of equal or constant barometric pressure.
State the general characteristics in regard to the flow of air around high and low pressure systems in the Northern Hemisphere.
Low Pressure - inward, upward, and counterclockwise
High Pressure - outward, downward, and clockwise
What is an AIRMET?
An airman’s meteorological information.
Issued every 6 hours with amendments as necessary for weather phenomenon.
What are the types of AIRMET’s?
Sierra - IFR and mountain obscurations
Tango - Turbulence
Zulu - Ice
What is a microburst?
A downburst, concentrated, severe downdraft that induces an outward burst of damaging winds at the ground with a horizontal dimension of 2.2nm or less.
Any precipitation induced downdraft that produces critical wind shear conditions.
What 3 things are required to form thunderstorms?
- Lifting action
- Unstable air
- Moisture
What are the weather minimums for each airspace?
Class - Visibility | Clouds
Class A - n/a | n/a
Class B - 3 mi | clear of clouds
Class C - 3 mi | 500ft below, 1000ft above, 2000ft horizontal
Class D - 3 mi | 500ft below, 1000ft above, 2000ft horizontal
Class E - 3 mi | 500ft below, 1000ft above, 2000ft horizontal
Class G - 1 mi | clear of clouds
What is LIFR?
Low IFR - ceiling less than 500 feet and/or visibility less than 1 mile.
What is IFR?
Ceiling 500 to less than 1,000 feet and/or visibility 1 to less than 3 miles.
