Weather Information Flashcards
Name several types of fog. (AC 00‑6)
a. Radiation fog
b. Advection fog
c. Upslope fog
d. Frontal fog or precipitation-induced fog
e. Steam fog
Give some examples of the various NWS weather charts you will used during preflight planning. (AC 00‑45)
a. Surface analysis chart
b. Weather depiction chart
c. Short-range surface prognostic chart
d. Significant weather prognostic chart
e. Convective outlook chart
f. Constant pressure analysis chart
At what rate does atmospheric pressure decrease with an increase in altitude? (AC 00‑6)
1” Hg per 1,000 feet.
What are constant pressure analysis charts?
A chart with a plot of contours showing height above mean sea level of selected isobaric surfaces. It may contain analysis of height, wind, temperature, humidity, and other elements.
What valuable information can be determined from Winds and Temperatures Aloft Forecasts (FB)?
MATT
Most favorable altitude — based on winds and direction of flight.
Areas of possible icing — by noting air temperatures of +2°C to -20°C.
Temperature inversions.
Turbulence — by observing abrupt changes in wind direction and speed at different altitudes.
What is advection fog, and where is it most likely to form? (AC 00‑6)
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 geographic area, and at any time of the day or night
While enroute how can a pilot obtain updated weather information?
a. FSS on 122.2 and appropriate RCO (remote communication outlet) frequencies.
b. ATIS broadcasts along your route of flight.
c. HIWAS (Hazardous Inflight Weather Advisory Service).
d. Datalink weather—cockpit display of FIS-B information.
e. ATC (workload permitting).
What is a Convective SIGMET? (AC 00‑45)
Convective SIGMETs (WST) implies severe or greater turbulence, severe icing and low-level wind shear. The forecast is valid for up to 2 hours.
a. Severe thunderstorm due to:
- Surface winds greater than or equal to 50 knots.
- Hail at the surface greater than or equal to 3⁄4 inches in diameter.
- Tornadoes
b. Embedded thunderstorms
c. A line of thunderstorms
d. Thunderstorms producing greater than or equal to heavy precipitation that affects 40% or more of an area at least 3,000 square miles.
Can onboard datalink weather (FIS-B) be useful in navigating an aircraft safely around an area of thunderstorms? (AC 00-24; AIM 7-1-10)
FIS aviation weather products are not appropriate for tactical avoidance of severe weather such as negotiating a path through a weather hazard area.
What is a “ridge”? (AC 00‑6)
A ridge (also called a ridge line) is an elongated area of relatively high atmospheric pressure. Air moving out of a high or ridge depletes the quantity of air; therefore, these are areas of descending air. Descending air favors dissipation of cloudiness; hence the association of high pressure and good weather.
What are PIREPs (UA), and where are they usually found? (AC 00‑45)
A Pilot Report or PIREP is a report of the actual weather conditions as encountered by an aircraft in flight
There are two types of PIREPs:
routine or “UA,” and urgent or “UUA.”
What is a “flight information service” (FIS)? (FAA-H-8083-25)
The FAA FIS-B system provides pilots and flight crews of properly-equipped aircraft with a flightdeck display of aviation weather and aeronautical information.
Describe several types of weather observing
a. Manual Observations — with only a few exceptions, these reports are from airport locations staffed by FAA personnel
b. AWOS — Automated Weather Observing System; broadcast local, minute-by-minute weather data directly to the pilot.
c. ASOS/AWSS — Automated Surface Observing System/Automated Weather Sensor System: Both systems provide continuous minute-by-minute observations that generate METARs and other aviation weather information.
What’s the atmosphere composed of?
78% Nitrogen
21% Oxygen
1% trace gases
What action is recommended if you inadvertently encounter icing conditions? (FAA-H-8083-15)
The first course of action should be to leave the area of visible moisture. This might mean descending to an altitude below the cloud bases, climbing to an altitude above the cloud tops, or turning to a different course.
What are the general characteristics of the weather a pilot would encounter when operating near a cold front? A warm front? (FAA-H-8083-25) Show Answer
Cold Front—cumulus or cumulonimbus, heavy rain accompanied by lightning, thunder and/or hail; tornadoes possible; during passage, poor visibility, winds variable and gusting; temperature/dew point and barometric pressure drop rapidly.
Warm Front—stratiform clouds, drizzle, low ceilings and poor visibility; variable winds; rise in temperature.
Extra The weather associated with a front depends on the amount of moisture available, the degree of stability of the air that is forced upward, the slope of the front, the speed of frontal movement, and the upper wind flow.
Describe the basic elements of a METAR. (AC 00‑45)
A METAR report contains the following elements in order as presented:
a. Type of reports — the METAR, and the SPECI (aviation special weather report).
b. ICAO station identifier — 4-letter station identifiers; in the conterminous U.S., the 3-letter identifier is prefixed with K.
c. Date and time of report — a 6-digit date/time group appended with Z (UTC). First two digits are the date, then two for the hour, and two for minutes.
d. Modifier (as required) — if used, the modifier AUTO identifies the report as an automated weather report with no human intervention. If AUTO is shown in the body of the report, AO1 or AO2 will be encoded in the remarks section to indicate the type of precipitation sensor used at the station.
e. Wind — 5-digit group (6 digits if speed is over 99 knots); first three digits = wind direction, in tens of degrees referenced to true north. Directions less than 100 degrees are preceded with a zero; next two digits are the average speed in knots, measured or estimated (or, if over 99 knots, the next three digits).
f. Visibility — surface visibility in statute miles, space, fractions of statute miles (as needed), and the letters SM.
g. Runway visual range (RVR), as required.
h. Weather phenomena — broken into two categories: qualifiers, and weather phenomena.
i. Sky condition — amount/height/type (as required) or indefinite ceiling/height (vertical visibility). Heights are recorded in feet AGL.
j. Temperature/dew point group — 2-digit format in whole degrees Celsius, separated by a solidus (/). Temperatures below zero are prefixed with M.
k. Altimeter — 4-digit format representing tens, units, tenths, and hundredths of inches of mercury prefixed with A. The decimal point is not reported or stated.
l. Remarks (RMK), as required — operational significant weather phenomena, location of phenomena, beginning and ending times, direction of movement.
Example: METAR KLAX 140651Z AUTO 00000KT 1SM R35L/4500V6000FT -RA BR BKN030 10/10 A2990 RMK AO2
What is a METAR and what are the two types? (AC 00-45)
A METAR is an hourly surface observation of conditions observed at an airport.
1) Routine METAR report that is transmitted every hour and an aviation selected special weather report
2) 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.
Is frost considered to be hazardous to flight? Why? (AC 00‑6)
Yes, because the roughness of its surface spoils the smooth flow of air, thus causing a slowing of airflow. This resultins in a loss of lift.
What is an AIRMET (WA)? (AC 00‑45)
Advisories of significant weather phenomena that describe conditions at intensities that do not meet SIGMET criteria
intended for use by all pilots in the preflight and enroute phase of flight to enhance safety.
Explain the difference between a stable atmosphere and an unstable atmosphere. Why is the stability of the atmosphere important? (FAA-H-8083-25, AC 00-6)
Stable air means that the weather is likely to be calm. It may rain or snow slowly and steadily, it may be sunny, but the weather will not change quickly.
Unstable air means that the weather might change quickly with very little warning. Unstable air leads to sudden thunderstorms.
Why do surface winds generally flow across the isobars at an angle? (AC 00‑6)
Surface friction.
Name the three types of structural icing that may occur in flight. (AC 00-6)
Clear ice — the most dangerous type of structural ice not only because it is hard to see, but also because it can change the shape of the airfoil
Rime ice — f It is less dense, and usually easier to remove than clear ice. Rime ice tends to form wedge-shaped accretions that do not disturb airflow as much as clear ice.
Mixed ice — combination of clear ice and rime ice that has the worst characteristics of both, can form rapidly when ice particles become embedded in clear ice and build a very rough accumulation
Describe a mid-level significant weather (SIGWX) chart. (AC 00-45)
En route weather phenomena over a range of flight levels from 10,000 feet MSL to FL450, and associated surface weather features includes Icing, Turbulance
Describe the winds and temperature aloft forecasts (FB). (AC 00-45)
Forecast Winds and Temperatures Aloft is a forecast of wind direction and speeds and of temperatures at different altitudes for specific locations
What is a convective outlook chart? (AC 00‑45)
Convective outlooks are issued for the following eight days (issued separately for Day 1, Day 2, Day 3, and Days 4–8), and detail the risk of severe thunderstorms and tornadoes during the given forecast period,
Why is wind shear an operational concern to pilots? (AC 00‑6)
Wind shear is an operational concern because unexpected changes in wind speed and direction can be potentially very hazardous to aircraft operations at low altitudes on approach to and departing from airports.
What is the definition of the term freezing level and how can you determine where that level is? (AC 00-45)
The lowest altitude in the atmosphere over a given location at which the air temperature reaches 0°C.
Freezing level forecast
Area Forecast
PIREP’s
AIRMET’s
SIGMET’s
Surface Analysis Chart
Winds and Temps Aloft
Describe a U.S. low-level significant weather prog chart SigWx. (AC 00‑45)
for altitudes below 24,000 ft.
Depicts a “snapshot” of weather expected at the specified valid time. The charts depict weather flying categories, turbulence, and freezing levels, and are issued four times per day in two types: a 12-hour and a 24-hour prog.
What is HIWAS?
Hazardous Inflight Weather Advisory Service is a continuous broadcast of hazardous weather information which is transmitted over selected VORs
List the effects of stable and unstable air on clouds, turbulence, precipitation and visibility. (AC 00‑6)
See attachment
What information does a weather depiction chart provide? (AC 00‑45)
The weather depiction chart contains a plot of weather conditions at selected METAR stations and an analysis
The chart is issued eight times daily.
What is a surface analysis chart? (AC 00‑45)
The surface analysis chart is a computer-generated chart, with frontal and pressure analysis
Transmitted every 3 hours covering the contiguous 48 states and adjacent areas
State the general characteristics in regard to the flow of air around high and low pressure systems in the Northern Hemisphere. (AC 00‑6)
Low Pressure — inward, upward, and counterclockwise High Pressure — outward, downward, and clockwise
