Weather Information Flashcards
Most of the Earth’s weather occurs in what region of the atmosphere? (
Most of the Earth’s weather occurs in the troposphere, which begins at the Earth’s surface and extends up to approximately 36,000 feet. As the gases in this layer decrease with height, the air becomes thinner and the temperature decreas1/s from about 15°C (59°F) t6 -56.5°C (-70°F).
What are the standard temperature and pressure values for sea level?
15 C (59) 29.92 (1013.2)
What are “isobars”?
An isobar is a line on a weather chart that connects areas of equal or constant barometric pressure.
If the isobars are relatively close together on a surface weather chart or a constant pressure chart, what information will this provide?
The spacing of isobars on these charts defines how steep or shallow a pressure gradient is. When isobars are spaced very close together, a steep pressure gradient exists, which indicates higher wind speeds. A shallow pressure gradient (isobars not close together) usually means wind speeds will be lower.
What does “dew point” mean?
Dew point is the temperature to which a sample of air must be cooled to attain the state of saturation.
When temperature and dew point are close together (within 5°F}, what type of weather is likely?
~isible m~i~ture in the form of clouds, dew, or fog. These are also ideal cond1t1ons for carburetor icing.
What factor primarily determines the type and vertical extent of clouds?
The stability of the atmosphere.
Explain the difference between a stable atmosphere and an unstable atmosphere. Why is the stability of the atmosphere important?
The stability of the atmosphere depends on its ability to resist vertical motion. A stable atmosphere makes vertical movement difficult, and small vertical disturbances dampen out and disappear. In an unstable atmosphere, small vertical air movements tend to become larger, resulting in turbulent airflow and convective activity. Instability can lead to significant turbulence, extens’ive vertical clouds, and severe weather.
How can you determine the stability of the atmosphere?
When temperature decreases uniformly and rapidly as you climb (approaching 3GC per 1,000 feet), you have an indication of unstable air.
If the temperature remains unchanged or decreases only slightly with altitude, the air tends to be stable.
When air near the surface is warm and moist, suspect instability.
List the effects of stable and unstable air on clouds, turbulence, precipitation and visibility.
State the general characteristics in regard to the flow of air around high-pressure and low-pressure systems in the Northern Hemisphere. (AC 00-6)
Low Pressure- inward, upward, and counterclockwise
High Pressure-outward, downward, and clockwise
What is a “trough”? (AC 00-6)
elongated area of relatively low atmospheric pressure .
a low or trough is an area of rising air.
Rising air is conducive to cloudiness and precipitation this brings bad weather.
What is a “ridge”? (AC 00-6)
Elongated area of high atmospheric pressure.
Descending air.
Good weather.
What is the primary means of obtaining a weather
briefing? (AIM 7-1-2, 7-1-4)
FSS. toll-free number (1-800-WX BRIEF).
What are some examples of other sources of weather
information? (AIM 7-1-2, 7-1-7, 7-1-8)
a. Telephone Information Briefing Service (TIBS) (FSS)
b. private industry sources.
c. The Direct User Access Terminal System (DUATS) and Lockheed Martin Flight Services (DUATSII).
d. In Alaska, Transcribed Weather Broadcast (TWEB) locations and telephone access to the TWEB (TEL-TWEB).
If your route of flight takes you toward a low-pressure
system, in general what kind of weather can you expect?
What if you were flying toward a high-pressure system?
(AC 00-6)
A low-pressure system is characterized by rising air: cloudiness , precipitation and bad weather.
A high pressure no clouds and good weather.
Describe the different types of fronts. (
Cold front-occurs when a mass of cold, dense, and stable air advances and replaces a body of warmer air.
Occluded front- fast-moving cold front catches up with a slow-moving warm front.
Warm front-warm air mass contacts and flows over a colder air mass.
Stationary front: two air masses are relatively equal,
influences the local weather for days.
The weather is typically a mixture of both warm and cold fronts.
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)
Cold Front: towering cumulus or cumulonimbus, heavy rain with 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.
Does the weather data provided by commercial and/or third-party vendors satisfy the preflight action required by 14 CFR §91.103? (AIM 7-1-3)
No. They might not meet with the standards.
Only services provided by FAA, NWS or their contractor
(such as the DUATS and Lockheed Martin Flight Se rvices DUATS II )
What type of weather briefings are available from an FSS briefer? (AIM 7-1-4)
Standard Briefing - Request anytime you are planning a flight usally wihin 6 hours
Abbreviated Briefing - supplement previous briefing, or when you need only one or two items.
Outlook Briefing - Request whenever your proposed time of departure is six or more hours from the time of the briefing. This is for planning purposes only.
Inflight Briefing - Request when needed to update a preflight briefing.
What pertinent information should a weather briefing include? (AIM 7-1-4)
a. Adverse Conditions
b. VFR Flight Not Recommended
C. Synopsis
d. Current Conditions
e. Enroute Forecast
f. Destination Forecast
g. Winds Aloft
h. Notices to Airmen
1. ATC Delay
J. Pilots may obtain the following from FSS briefers upon request:
information on special use airspace (SUA) and SUA -related
airspace , including alert areas, MOAs , MTRs (IFR , VFR, VR,
and SR training routes), warning areas, and ATC assigned
airspace (ATCAA); a review of the printed NOT AM publication;
approximate density altitude data; information on air
traffic services and rules; customs/immigration procedures;
ADIZ rules; search and rescue; GPS RAIM availability for I
hour before to I hour after ETA or a time specified by the pilot;
and other assistance as required .
What is a Flight Information Services-Broadcast (FIS-B) ?
(FAA-H-8083-25)
a ground broadcast service provided through the Automatic Dependent
Surveillance-Broadcast (ADS-B)
Provides flight-deck display of aviation weather and aeronautical information
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)
No it is not real-time information
This data is typically updated every 5 minutes, but can be as much as 15 minutes old by the time it displays in the cockpit.
What is HIWAS? (AIM 7-1-9)
continuous broadcast of in flight weather advisories includes
Aviation Weather Warnings
SIGMETs
Convective SIGMETs,
AIRMETs, and urgent PIREPs.
