Weather Flashcards
What is the primary means of obtaining a weather briefing?
The primary source of preflight weather briefings is a briefing from a briefer at the AFSS/FSS. These briefings are available through 1-800-WX-BRIEF.
What are some examples of other sources of weather information?
Weather and aeronautical information from numerous private industry sources.
FSS
Where can you find a listing of FSS and weather information numbers?
In the AFD under “FAA and NWS telephone number” section.
What type of weather briefings are available from an FSS briefer?
a. Standard Briefing
b. Abbreviated Briefing - when you need an update to a previous briefing or only one or two items.
c. Outlook Briefing - When your proposed time of departure is six or more hours from the time of the briefing.
d. Inflight Briefing - request when needed to update a preflight briefing.
What pertinent information should a weather briefing include?
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
i. ATC Delays
j. Airspace conditions (TFR’s)
What is an ATIS?
Automated Terminal Information Service - a continuous broadcast of recorded non control information in selected high activity terminal areas. Its purpose is to improve controller effectiveness by automating the transmission of routine information.
What type of information is provided in an ATIS broadcast?
a. Time of the latest observation
b. Wind (direction & speed)
c. Visibility (distance sm)
d. Cloud Layers & Ceiling (AGL)
e. Temperature and Dewpoint
f. Altimeter
g. Instrument approach & runway in use
What is a METAR?
A routine weather observation of the conditions at a given site and time.
What information is contained in a METAR?
a. ICAO station identifier
b. date and time of report
c. wind (direction and speed)
d. visibility
e. weather phenomena
f. sky condition
g. temperature/dew point
h. altimeter
i. remarks
Describe the various types os weather observing programs now in use.
a. Manual observations - made by FAA or NWS personnel.
b. AWOS - automated weather observing system
c. ASOS/AWSS - automated surface observing system. Can be transmitted over VHF radio or the voice portion of a NAVAID.
What are PIREPs
These reports contain information concerning weather as observed by pilots in route. Required elements for all PIREPs are message type, Location, time, flight level, type of aircraft, and at least one weather element encountered.
What are terminal aerodrome forecasts?
A TAF is a concise statement of the expected meteorological conditions within a five statue mile radius from the center of an airport runway complex during a 24 hour.
What is an aviation area forecast (FA)?
Discontinued Product - Use GFA now
GFA is Graphical Forecast
- What is a convective SIGMET?
2. Conditions for convective SIGMET to be issued
- Convective SIGMET implies severe or greater turbulence, severe icing and low-level wind shear.
- a. severe thunderstorms due to: surface winds greater than or equal to 50 kn, hail at the surface greater to 3/4 inches in diameter, tornadoes
b. embedded thunderstorms
c. A line of thunderstorms
d. thunderstorms that produce precipitation levels greater than or equal to heavy intensity precipitation, affecting 40% or more of an area at least 3000 mi.²
- What is a SIGMET?
2. What conditions would require a SIGMET to be issued?
- Advises of non-convective weather that is potentially hazardous to all aircraft. Segments are issued for the 6 areas corresponding to the FA areas. The maximum forecast is four hours.
- a. severe icing not associated with a thunderstorm
b. severe or extreme turbulence or a clear air turbulence not associated with thunderstorms
c. Dust storms or sandstorms lowering surface or in-flight visibility’s to below 3 miles
d. Volcanic ash
- What is an AIRMET?
- What conditions would require an AIRMET to be issued?
- What are the different types of AIRMETs?
- An AIRMET is an advisory of significant weather phenomenon for conditions at intensities lower than required for issuance of SIGMETs, issued every six hours.
- IFR, Extensive mountain obscuration, turbulence, strong surface winds, icing, and freezing levels
- Sierra describes IFR conditions and/or extensive mountain obscuration
Tango describes moderate turbulence, surface winds of 30 knots or greater, and/or non-convective low-level windshear
Zulu describes moderate icing and provides freezing level Heights
What valuable information can be determined from a Winds and Temperature Aloft Forecast?
How often is the Winds and Temperatures aloft forecast issued (FB)?
Most favorable altitude, areas of possible icing, Temperature inversions, turbulence
Winds and temperatures aloft are forecast 4 times daily.
What is a center weather advisory (CWA)?
An aviation warning for use by aircrews to anticipate and avoid adverse weather conditions In the en route and terminal environments. Valid for two hours
What is a convective outlook (AC)?
Convective Outlook is a flight planning tool used to avoid thunderstorm areas.
Describes the prospects for general thunderstorm activity during the following 24 hour periods
What is a surface analysis chart?
chart that shows pressure systems and fronts
overview of winds, temperatures and dewpoint temperatures at chart time
What is a radar summary chart?
Displays areas of precipitation as well as information about type, intensity, configuration, coverage, echo top, and cell movement of precipitation.
What is a winds and temperatures aloft chart?
Winds and Temperature Aloft time period
A computer generated chart showing bot observed and forecast winds and temperatures aloft from 6,000 to 39,000 feet MSL.
12 hour prognostic charts valid at 1200Z and 0000Z
What are significant weather prognostic charts?
chart that shows forecast of weather conditions
shows fronts, precipitation, pressure systems, low ceilings
issued 4x/day and valid for 12, 24, 36 and 48 hours
What altitude range does a low-level significant weather prog chart cover?
Surface to 24,000 feet which is 400mbs
What is a convective outlook chart?
This chart shows areas forecast to have the potential for any convection, and/or extreme weather events such as tornados, wind gusts 50 knots or greater, or hail 3/4 inch diameter or greater for the next three days.
What are NOTAMs ?
Notices to Airmen. Time critical information which is not printed on any aeronautical chart.
What type of information might a NOTAM contain?
Airport or runway closures, changes in the status of navigational aids, ILS’s, radar service or other essential information for planning a flight.
What are the four basic groups of NOTAMs?
a. (D) NOTAMs - pertain to en route nav aids, civil public use airports listed in the AFD, facilities, services, and procedures
b. FDC NOTAMs - regulatory information such as, changes in IFR charts, procedures, and airspace usage
c. POINTER NOTAMs - issued by a FSS to highlight or point out another NOTAM.
d. MILITARY NOTAMs - pertain to military nav aids and airports
Where can NOTAMs be obtained?
a. flight service station
b. authorized third party site.
c. FAA’s NOTAM website
What are the two major classifications of thunderstorms?
a. Air mass thunderstorm
c. Steady state thunderstorm
What is an air mass thunderstorm?
a. Results from surface heating
b. Only lasts an hour or two
c. Occur in random unstable air
What is a steady-state thunderstorm?
a. Usually forms in lines
b. Lasts for several hours
c. Produces heavy rain, winds, and possibly tornados
d. Normally associated with weather systems
Give some examples of charts and reports useful in determining the potential for and location of thunderstorms along your route.
a. Convective outlook
b. Radar summary chart
c. PIREPs
What are microbursts?
Small-scale intense downdrafts which, on reaching the surface, spread outward in all directions. They cause both horizontal and vertical wind shears which can be hazardous to all aircraft.
Where are microbursts most likely to occur?
Almost anywhere there is convective activity.
What are some basic characteristics of a microburst?
Size: less than 1 mile in diameter as it descends from the cloud base. Can extend to 2.5 miles near ground level.
Intensity: downdrafts as strong as 6,000 ft. per minute. Horizontal winds near the surface as strong as 45 kts.
Duration: Seldom longer than 15 mins.
How can microburst encounters be avoided?
Check weather forecasts, such as TAFs and SIGMETs, for convective activity and reports, such as METARs and PIREPs, for wind shear and sudden airspeed changes in the airport area.
Define wind shear.
The rate of change of wind velocity per unit of distance. Can be vertical or horizontal.
State the areas where wind shear is most likely to occur.
a. Low-level temperature inversion
b. In a frontal zone or thunder storm
c. Clear air turbulence at high levels associated with a jet stream or strong circulation.
Why is wind shear an operational concern to pilots?
Unexpected changes in wind speed and direction can be potentially hazardous to aircraft operations at low altitudes on approach to and departing the airport. The sudden change in wind direction can cause a drastic loss of altitude.
What airplane characteristics will be observed in a wind shear with a sudden increase in headwind?
Increase in airspeed and altitude along with a nose-up pitching tendency.
What airplane characteristics will be observed in a wind shear with a sudden decrease in headwind?
Decrease in airspeed, altitude and pitch attitude.
What is the proper action from the pilot when wind shear is encountered?
For either an increase or decrease in headwind, the pilot should add power and increase pitch attitude to maintain proper airflow over the wings.
Concerning wind shear detections, what does LLWAS indicate?
Low-Level Wind Shear Alert System. It uses sensors located around an airport to compare wind direction and speed to detect a wind shear.
Where does most weather occur?
Troposphere which can extend to 36,000 feet
dewpoint defined
temperature to which a sample of air must be cooled to attain saturation
small temp/dewpoint spread means…
clouds, dew and fog is likely
Stable atmosphere has (4 qualities)
stratiform clouds
smooth air
steady precipitation
fair to poor visibility
Unstable atmosphere has (4 qualities)
cumuliform clouds
rough air/turbulence
showery
good visibility
Low-Pressure systems - winds move
inward, upward and counterclockwise
High-Pressure systems - winds move
outward, downward and clockwise
Occluded front
Fast-moving cold front catches a slow-moving warm front
Trough described
extended line of low pressure
area of rising air - conducive to cloudiness and precipitation
low = bad weather
Ridge described
extended high-pressure area
good weather
Cold front weather passage has…
as front passes - cumulus or cumulonimbus clouds
heavy rain, lightning, thunder, gusty winds, rapid temperature drop
Warm front weather passage has…
stratiform clouds, drizzle, poor visibility and rise in temperatures
Weather with a front depends on
moisture content stability of the air that is forced upward slope of front speed of front upper wind flow
HIWAS transmissions include
Discontinued
TAF defined
TAFs issued
concise expected weather conditions within 5SM of center of airport
4 times per day
Possible icing area temperature range
+2C to -20C
CWA is defined as a
CWA is valid for…
short-term now-cast of hazardous weather
valid for 2 hours
Convective Outlook is
narrative/graphics for following 8 days for convection (severe and non-severe)
Convective Outlook probabilities shown as
MRGL SLGT ENH MDT HIGH
NOTAMs can be found in
NTAP
FAA Website
What altitude does a high-level Significant Weather Prognostic chart shows?
24,000 to 60,000 MSL
VFR conditions
> 3000 feet ceiling
+5 miles visibility
MVFR conditions
1000 to 3000 feet ceiling
3-5 miles visibility
IFR conditions
less than 1000 feet ceiling
1-3 miles visibility
Windshear can be found
around thunderstorms or convection
low-level temperature inversion
Clear Air turbulence with Jet Stream
frontal zone
3 stages of a Thunderstorm
Cumulus
Mature
Dissipating
What may be omitted from ATIS?
Ceiling and Sky if ceiling is above 5000 feet
What important risk factor is not shown by radar?
fog and clouds
If windshear increases your headwind what happens and what action do you take?
Causes an increase in airspeed, altitude and pitch
Action is to increase airspeed and pitch
If windshear decreases your headwind what happens and what action do you take?
Causes a decrease in airspeed, altitude and pitch
Action is to increase airspeed and pitch
How to avoid turbulence around thunderstorms
DO NOT
- fly under anvil
- fly under a T-Storm
- fly without airborne radar into clouds with embedded T-storms
- assume ATC can help
- use ADS-B wx for tactical maneuvering around T-storm
How to avoid thunderstorms if you do not have onboard T-storm detection
- Nexrad, but that may be 15-20 minutes old
- ask ATC for radar navigation and deviation
- listen to ATC for aircraft deviating
- monitor PIREPs
- avoid areas with 6/10 T-storm coverage
- avoid areas with vivid and frequent lightning
Risks of relying on ATC for in-flight assistance avoiding Thunderstorms
ATC radar limitations
frequency congestion
separation of traffic is their primary concern
Fying towards low-pressure system expect…
rising air
cloudiness
precipitation
bad weather
Determine stability of atmosphere by
temp decreases 3C/1000ft
if air near surface is warm and moist, suspect instability
vertical extent of clouds determined by
stability of atmosphere
Carb icing is likely
with visible moisture
temp/dew point close
Ceiling defined
lowest broken or overcast layer
5/8 sky coverage or more
Multi-cell Thunderstorms described
cluster of cells at different stages of their life-cycle
new cell takes place of one that moved downwind
Supercell described
single quasi-steady cell
rotating updraft for extended period
updraft up to 100knots / 9000 FPM
PIREPs available from
ATC
FSS
Aviationweather.gov
EFBs
FIS-B frequency
978
has Weather and aeronautical information
How to get weather while enroute
FSS on 122.2 ATIS ADS-B in ATC
Airmet Zulu
moderate icing
freezing level heights
(last thing you will see if you mess it up - icing)
Airmet Tango
Turbulence - moderate
windshear
surface winds - 30+ knots
