Obtaining Weather Information Flashcards
What is the primary means of obtaining a weather briefing?
individual briefing obtained from a briefer at the AFSS/FSS
Sources of weather information?
a - Telephone information briefing service (TIBS, AFSS)
b - Weather and aeronautical information from numerous private industry sources
C- DUATS
d- TWEB (alaska)
What pertinent information should a weather briefing include?
- adverse conditions
- VFR flight not recommend
- synopsis
- Current conditions
- Enroute forecast
- Destination forecast
- Winds aloft
- NOTAMs
- ATC delay
EFAS?
Enroute Flight Advisory Service
Specifically designed to provide enroute aircraft with timely and meaningful weather advisories pertinent to type of flight, route, altitude. EFAS is also a central collection and distribution point for PIREPS. Communication available between 5,000 and 17,500 MSL on 122.0. Known as “flight watch”
What is HIWAS?
Hazardous In flight Weather Advisory Service -
continuous broadcast of in flight weather advisories including Aviation Weather Warnings, SIGMETs, Convective SIGMETs, Center weather advisories, AIRMETs, and urgent PIREPs.
What is a METAR?
Aviation routine weather report is an observer’s interpretation of the weather conditions at a given site and time.
Elements of a METAR?
a. Type - routine and SPECI
b. Station identifier
C. Date and time
d. Modifier
e. Wind
f. Visibility
g. Runway Visual Range
h. Weather phenomena
i. Sky condition
j. Temperature/dew point group
k. altimeter
PIREP elements and info?
Required elements - type of report, location, time, flight level (in MSL), aircrft type, and at least one weather element encountered. Distance and vis in SM; all other distances in NM. UTC time. Routine (UA) and Urgent (UUA)
What are TAFs?
Terminal aerodrome forecasts
Concise statement of the expected meteorological conditions within a 5 SM radius from the center of an airport’s runway complex during a 24 hour time period.
Elements of TAF?
a. type - routine TAF, or amended TAF AMD
b. ICAO ident.
c. Date and time
d. valid period date and time
e. forecasts - wind vis, sig weather, sky condition, non convective low level wind shear, change indicators, probibility
What is an aviation area forecast
A forecast of visual meteorological conditions (VMC), clouds, and general weather conditions over an area the sie of several states. Must be used along with inflight weather advisories to determine forecast enroute weather and to interpolate conditions at airports where no TAFs are issued, i order to understand the complete weather picture. FAs are issued 3 times a day by the AWC for each of the 6 areas of the contiguous 48 states.
What information is provided in an aviation area forecast?
Area forecasts = FA cover airspace between surface and 45,000 AMSL
a. synopsis: weather affecting the FA area during the 18 hour valid period
b. Clouds and weather: description of the clouds and weather for the first 12 hour period for each state or group, includes -
- –Cloud amount (SCT, BKN, OVC) for clouds with bases higher than or equal to 1,000 feet AGL and below FL 180
- –Cloud bases and tops (AMSL)
- – Precipitation
- – Visibility between 3 and 6 SM and obstructions to vis
- – sustainted surface winds = or > 20kt
c. 12 to 18 hour categorical outlook: IFR, MVFR, VFR, including expected precip and or obstructions to vis
What are WST, WS, WA?
Inflight aviation weather advisories. Forecasts that advise enroute aircraft of development of potentially hazardous weather. All heights are in MSL, except CIG which are AGL
WST - convective SIGMET
WS - SIGMET
WA - AIRMET
What is a convective SIGMENT?
A convective SIGMET (WST) implies severe or greater turbulence, severe icing and low level wind shear. It may be issued for any convective situation which the forecaster feels is hazardous to all categories of aircraft. Issued hourly at H +55.
a. severe thunderstorm due to: surface winds greater than or = 50 kt
- – hair greater or = 3/4 inches in diameter
- – tornados
b. embedded thunderstorms
c. line of thunderstorms
d. thunderstorms producing greater than or equal to heavy precip that affects 40 percent or more of an area at least 3,000 square miles
What is a SIGMET?
WS advises of non convective weather that is potentially hazardous to all aircraft. WS are issued for the six areas corresponding to the FA areas. The maximum forecast period is four hours. In the US, SIGMETs are issued when the following phenomena occur or are expected:
a. severe icing not associated with a thunderstorm
b. severe or extreme turbulence or clear air turbulence (CAT) not associated with thunderstorms
c. dust storms or sandstorms lowering surface or in flight visibilities to below 3 miles.
d. volcanic ash
What is an AIRMET?
WA are advisories of significant weather phenomena that describe conditions at intensities lower than those which require issuance of SIGMETS, intended by use of all pilots int he preflight and enroute phase of flight to enhance safety. WA bulletins are issued every 6 hours Includes outlook for conditions expected after the AIRMET valid period and contain details about IFR, extensive mountain obscuration, turbulence, strong surface winds, icing, and freezing levels.
Types of AIRMETs?
Sierra, Tango, and Zulu
Sierra - IFR conditions and or extensive mountain obscuration
Tango - moderate turbulence, sustained surface winds of 30 knots or >, and or nonconvective low level wind shear
Zulu - moderate icing and provides freezing level heights
What is a winds and temperature aloft forecast?
FB are computer based forecasts of wind direction, speed, and temperature at specified times, altitudes, and locations. Produced 4 times daily. no amendments issued. Not issued for altitudes within 1,500 feet of a location’s elevation.
What valuable information can be determined from a FB?
Most favorable altitude
Areas of possible icing
Temperature inversions
Turbulence - by observing abrupt changes in wind direction and speed at different altitudes
What is a CWA
A Center Weather Advisory. Warning for use by aircrews to anticipate and avoid adverse weather condtiions in the en route and terminal environments. This inot a flight planning product. Reflects current conditions expected at the time of issuance, and or is a short range forecast for conditions expected to begin within 2 hours from that time. Only valid for maximum of 2 hours.
What are some available weather charts?
Surface analysis chart weather depiction chart Radar summary schart Sig weather prog chart short range surface prog chart convective outlook chart constant pressure analysis chart
What is a surface analysis chart?
The chart provides a ready means of locating pressure systems and fronts. It also gives an overview of winds, temperatures, and dew point temperatures at chart time.
What information does a weather depiction chart provide?
Gives a broad overview of the observed flying category conditions at the valid time of the chart. Provides total sky cover, cloud height, weather, obsturctions to vis, vis.
LIFR?
low IFR - ceiling less than 500 feet and or vis less than 1 mile
IFR
Ceiling 500 to less 999 feet and or visibility 1 to less than 3 miles
MVFR
Marginal VFR - ceiling 1,000 to 3,000 feet and or vis 3 to 5 miles inclusive
VFR
Ceiling greater than 3,000 feet and vis greather than 5 miles. Includes sky clear
What are radar summary charts?
A graphical display of areas of precip as well as info about type, intensity, configuration, converage, echo top, and cell movement of precip. Severe weather watches are also plotted if they are in effect when the chart is valid.
They are useful for identifying general areas and movement of precip and or thunderstorms. Does NOT DISPLAY clouds and fog.
What are short range surface prognostic charts?
Provide a forecast of surface pressure systems, fronts, and precipitation for a 2 day period.
Used to obtain an overview of the progression of surface weather features during the next 48 hours.
Describe a US low level significant weather prog chart.
Page 1-40 - REVIEW next to chart
Describe a Mid Level Sig weather chart.
SIGWX provides forecast and an overview of significant enroute weather over a range of flight levels from 10,000 feet MSL to FL450 and associated surface weather features. It is a snapshot of weather expected at the specified valid time and depicts numerous weather elements that can be hazardous to aviation.
What information ca be obtained from the US High Level Sig Weather Prog Charts
Weather conditions above 24,000 feet.
- Jet streams
- cumulonimbus clouds
- turbulence
- tropopause heights
- surface fronts
- Tropical storm complexes and cyclones
- squall lines
- volcanic eruption sites
- sandstorms and duststorms
What is a convective outlook chart?
Depicts areas forecast to have potential for severe (tornado, 50kt+, hail .75in) and non severe (general) convectionand specific severe weather threats during the following three days. The charts defines areas of slight risk, moderate, and high of severe thunderstorms for a 24 hours period.
What are constant pressure analysis charts?
A constant pressure analysis chart is an upper air weather map where all information depicted is at the specified pressure of the chart.
What is a constant pressure surface?
Any surface of equal pressure in the atmosphere
What can a pilot use a constant pressure analysis chart for?
Approx. air temp, wind, temp dewpoint spread. Also can determine highs, lows, troughs, ridges aloft by the heigh contour patterns resembling isobars on a surface map
What do closely spaced contours mean on a constant pressure chart?
Strong winds just as closely spaced isobars
What significants do isotherms have on constant pressure chart?
Depicted as dashed lines. Drawn in 5 centigrade intervals
Show horizontal temperature variations at chart altitude. By examining, can determine if your flight will be toward colder or warmer air.
Subfreezing temperatures and a temperature dewpoint spread of 5 centigrade of less susgesst possible icing.
What is the significance of the isotach lines on a constant pressure chart?
Lines of constant wind speed analyzed on the 300 and 200 mb charts. They separate higher wind speeds from lower wind speeds and are used to map wind speed variations over a surface. They are drawn in 20 knots intervals and begin at 10 knots. They identify the magnitude of wind speed variations.
Strong gradients are closely spaced isotachs and identify large wind speed variations. Zones of very strong winds are highlighted by hatches.
