Obtaining Weather Information Flashcards
What is the primary means of obtaining a weather briefing?
individual briefing obtained from a briefer at the AFSS/FSS
What are primary sources of weather information?
- Telephone information briefing service (TIBS, AFSS)
- Aviation Weather Center
- Private weather providers
- 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
What is 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. Depicted on VORs with an “H” in upper right corner of identification box.
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), aircraft type, and at least one weather element encountered. 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 or 30 hour time period. Updated 4 times daily on the 6th hour (0000, 0600, 1200, 1800)
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 encompassing several states. Issued 3 times a day by the AWC for each of the 6 areas of the contiguous 48 states. Valid for 18 hrs
What information is provided in an aviation area forecast?
cover airspace between surface and 45,000 MSL
- Synopsis: weather affecting the FA area during the 18 hour valid period
- Clouds and weather: description of the clouds and weather for the first 12 hour period for each state or group, includes
- Ceiling (SCT, BKN, OVC) for clouds with bases higher than or equal to 1,000 feet AGL and below FL 180
- Cloud bases and tops (MSL)
- Precipitation
- Visibility between 3 and 6 SM and obstructions to vis
- Sustainted surface winds = or > 20kt
- 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 SIGMET?
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 and valid for 2 hours. If no hazardous weather exists, it’s still issued but states “CONVECTIVE SIGMET…NONE.”
a. severe thunderstorm due to:
* surface winds greater than or = 50 kt
* hail 3/4 inches or more 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 4 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?
- Issued every 6 hours w/ intermediate updates as needed
- Of interest to all aircraft, but directed more towards light aircraft/GA
- Moderate icing
- Moderate turbulence
- Sustained surface winds 30 kts or more
- widespread ceilings less than 1000 feet
- visibility less than 3 miles
- extensive mountain obscurement
Types of AIRMETs?
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 an 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 conditions in the en route and terminal environments. This is not 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. Issued every 3 hrs, shows:
- Sky cover
- Sea-level pressure
- pressure change
- dew point
- present weather
- temp
- wind
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, issued every 3 hrs beginning 0100Z. Provides total sky cover, cloud height, weather, obstructions to vis. Designed to be used for flight planning by giving an overall picture of Wx across the US.
Define LIFR.
low IFR - ceiling less than 500 feet and/or visibility less than 1 mile
