Up to what altitude does the GFA cover?
24000ft
How many forecast areas are there in Canada
7
What is the marginal VFR criteria
Visibilities between 3 and 5 miles and cloud heights between 1000 and 3000ft
The OCNL and PTCHY descriptors indicate what percent chance of occuring
26-50%
A correction to the GFA is issued for which events (3)
- An occurence of unforecast weather that does not require an Airmet
- Forecast phenomena fail to occur
- A significant error was made.
Sigmets advisories include the following significant weather:
- Active thunderstorm areas
- hurricanes/tropical storms
- Moderate hail
- Severe turbulence
- severe icing
- Marked mountain waves
- sandstorms/duststorms
- volcanic ash
- severe squall lines
- LLWS
- Tornadoes
what are the 3 sigmet headers?
WS, WV, WC
When is the numbering of a sigmet reset?
0000z
what are the sigmet validity and lead times
WS - valid 4 hrs and 4 hr lead time
WV,WC- 12 hour lead time and valid for 6 hrs
What are the maximum recommending coordinate points for the 3 shapes of sigmet?
circle - 1
line - 4
polygon - 7
An Airmet will be issued for which following phenomena (6)
- SFC WND SPD widespread above 30kts
- MVFR conditions over a widespread area
- TCU and CB
- MDT turb
- MDT icing
- MDT mountain waves
What are the criteria for an urgent pirep (7)
- Volcanic Ash
- Tornado
- SEV turb
- SEV icing
- Hail
- LLWS
- any other hazardous phenomena
Why would the 3000ft forecast winds be omitted from an FB?
If the station elevation is greater than 1500ft
What are the limitations of aviation forecasting? (6)
- Human interpretation
- Numerical weather prediction
- Extrapolation
- Scientific knowledge
- Experience
- Forecast products
Upper charts are produced for which times?
0000z and 1200z
What is the difference between the 2 850 charts?
one has fronts the other doesn’t
How soon are the upper charts transmitted?
1.5 hours after obs time
What are the contour intervals spaced at?
6 decameters
Contour lines represent?
lines of equal height
