Aviation Weather Forecasts

Question 1

What is the GFA?

Answer 1

Graphical Area Forcast

Question 2

What is a TAF?

Answer 2

A forcast given for a specific aerodrom in a 5NM radius.
Typically issued 4 times a day for either 12, 24, or 30 hour period

Question 3

When is a TAF valid from?

Answer 3

The moment it is issued, even if periods of validity are given in the TAF itself

Question 4

In the FDs what does a 9900 code mean?

Answer 4

Light and variable winds (less than 5kts)

Question 5

If the elevation of your aerodrome is above 1500 ft, what will not show on the FDs?

Answer 5

The forcasted winds at 3000ft ASL will not show

Question 6

Are FDs given in AGL or ASL?

Answer 6

ASL

Question 7

If the wind direction number (the first two numbers) in an FD are between 51 and 86, what does this mean and how do you decode them?

Answer 7

It means the wind speed is higher than 100kts

• Subtract 50 from the wind direction
• Add 100 to the wind speed numbers

Example: The STL forcast for 39 000 is 731960.

73-50=23
19+100=119

So, the winds are 230@119kts and the temperature is -60o C.

Question 8

What is an AIRMET?

Answer 8

They’re used to amend a GFA. AIRMETS required a cancelling AIRMET (even if there is an end time in the AIRMET itself)

Question 9

What is a SIGMET?

Answer 9

An amendment to a GFA for significant/dangerous/violent changes in weather

Question 10

When is wind shear included in the TAF?

Answer 10

When it is 1500 AGL or below

Question 11

When is TEMPO used in a TAF?

Answer 11

When the change is expected to last less than one hour and, if its expected to recur, the total period of the change will not be more than half the total forcast period