TAF

Question 1

What is a TAF?

Answer 1

A concise statement of the expected meteorological conditions at an airport during a specified period
(usually 24 hours).

Question 2

What times are TAF’s released?

Answer 2

3 Times a day; 07Z, 15Z, 23Z.

Question 3

What is a From line?

Answer 3

They are an indicator of a change period in the forecast. Once the From Line becomes valid, all other conditions preceding this group are superseded by the conditions indicated in this group.

Question 4

How many hours does a Becoming/Tempo line last and why?

Answer 4

Becoming, 2 Hours - any less than one hour otherwise a FM line should be used. Tempo 6 Hours - These temporary conditions are expected to last less than one hour in each instance and overall cover less than half of the period indicated by the time.

Question 5

What goes into a From line?

Answer 5

This forecast line shall contain all elements (wind, visibility, weather, sky, minimum altimeter, and any other conditional groups) of a predominate forecast line.

Question 6

What goes into a Becoming line?

Answer 6

All groups for which a change is forecasted; a group omitted from this change line would indicate that the group from the previous predominate line remains valid.

Question 7

What goes into a Tempo line?

Answer 7

All groups for which a change is forecasted; a group omitted from this change line would indicate that the group from the previous predominate line remains valid.

Question 8

What lines report changes in QNH?

Answer 8

FM and BECMG

Question 9

What does not go in a tempo line?

Answer 9

Minimum altimeter, significant weather in the vicinity, non-convective low-level wind shear, icing
or turbulence.

Question 10

How is icing/turbulence encoded?

Answer 10

NOT associated with a thunderstorm.
6(Ic)hihihi(tL)
Type, Base, Thickness (9 thousand max)
5(B)hbhbhb(tL)
Type, Base, Thickness (9 thousand max)

Question 11

How is non-convective wind shear reported?

Answer 11

Wind shear is defined as a rapid change in horizontal or vertical wind speed and/or direction, over a short distance. It is used only to forecast wind shear not associated with convective activity from the surface to 2,000 ft AGL.
ONLY in FM lines or initial conditions.
WS(hwshwshws)/ddd(ff)KT
Indicator, Height/ Direction, Speed

Question 12

What is a Becoming line?

Answer 12

Lines that indicate a change to the predominate forecast meteorological conditions expected to
occur at either a regular or irregular rate at an unspecified time within the period.

Question 13

What is a Tempo line?

Answer 13

Lines used to indicate temporary fluctuations significantly differing from the previously indicated
predominate conditions.

Question 14

What does not go into a becoming line?

Answer 14

A BECMG line will not include Non-Convective Low Level Wind Shear. Also, forecasters should avoid using BECMG lines for forecast conditions that fall below field minimums.

Question 15

Amendment criteria Ceilings

Answer 15

Meet, Exceed or Fall Below:
. 3,000 ft
. 1,000 ft
. 200 ft

Question 16

Amendment criteria Visibility

Answer 16

Meet, Exceed or Fall Below:
. 4,800 meters (3 SM)
. 1,600 meters (1 SM)
. 800 meters (½ SM)

Question 17

Amendment criteria Surface Winds

Answer 17

. Wind speed change of 10 knots or more.
. Directional Change of 30 degrees or more, with wind sustained or gusting above 15 knots.
. Wind speeds or directional change result in the change of the active runway.

Question 18

Amendment criteria WX (TS/RA/Tornadic)

Answer 18

Forecasted for, but did not occur; or not forecasted and did occur.

Question 19

Amendment criteria Non-Convective Low Level Wind Shear

Answer 19

Forecasted for, but did not occur; or not forecasted and did occur.

Question 20

Amendment criteria Minimum Altimeter

Answer 20

When the observed altimeter falls, or is expected to fall, below the original minimum altimeter.