ATC Basics: Forecasts & Advisories

What is a concise statement of the expected meteorological conditions significant to an airport for a specified time period that’s used to anticipate weather changes that will affect aircraft operations at specified terminals?

TAF (terminal aerodrome forecast)

What is the radius of a TAF?

5nm from the airport

What is one particular weather event that the TAF is mainly responsible for?

LLWS

What 3 parts of the METAR are not included in the TAF?

1. Temperature/dew point

2. Altimeter

3. Remarks

Is TAF scheduled or unscheduled?

Scheduled

How often does a TAF come out?

Every 6 hours (so 4 times per day)

How is a TAF denoted to show that it’s been amended?

TAF AMD

What times does a TAF come out at?

000, 0600, 1200, and 1800Z

How is a TAF denoted to show it’s been corrected?

TAF COR

How long is a TAF valid for?

24 or 30 hours

In this example TAF, what is:

1. The location

2. Date & time of the most recent report

3. The time the most recent report is valid for

4. The most recent wind group

5. The most recent visibility

6. The clouds & vertical obscuration group

1. KOKC

2. 30th day, 23:20Z

3. Valid from 00-24 (so 24 hours, from 12a-12a)

4. Wind 160 at 9 knots

5. Visibility greater than 6

6. 3500 scattered, ceiling 700 broken, 15000 overcast

When is a TAF valid for 30 hours?

Airports with significant international traffic

If an airport is smaller, how long is their TAF valid for?

24 hours

How high will visibility go in a TAF, and how do you denote it’s higher than that?

6, P6SM

How is clear skies represented on a TAF?

SKC

How close must LLWS be to the surface to be included in a TAF?

Within 2,000ft

If LLWS doesn’t occur, what happens to the group in a TAF?

It’s omitted

If the LLWS group on a TAF shows WS020/18040KT, what is:

1. Indicator for wind shear

2. Height of the top of the WS

3. Wind direction

4. Wind speed

1. WS

2. 2,000ft

3. 180

4. 40

What is the unit of measurement for the LLWS group in a TAF?

AGL

What is the abbreviation used to characterize a change indicator group that’s used to indicate a significant & rapid change to a new set of prevailing conditions in a TAF?

FM (from)

What elements are included on the FM group, regardless of whether they’re forecasted to change?

All elements

In this example TAF, what are:

1. The 3 FM groups’ issuance dates & times

2. The 3 FM groups’ wind interpretations

3. The 3 FM groups’ prevailing visibilities

4. Clouds/significant weather for FM group 1

5. Clouds/significant weather for FM group 2

6. Clouds/significant weather for FM group 3

7. Wind shear group from group 3

1. From the 1st day of the month at 0700; from the 1st day of the month at 1700; from the 2nd day of the month at 0100

2. Wind 220 at 7; wind 220 at 11 gusts 20; wind 220 at 8

3. All over 6 statute miles

4. Ceiling 18000 broken

5. Scattered 8000, ceiling broken 15000

6. Ceiling broken 8000

7. Low-level wind shear, wind at 2000, 250 at 35

If asked about a time that’s between two FM groups, what group should you look at?

The one above the time

What change indicator is used to indicate temporary fluctuations to forecast meteorological conditions in a TAF?

TEMPO

What weather elements need to be in a TEMPO group?

Only those that are changing

In this example TAF, what are:

1. The 2 tempo groups’ condition beginning & ending times

2. The weather expected in group 1

3. The weather expected in group 2

1. From the 1st day at 00-the 1st day at 03; from the 1st day at 03 until the first day at 07

2. Thunderstorm, rain, mist; 1500 scattered, ceiling 3500 broken, 7000 overcast

3. Wind variable between 20-40 (gusts); thunderstorm, heavy rain, mist; ceiling 1200 broken

What group is used to forecast a low probability of a thunderstorm or precipitation event and its associated weather elements?

PROB30

Where will the PROB30 group be located?

Within the same line as the prevailing condition

In this example TAF, what is the PROB30 group saying?

From the 1st day at 10 until the 1st day at 14, there’s a 30% chance for light rain showers

What are the 3 types of in flight advisory reports?

1. SIGMET

2. Convective SIGMET

3. AIRMET

For all in-flight advisories, are heights MSL or AGL?

MSL

What is a weather advisory concerning weather significant to the safety of all aircraft?

SIGMET

How much of an area must conditions affect in order for a SIGMET to be issued?

3,000 square miles

What are the 2 main types of weather phenomena that SIGMETs are issued for within the contiguous US?

1. Severe (or greater) turbulence

2. Severe icing

Outside of the CONUS, what 3 things are SIGMETs issued for, in addition to basic conditions?

1. Thunderstorm

2. Tropical cyclone

3. Radioactive cloud

Is a SIGMET scheduled or unscheduled?

Unscheduled

How long is a SIGMET valid for?

4 hours

When can a SIGMET be valid for 6 hours?

Volcanic ash or tropical cyclone outside of CONUS

How do SIGMETs for continuing phenomena work?

Reissued at least every 4 hours while conditions continue

In this example SIGMET, what is:

1. The area identifier

2. The SIGMET series

3. The product identifier

4. The issuance date/time

5. The ending date/time

6. The phenomenon location

7. The phenomenon description

Note: the word cut off is “possible”

1. MKC

2. C

3. WS

4. Issued on the 30th day of the month at 23:55

5. Valid until the 1st day of the month at 01:55

6. TX, OK

7. Severe thunderstorm moving from 240 at 25, tops above FL450; hail up to 1.5 inches; wind gusts up to 60kt possible

What is a weather advisory concerning convective weather significant to the safety of all aircraft?

Convective SIGMET

Where are convective SIGMETs issued?

In CONUS

What weather event are convective SIGMETs issued for?

Thunderstorms

What are the 3 main conditions for a thunderstorm to need a convective SIGMET?

1. Winds at 50 knots or greater

2. Hail ¾ inch of diameter

3. Tornadoes

What is the McDonald’s order for a convective SIGMET?

50 piece McNugget (knots) with ¾ pounder (hail diameter) and a McFlurry (tornado)

For a line of thunderstorms to qualify for a convective SIGMET, how big does it need to be? 2 things

1. At least 60 miles long with thunderstorms affecting at least 40% of its length

2. Affecting at least 3,000 square miles with thunderstorms affecting at least 40% of its length

If there’s a severe thunderstorm OCONUS, what would it be filed under?

SIGMET

What are the 3 convective SIGMET bulletins that tell us which region the weather is occurring in?

E, C, W

Are convective SIGMETs scheduled or unscheduled?

Scheduled

How often do convective SIGMETs come out & at what time?

Hourly at 55 minutes past the hour

How long are convective SIGMETs valid for?

2 hours (unless they’re superseded by the next hourly issuance)

If there aren’t any storms, what will the convective SIGMET look like?

“CONVECTIVE SIGMET…NONE”

What is an in-flight advisory concerning weather phenomena that are of operational interest & potentially hazardous to all aircraft (especially smaller planes)?

AIRMET

What weather is more severe: the weather considered by an AIRMET or the weather considered by a SIGMET?

SIGMET

Is AIRMET scheduled or unscheduled?

Scheduled

What are the three basic types of AIRMETS?

1. Sierra

2. Tango

3. Zulu

What does AIRMET Sierra cover?

IFR (I can’t See!)

What does AIRMET Tango cover?

Turbulence

What does AIRMET Zulu cover?

Icing (freeZe)

What does WA mean?

Weather Airmet

What does WS mean?

Weather SIGMET

What does WC mean?

Weather convective

How long is an AIRMET valid for?

6 hours

What is an unscheduled flight advisory issued for pilots by the CWSU meteorologists for ATC use to alert pilots of existing or adverse weather conditions within the next 2 hours?

CWA

Is CWA scheduled or unscheduled?

Unscheduled

How long is CWA valid for?

2 hours

Is CWA a flight planning product?

No

What are the 4 types of thunderstorms covered by a CWA?

1. Severe

2. Embedded

3. Line

4. Area

What are the 2 types of icing & turbulence covered by CWA?

1. Moderate

2. Severe

What would non-convective LLWS be under?

CWA

What is an unscheduled discussion product issued by CWSU meteorologists that summarizes anticipated weather conditions with potential impact on AT flow control & flight operations in an ARTCC’s area of responsibility?

MIS

How is MIS coded?

Plain language

Is MIS intended for use by pilots?

No

Is MIS scheduled or unscheduled?

Unscheduled

How long is MIS effective for?

Up to 2 days

What 5 characteristics of thunderstorms are considered in a MIS?

1. Timing

2. Tops

3. Movement

4. Intensity

5. Character

What is a computer-generated forecast of wind direction, wind speed, and temperature at selected times, altitudes, and locations?

FB

What does the FB help controllers prevent?

CAT

In this example FB, what is the pertinent information from:

1. HSV at 6000’

2. MGM at 39,000’

3. MOB at 3000’

NOTE: The order of the measurements goes:

3000 6000 9000 12000 18000 24000 30000 34000 39000

1. Wind 170 at 13, temperature 17

2. Wind 010 at 56, temperature -53

3. Wind 120 at 15

At what altitude will temperature NOT be recorded in a FB?

3000

If you see 9900, what does that mean in a FB?

Winds light & variable

In this example FB, what is the pertinent information for:

1. GGW at 34,000’

2. GPI at 39,000’

3. BAM at 12,000’

NOTE: The order of the measurements goes:

3000 6000 9000 12000 18000 24000 30000 34000 39000

1. Wind 270 at 100kts, temperature -48

2. Wind 290 at 103kts, temperature -59

3. Wind 330 at 10kts, temperature 7