Chapter 22

Question 1

What are WMOs?

Answer 1

World Meteorologicla Centres monitor the collection of weather data.

They were set up to do this for the ICAO to make sure everyone is being

Question 2

What are WAFCs?

Answer 2

World Area Forecast Centres produce SIGWX and Upper-Air charts. There are 2 - Washington and London

The one in London is the Met Office

Question 3

What are MOs?

Answer 3

Meteorological Offcies produce TAFs (Termianl Area Forecasts). TAFs are forecasts, they report on what the weather looks like it is going to do, not what it is doing

Question 4

What do MSs do?

Answer 4

Meteorological Stations produce METARs (Met Aerodrome Reports) and ATIS. These give real time reports of the weather in the area

Question 5

How long is a TAF valid for?

Answer 5

Anything up to 36 hours

Question 6

How long is a METAR valid for?

Answer 6

1 hour

Question 7

What are MWOs?

Answer 7

Meteorological Watch Offices produce SIGMETs and AIRMETs

Question 8

What are VAAC?

Answer 8

Volcanic Ash Advisory Centres monitor volcanicn action, and monitor the air for dust and ash in plooms

Question 9

What are TCACs?

Answer 9

Tropical Cyclone Advisory Centres monitor for tropical storms. They lock a satellite onto a storm and monitor and track its progress, and release a report. This is combined with a SIGMET from an MWO

Question 10

What do Information Centres/WAFCs Produce? And how often?

Answer 10

They produce upper-air gridded forecasts, and they produce signifcant weather (SIGWX) charts every 6-9 horus, reporting on :
- Wind, temperature and humidity
- Tropopause height and temperature
- Areas of significant weather (CB (thunderstorms), Icing, Turbulence etc.)

Question 11

Who makes SIGWX for Low Levels?

Answer 11

For below FL100 or FL150 in mountainous areas, they are produced by the Meteorological Offices

Question 12

What do Meteorological Offices (MOs) do?

Answer 12

They produce TAFs every 3-6 hours and they issue a Low Level Forecast every 6 hours if required (as a GAMET either as text or a chart)

Question 13

How long are TAFs Valid For?

Answer 13

6-30 hours depending on the country

Question 14

What are Meteorological Stations?

Answer 14

They are usually airport based centres who provide a METAR every 30 mins and MET reports. They also, depending on circumstances:
- Issue a SPECI
- Issue a trend/landing forecast whcih is valid for 2 hours
- Issue a SNOWTAM, warning of snow, slush and ice, which is valid for up to 8 hours
- Issue Aerodrome Warning (ADW) for condtitions affecting aircraft, facilities and vehicles on the ground

Question 15

What do MWOs Produce?

Answer 15

• SIGMET - upper level reports, valid for 4-6 hours
• AIRMET - low level reports for up to FL100 (FL150 in mountains) and are valid for 4 hours
• ASHTAM - warnings of volcanic activity and ash, valid for 24 hours

Question 16

What are Gridded Forecast Products?

Answer 16

They are world area forcests, using numerical predictions on a 3D grid, with horizontal (lat and long) and vertical (height and pressure) data

Horizontal is Latitude and Longitude, mapping out the area not taking in

Question 17

What are Volcanic Advisories?

Answer 17

VVA reports are reports that can be in both graphical and text form. Red shows where ash currently is and green shows where it is heading

Question 18

What are Tropical Cyclone Advisories?

Answer 18

Reports where a cyclone is tracked on a map. It shows where it currently is and where it is heading

Question 19

What is an ASHTAM?

Answer 19

Provides informaiton on the status of volcanos when there is or expected activity. It is rated on a traffic light system, with ash clouds at FL250 or predicted to reach above FL250

Question 20

What is a SIGMET?

Answer 20

A warning of dangerous meteorological conditions produced by a MWO (Exeter for UK) and issued by a Meteorological Station

An MS is usually at an aerodrome

Question 21

What do SIGMETs Report on?

Answer 21

• Thunderstorms (TS) - Obscured (OBSC), Embedded (EMBD) and Frequent (FRQ)
• Tropical Cyclone (winds +34ktd above cyclone)
• Severe Turbulence
• Severe Icing
• Severe Mountain Waves
• Heavy Sand and Dust Storms
• Volcanic and Radioactive Clouds

TSs can be Isolated (<50%), Occasoinal (50-75%) or Frequent (>75%)

Question 22

How does a SIGMET Report get Reported?

Answer 22

A pilot passes information about weather on to ATC, who then relays it to a MWO. If needed, it can be passed to a WAFC, then the MWO will issue and supply ATC with a SIGMET

Question 23

What is a METAR?

Answer 23

A report of the current conditions at a specific time. They are issued hourly, but can be more frequent, and can be automated.

Question 24

What is a SPECI?

Answer 24

A report the same as a METAR, however, it is only issued when there is a significant change in weather between reports.

Question 25

What is a VOLMET?

Answer 25

It is an in flight weather report on HF or VHF radio. It can provide a TAF, SIGMET and METAR

Question 26

Where are HF VOLMETS used and what do they do?

Answer 26

They are a report that runs to a shedule, with 5 minute time slots for each aerodrome. It runs every half hour and is predominantely in Oceania, so Austraila and New Zealand

Question 27

How does a VHF VOLMET run?

Answer 27

In a loop

Question 28

What is ATIS?

Answer 28

Automatic Terminal Information Service. It’s a plain langauge take off and landing report prepared by ATC at a controlled aerodrome. It is issued whenever there is a weather condition change, and is given the next letter in the alphabet.

Question 29

What is a PIREP Pilot Report?

Answer 29

Whenver experiencing a change in weather condition, a pilot must report it to ATS, even if another pilot has reported it. It includes:
- Wind Shear
- Volcanic activity
- Morderate to severe turbulence
- Moderatre to severe icing
- Moderate to severe mountain waves
- Thunderstorms
- Heavy dust/sand storms