Meteorological Services for Aviation

Meteorology · Chapter 21 · DGCA CPL and ATPL

Who in India and the world makes the weather information you fly on, what each product is, how long it is valid and when you have to ask for it.

Remember

WMO + ICAO; World Weather Watch (GOS, GTS, GDPS). WAFS: 2 WAFCs (Washington, London), 19 RAFCs (one New Delhi); products 4 a day, within 6 h.
IMD: 6 RMOs, 18 AMOs (incl. 4 MWOs: Delhi, Mumbai, Kolkata, Chennai), 54 AMSs, TCAC, OLBS.
Notice (non-scheduled): national AMO 3 h, AMS 18-24 h; international main offices 3 h, other AMOs 12 h, AMS 18-24 h.
AIREP section 3 = weather; exempt: no RNAV, ≤ 2 h flight, ≤ 1 h to land, below 1500 m. Nowcast 10 d.
TREND 2 h; take-off forecast within 3 h, 2-min wind; local/area forecasts 3 a day, 12 h, 50/100 NM. SIGWX: WAFC global, MWO Chennai national; high FL250-630, medium FL100-250; 4 a day, 24 h.
SIGMET: MWO, in flight, ≤ 4 h (VA/TC 12 h ahead, 6-hourly). AIRMET/GAMET: low level. ISOL 75%.
Aerodrome warning ≤ 4 h: 30 kt or a 20 kt wind turning 45°. Light aircraft 17 kt. Wind shear warning to 500 m. VOLMET: Mumbai and Kolkata, half-hourly; ROBEX outside India.

Who makes the weather information a pilot uses?

Who provides aviation weather

Follow the weather data from the whole world down to your airport. Tap Next.

WMO and the World Weather Watch Weather services for aviation have one aim: safe and efficient flying. The World Meteorological Organization (WMO), a UN agency, works with ICAO on this. It links weather stations and services, speeds up the exchange of data, and supports research and training. Its World Weather Watch has three parts. The Global Observing System (GOS) takes the observations, the Global Telecommunication System (GTS) carries them round the world, and the Global Data Processing System (GDPS) turns them into analyses and forecasts.
WAFS The World Area Forecast System (WAFS) gives every met office the same global forecasts for flights en route. Two World Area Forecast Centres (WAFCs), in Washington and London, make them. 19 Regional Area Forecast Centres (RAFCs) pass them on; one is in New Delhi. The WAFCs send gridded forecasts of upper winds, temperature, humidity, the tropopause, maximum wind, icing, turbulence and CB, plus SIGWX charts and news of radioactive releases and volcanoes. They do this 4 times a day, each set within 6 hours.
IMD In India the service comes from the India Meteorological Department (IMD), through 6 Regional Met Offices (RMOs). At 18 major airports an Aerodrome Met Office (AMO) keeps watch 24 hours a day. It issues METAR and SPECI, RVR, TAF, TREND and warnings, briefs crews, and feeds VOLMET, ATIS, radar and satellite pictures. 54 smaller Aeronautical Met Stations (AMSs) observe the weather and pass on their AMO's forecasts during their working hours.
MWOs, TCAC and OLBS Four AMOs, at Delhi, Mumbai, Kolkata and Chennai, are also Meteorological Watch Offices (MWOs). Each one watches its Flight Information Region (FIR) and issues SIGMET. The Tropical Cyclone Advisory Centre (TCAC) tells ICAO users where a cyclone is, how it moves, its central pressure and its winds. The Online Briefing System (OLBS) puts it all on the web: winds and temperatures FL50-FL530, 9 h and 30 h TAFs, national and WAFC SIGWX, METARs, satellite and radar pictures, synoptic features, T3 route forecasts for low flights, local and area forecasts, take-off data and SIGMET.

Memory hook: 2 WAFC · 19 RAFC · 6 RMO · 18 AMO · 4 MWO · 54 AMS.

Takeaway: The WMO, working with ICAO, runs the World Weather Watch: GOS observes, GTS shares and GDPS processes. WAFS makes the global forecasts for flights en route: 2 WAFCs (Washington, London) and 19 RAFCs, one in New Delhi. In India, IMD has 6 RMOs, 18 AMOs (4 of them MWOs), 54 AMSs, a TCAC and the online briefing system, OLBS.

Who in India makes the weather you fly on?

India's met network

A map story in five steps. Tap Next, or tap any office.

WAFS: forecasts for the whole planet Under the WMO's World Weather Watch, the World Area Forecast System gives every met office global en-route forecasts. Two World Area Forecast Centres, at Washington and London, make gridded upper winds, temperatures, humidity, tropopause, maximum wind, icing, turbulence, CB and SIGWX forecasts, 4 times a day. They are helped by 19 Regional Area Forecast Centres; one of them is New Delhi.
Six regional offices The India Meteorological Department has 6 Regional Met Offices: Delhi, Mumbai, Kolkata, Chennai, Guwahati and Nagpur. For aviation it runs 18 Aerodrome Met Offices (AMOs) at the major airports, with 24-hour watch, and 54 Aeronautical Met Stations (AMSs) that observe and pass on forecasts from their AMO.
Four Met Watch Offices Four of the AMOs are also Meteorological Watch Offices: Delhi, Mumbai, Kolkata and Chennai. Each watches the weather over its Flight Information Region and issues SIGMET for aircraft in flight there. MWO Chennai combines the four offices' charts into one national SIGWX chart for medium and high levels. SIGMET issuers: the 4 MWOs (Delhi, Mumbai, Kolkata, Chennai). National SIGWX compiled by MWO Chennai.
Weather on the radio, west VOLMET broadcasts weather to aircraft in flight. India's HF VOLMET is broadcast in turn every half hour from Mumbai and Kolkata. Mumbai's broadcast includes METARs for Mumbai, Ahmedabad, Chennai, Colombo, Karachi and Male, and TAFs for Mumbai, Male and Colombo.
Weather on the radio, east Kolkata's broadcast includes METARs for Kolkata, Delhi, Dhaka, Yangon and Kathmandu, and TAFs for Kolkata, Delhi and Ho Chi Minh City. Data-link VOLMET (D-VOLMET) sends METAR, SPECI, 9-hour TAF, SIGMET, special AIREPs and AIRMET to the cockpit.

Takeaway: WAFCs make global forecasts; IMD's AMOs watch and forecast for airports; the 4 MWOs watch the FIRs and issue SIGMET; VOLMET broadcasts it all to aircraft in flight.