Weather Services Reports and Forecasts

CPL MET

Aim

To learn and understand the meteorological services available to pilots

Objectives

1.State the briefing services available to a pilot 2.State what the different forecasts and reports are and validity periods associated with them 3.Interpret a TAF/TTF/ARFOR/METAR/SPECI 4.Describe how hazardous weather is disseminated to pilot 5.Describe the automatic weather information services available to pilots

1. Briefing services

Briefing services available to a pilot Aviation forecasts can be obtained through many different sources.

They are: • National Aeronautical Information Processing System (NAIPS) • AVFAX • DECTALK • Telephone • Internet • Radio The main source used widely by pilots is NAIPS click this picture

2. Forecasts and reports

Forecasts and reports CAR 239: •

2. Forecasts and reports

Forecasts and reports There are many different types of aviation forecasts and reports Depending on where you go, decides what sort of forecast and report you should carry The forecast should be studied carefully to ensure that the whole flight is carried out legally clear of cloud and the wind is known at the level you will be flying so heading corrections and fuel calculations can be planned

2. Forecasts and reports

Forecast Types The different types of weather forecasts that will generally be used are: • Area forecasts (ARFOR) • Terminal area forecasts (TAF) • Aerodrome reports (METAR and SPECI) • Trend type forecasts (TTF)

2. Forecasts and reports

ARFOR • Issued every 6 hours for each meteorological area • Narrative format • • • An ARFOR must be valid for the period of your flight Cloud height AMSL Wind degrees true

2. Forecasts and reports

TAF A Terminal Aerodrome forecast is a statement of weather conditions expected at an aerodrome for a specified amount of time.

The area covered by a TAF is 5nm from centre of aerodrome A TAF must be valid for the following periods • From 30 minutes prior to your planned ETA • Until 60 minutes after it The wind represented in a TAF is in degrees true Cloud height in a TAF is above aerodrome level

TAF

2. Forecasts and reports

2. Forecasts and reports

METAR AND SPECI A routine report (METAR) and special report (SPECI) are not forecasts, they are in fact an observation of meteorological conditions at aerodromes made by approved observers A METAR is issued at fixed times either half hourly or hourly A SPECI is issued when the actual conditions fluctuate below specified criteria.

Both METAR’s and SPECI’s are available pre flight and also in flight to the pilot upon request.

Cloud height is given above aerodrome level Wind is given in degrees true

2. Forecasts and reports

TTF A Trend Type Forecast (TTF) is defined as a weather report to which a statement of trend is appended.

A TTF relates to weather conditions expected to affect an aerodrome A TTF has a validity of 3 hours following the issue of the report.

Because a TTF is considered to be more accurate, if a TTF is issued, it supersedes the TAF for the validity period.

2. Forecasts and reports

Forecasts and reports

3. How to interpret forecasts and reports Common abbreviations All abbreviations that are used in forecasts can be found in the AIP GEN 2.2, however some common abbreviations are: Further abbreviations can be found in AIP GEN 3.5

3. How to interpret forecasts and reports Forecasts and reports- TEMPO AND INTER TEMPO and INTER indicate significant variations from the previously given conditions, of a temporary or intermittent nature The validity periods of the INTER’s or TEMPO’s can be in the format 0900/0905 (0000 UTC on the 9 th to 0500 UTC on the 9 th ) or 0700/1200 (from 0700 to 1200 hours UTC) A TEMPO is used to indicate a change in prevailing conditions for a period between 30 and 60 minutes An INTER is used to indicate a change in prevailing conditions for up to 30 minutes

3. How to interpret forecasts and reports Forecasts and reports- CAVOK The term CAVOK stands for Ceiling and Visibility ok For the term CAVOK to be used, a few factors need to be met simultaneously.

• Visibility 10km or more • Nil cloud below 5000’ or below the highest minimum sector altitude (whichever is greater) • • No cumulonimbus No precipitation, thunderstorms, fog, snow or dust devils

3. How to interpret forecasts and reports Forecasts and reports- FROM (FM) The term FROM abbreviated FM is used when significant changes are expected. When FM is used, it supersedes all previous information relating to wind direction, vis, weather or cloud.

The conditions given ‘FM’ continue until the end of the validity of the forecast unless another significant change is given.

3. How to interpret forecasts and reports Forecasts and reports- cloud height datum Because an ARFOR can cover a large amount of land with differing terrain, the cloud datum in an ARFOR is above mean sea level (AMSL).

• The actual height of terrain so cloud above ground level (AGL) can be obtained from an approved aviation chart such as a World Aeronautical Chart (WAC) In Terminal Area Forecasts and reports (TAF, TTF, METAR and SPECI) the cloud datum is given above aerodrome level (AAL) Clouds are shown as a 3 figure group of tens of thousands, thousands and hundreds eg: SCT035 indicates scattered cloud at 3500’

4. Hazardous weather

How is hazardous weather relayed to pilots Hazardous weather can be relayed to pilots in a number of ways • SIGMET • AIRMET The information in SIGMET’s can be plotted on a Planning Chart Australia (PCA) to determine whether the hazardous weather is going to affect your flight

5. Automatic weather services

Automatic weather services available to pilots There are numerous ways in which a pilot can get meteorological information from automatic sources. They are: • Automatic Terminal Information Service (ATIS) • Automatic En-Route Information Service (AERIS) • VOLMET • Aerodrome Weather Information Broadcasts (AWIB)

5. Automatic weather services

ATIS The ATIS is a recorded voice message broadcast at certain aerodromes which gives operational information for aircraft operating at that aerodrome It is broadcast on either a discreet frequency or on a voice channel of a radio navigation aid.

When control zones are deactivated the ATIS frequency can be used to broadcast other operational information regarding the aerodrome Information given in the ATIS is: • Runway in use • Wind velocity and direction in degrees magnetic • Altimeter setting • Cloud amount and base • Temperature • Visibility • Any other significant information

5. Automatic weather services

AERIS The AERIS is an automatic transmission of METAR from a network of VHF transmitters around the country.

5. Automatic weather services

VOLMET The AIP extract (AIP GEN 3.5-19): Volmet broadcasts are prefixed by the designator “VOLMET” and may contain: • METAR/SPECI or TTF (when available) and advice regarding the availability of SIGMET Individual volmet broadcasts will not exceed 5 minutes duration Cloud types (excluding cumulonimbus) will not be included in VOLMET.

The locations and availabilities of volmets are as follows:

5. Automatic weather services

AWIB Similar to ATIS, but an aerodrome weather information broadcast (AWIB) is an automatic broadcast of actual weather conditions Usually broadcast on navigation frequencies Similar format to ATIS

Questions?