Aerodrome Weather Observer

Transcription

1 Aerodrome Weather Observer METARAWS/SPECIAWS Reporting and Recording Bureau of Meteorology Training Centre

2 Commonwealth of Australia 2016 This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced without prior written permission from the Bureau of Meteorology. Cover Photo: P Toomey AWO: METARAWS/SPECIAWS Reporting and Recording Version 3.0, August 2016 BMTC, GPO Box 1289, Melbourne, Victoria, 3001

3 Contents Introduction METARAWS/SPECIAWS Codeform Aerodrome weather report format Message type Location CCCC Date/Time YYGGgg Wind dddff/f m f m KT d N d N d N Vd X d X d X Visibility * VVVV V N V N V N V N D V Runway Visual Range RD R D R /V R V R V R V R i RD R D R /V R V R V R V R VV R V R V R V R i Present Weather w'w' Cloud N S CCh S h S h S or NSC or VVh S h S h S CAVOK Temperature and Dew Point Temperature TT.T/T d T d.t d QNH P H P H P H P H.P H Supplementary Information Remarks RMK Decoded METARAWS/SPECIAWS example METARAWS/SPECIAWS to METAR/SPECI conversion Aerodrome weather reports without manual input WebConsole, MetConsole and the A i

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5 Introduction Aerodrome Weather Observer Class A Certificate holders are accredited to provide Aerodrome Meteorological Reports in the Aerodrome Weather Report format. This reporting format is disseminated via the METAR/SPECI code form. METAR/SPECI reports originate in the METARAWS/SPECIAWS code form. Class A Observers must be familiar with both codes. This supplement contains information on the METARAWS/SPECIAWS code form as well as details on its conversion to the METAR/SPECI format. Also in this supplement is introductory information on the Bureau s observations data entry consoles, MetConsole and WebConsole. Class A Observer course participants should familiarise themselves with a basic understanding of the use of these consoles. Prior to commencing AWO Practical: Class A, check with the staff at your intended course location whether MetConsole or WebConsole is in use so you can focus your study. Finally, an introduction to the paper record, the A37 Register of Weather Reports, is included in the supplement. All Aerodrome Weather Reports provided in the field are recorded on this register. The information contained within this pdf is assessed during AWO Practical: Class A. Consult the course competencies for further details. 1

6 1 METARAWS/SPECIAWS Codeform One of the purposes of performing a weather observation is to provide information for inclusion in an Aerodrome Weather Report for transmission in the METAR/SPECI format. Aerodrome Weather Reports are usually produced on a half-hourly routine reporting schedule, with intervening non-routine reports (SPECI) being transmitted when certain thresholds are met. This topic describes the METARAWS/SPECIAWS code form in detail. METARAWS/SPECIAWS and METAR/SPECI METARAWS is the name of the code for a routine aerodrome weather report from an Automatic Weather Station (AWS) with or without manual input. SPECIAWS is the name of the code for a special aerodrome weather report from an AWS with or without manual input. SPECIAWS reports are issued when changes in meteorological parameters meet specific criteria. Manual input involves a certified observer adding value to an observation by including more detailed information on items such as visibility, weather and cloud. This information is usually entered and transmitted via a MetConsole or WebConsole computer terminal at the observing office. (Introductory information on data entry for MetConsole, WebConsole and the A37 form is contained in Appendix 2). Prior to dissemination to aeronautical users, the METARAWS/SPECIAWS code is converted to the METAR/SPECI code. The main differences between the METARAWS/SPECIAWS and METAR/SPECI codes relate to the format in which the information is coded, as well as variations in the amount of information that is included. Some of these differences involve the encoding of wind gusts, cloud, rainfall and the rounding of data. The METARAWS/SPECIAWS also includes information relevant to technicians for the setting of various thresholds and monitoring of AWS components. Class A Aerodrome Weather Observers are required to be familiar with both the METARAWS/SPECIAWS and METAR/SPECI code forms. METAR/SPECI reports are available from a number of sources including the Airservices Australia Pilot Briefing web pages as well as the Bureau of Meteorology s external web pages. Note: There are currently two versions of the METARAWS/SPECIAWS code being disseminated from Bureau sites: Code form versions 2.2 and 2.4. These notes use the newer code (2.4) as the foundation for describing the METAR/SPECI code. Where a significant variation exists between the two code forms an asterisk (*) is used to denote those differences. Users with access to the METARAWS/SPECIAWS code form will find the code version number embedded in the code itself. 2

7 1.1 Aerodrome weather report format CODE FORM: Version

8 1.1.1 Message type A METARAWS is a routine report of meteorological conditions at an aerodrome. A SPECIAWS is a special report of meteorological conditions, issued when one or more elements meet specified criteria significant to aviation. SPECIAWS is also used to identify reports of observations following an improvement (in visibility, weather or cloud) to above SPECI conditions. SPECIAWS reports may be issued at any time, including routine reporting times Location CCCC The reporting station is indicated by the ICAO location indicator where one exists. Otherwise it will be one proposed by the Regional Observations Manager in consultation with the Network Operations Group Date/Time YYGGgg The date/time group is reported in hours and minutes Coordinated Universal Time (UTC) using six figures. The first two digits refer to the day of the month, the next two the hour, and the last two the minutes. For a routine Aerodrome Weather Report (METARAWS/METAR) the Time of Observation is the 10 minute period leading up to the reported time, during which the observation is made. An observer must consider any phenomena observed during this 10 minute period when determining what to include in a report. For special weather reports (SPECIAWS or SPECI), the time of observation is the time of occurrence of the change(s) which justified the issue of the report. 4

9 1.1.4 Wind dddff/f m f m KT d N d N d N Vd X d X d X Wind direction ddd Wind direction indicates the direction from which the wind is blowing in degrees true (geographic, not magnetic). The wind direction (and speed) in a METARAWS is usually averaged over a 10 minute period by the AWS. This is known as the Wind Assessment Period (WAP). If a marked wind discontinuity is detected during that 10 minute period, the length of the period will be correspondingly reduced. For a wind direction or wind speed SPECIAWS (described in a later section), the length of the wind assessment period will always be 2 minutes. For all other SPECIAWS, the wind assessment period will vary between 2 and 10 minutes. The direction is reported to the nearest 10 in the METARAWS/SPECIAWS message. Note: Wind direction follows the rule of rounding to odd when the last digit is a 5 (E.g. 015 is rounded to 010 and 025 is rounded to 030). When the last digit is not a 5, standard mathematical rounding applies. In the case of a variable wind, the direction (ddd) may be encoded as VRB when the mean wind speed is 3 knots or less, and a direction cannot be determined. Wind speed ff Wind speed is measured and reported in knots. The wind speed is averaged as per the WAP details indicated above. Calm winds are encoded as 00000KT in an Aerodrome Weather Report. Maximum wind speed (gust) f m f m A gust is a rapid increase in the strength of the wind compared to the mean speed, and of lesser duration than a squall. In a METARAWS/SPECIAWS, the maximum wind gust in the WAP is always included in the message. In the METAR/SPECI message format for aeronautical users, only gusts 10 kt or more above the mean speed are included. Variation in direction * d N d N d N Vd X d X d X If, during the WAP, the total variation in wind direction is 60 degrees or more but less than 180 degrees and the mean wind speed is 3 knots or more, the observed two extreme directions between which the wind has varied shall be given by d N d N d N Vd X d X d X in clockwise order. Otherwise this group shall not be included. * Note: d N d N d N Vd X d X d X is not used in the METARAWS/SPECIAWS version 2.2 code form. 5

10 1.1.5 Visibility * VVVV V N V N V N V N D V Horizontal visibility is the meteorological optical range and is expressed in metres using four digits. Prevailing visibility VVVV VVVV reports prevailing visibility, which is the greatest visibility reached within at least half the horizon circle. Minimum visibility V N V N V N V N D V V N V N V N V N D V reports any lowest visibility and its general direction (using one of the eight points of the compass) in relation to the meteorological office. How to report visibility VVVV is always reported, unless the visibility is fluctuating rapidly such that a prevailing visibility cannot be determined. In this case only the lowest visibility is reported, as V N V N V N V N with no indication of direction. VVVV and V N V N V N V N D V are both reported when: a. the visibility is not the same in different directions and is not fluctuating rapidly; and b. the lowest visibility is not the prevailing visibility, and c. the lowest visibility is less than 1500 metres, or i. less than 5000 metres and ii. less than 50% of the prevailing visibility If the lowest visibility is observed in more than one direction, the most operationally significant direction shall be reported. Rounding Horizontal visibility will be reported: a. in steps of 50 metres when it is less than 800 metres, b. in steps of 100 metres when it is 800 metres or more, but less than 5000 metres, c. in steps of 1000 metres when it is 5000 metres or more, but less than metres, d. as 9999 when it is metres or more. All observed values are to be rounded down to the nearest lower step in the scale. * Note: When both reported, prevailing visibility and minimum visibility are coded in reverse order in code form version 2.2, ie V N V N V N V N D V VVVV. See Observations Instruction 13/05 for further information. The Visibility Flow Diagram over page summarises the procedure to report visibility in Aerodrome Weather Reports. 6

11 Flow diagram for reporting visibility 7

12 1.1.6 Runway Visual Range RD R D R /V R V R V R V R i RD R D R /V R V R V R V R VV R V R V R V R i Runway Visual Range has been defined by ICAO as the maximum distance in the direction of take-off or landings at which the runway or the specified lights or markers delineating it, can be seen from a position above a specified point on its centre line, at a height corresponding to the average eye-level of pilots at touch down. RVR measurements are required to be representative of conditions at and near the threshold for takeoff and landing, and other parts of the runway as required. RVR is only included in Aerodrome Weather Reports at locations with RVR instrumentation and where procedures have been put in place to do so. It is reported whenever the RVR or the prevailing visibility is less than 1500 metres. RVR is only approved for use during low visibility conditions characterised by mist or fog. It should not be reported during other types of obscuration such as heavy rain, dust or smoke. RVR code format The RVR at a runway s threshold will be given by RD R D R /V R V R V R V R i, or RD R D R /V R V R V R V R VV R V R V R V R i R is a fixed indicator. D R D R is the designator for the runway threshold to which the RVR value refers. Parallel runways are distinguished by appending the letters L, C or R indicating the left, centre or right parallel runway, respectively. i will indicate any distinct tendency of the RVR. This shall be indicated by U for upward tendency or D for downward tendency. When no distinct change in RVR is observed, i = N shall be used. When it is not possible to determine the tendency, i shall be omitted. RD R D R /V R V R V R V R i will be reported when there are no significant discontinuities during the 10 minute reporting period over which the RVR value is valid. In this case V R V R V R V R shall report the mean value of the RVR over the 10 minute period immediately proceeding the observation time. RD R D R /V R V R V R V R VV R V R V R V R i will be reported instead of RD R D R /V R V R V R V R i, when the RVR at a runway varies significantly during the 10-minute period preceding the observation time. V R V R V R V R VV R V R V R V R i shall report the minimum 1-minute mean RVR value, followed by the fixed indicator V, followed by the maximum 1-minute mean value, followed by the tendency as required. The RVR value shall be reported as: o o P2000 when it is assessed to be more than 2000 metres. M0050 when it is assessed to be less than 50 metres. Below is an example of the inclusion of RVR in an Aerodrome Weather Report: SPECIAWS YMML /07KT E R16/0750VP2000U R27/P2000N BCFG 5ST / RMK RF00.0/000.0 CLD:BKN001 VIS:1300BV:13.5 IT:20.9 8

13 1.1.7 Present Weather w'w' The present weather information includes phenomena occurring at the time of observation at or near the local area, ie., either within 8 km of the aerodrome reference point, or in the vicinity and of significance to aeronautical operations. Coding present weather The present weather group is constructed by considering columns 1 to 3 in the table below in sequence, ie., intensity or proximity (if appropriate), followed by a weather description (if appropriate), followed by the weather phenomena. Up to three groups of present weather can be reported in an Aerodrome Weather Report. INTENSITY or PROXIMITY INDICATORS 1 WEATHER DESCRIPTOR 2 SIGNIFICANT WEATHER PHENOMENA 3 - Light Moderate (no symbol) + Heavy Intensity indicators can only be used for reporting precipitation, duststorms sandstorms and funnel clouds MI Shallow (below 2 metres) Used with FG only if visibility is not obscured at 2 metres above the ground due to fog BC Patches Used with FG PR Partial Used with FG DZ RA SN SG PL GS GS Drizzle Rain Snow Snow Grain Ice Pellets Small Hail Snow Pellets Precipitation VC In the Vicinity DR Drifting (below 2 metres) Used with DU, SA and SN GR Hail (not at the aerodrome but between 8 and 16 km from the Aerodrome Reference Point) VC is only used with TS, DS, SS, FG, FC, SH, PO, BLDU, BLSA, BLSN, VA BL Blowing (above 2 metres) Used with DU, SA and SN SH Showers (precipitation from cumuliform cloud). Used with RA, SN, GS, and GR TS Thunderstorm * (thunder heard or lightning detected and within 8km of the Aerodrome Reference Point) FZ Freezing (super cooled water droplets below 0 C) * Although TS is categorised as a descriptor it can also be used as a weather phenomenon on its own. BR FG VA FU DU SA HZ PO SQ FC SS DS Mist Fog Volcanic Dust Smoke Dust Sand Haze Dust Devil Squall Funnel Cloud Sandstorm Duststorm Obscuration Other 9

14 Additional present weather coding procedures Intensity Indicator The intensity indicator (+ or -) is used with precipitation phenomena (DZ, RA, SN, SG, IC, PL, GS, GR). Precipitation reported without an intensity indicator indicates precipitation of a moderate intensity. Example: -DZ (light drizzle) +SHRA (shower of heavy rain) SN (moderate snow) If an observer is unable to determine the precipitation rate with any appreciable accuracy (for instance if the precipitation is occurring close to, but not at the observation site), the intensity indicator is omitted. An observer should do their best however to determine the intensity of such precipitation using cues such as the visibility reduction, etc. SS, DS and FC can also be reported with the heavy (+) indicator, but not the light (-) indicator. In the vicinity Example: +DS or +SS (severe dust or sand storm; visibility < 200m) +FC (tornado or waterspout) The proximity indicator VC is used for weather phenomena are not occurring within 8 kilometres of the aerodrome reference point but between approximately 8 and 16 kilometres away. VC can only be used with TS, DS, SS, FG, FC, SH, PO, BLDU, BLSA, BLSN, VA Example: VCBLDU (blowing dust in the vicinity; 8-16 km away) Multiple phenomena occurring simultaneously If more than one significant weather phenomenon is observed, separate present weather groups shall be included in the report, up to a maximum of three. Example: TSRA VCFC (thunderstorm with rain within 8km of the aerodrome reference point and a funnel cloud between 8 km and 16 km away) However, if more than one form of precipitation is observed, the appropriate letter abbreviations shall be combined in a single group with the dominant type of precipitation being reported first. In such a single group, the intensity shall refer to the total precipitation and be reported with one or no indicator as appropriate. Example: +SNRA (snow and rain mixed; the snow being the dominant precipitation type, with a combined heavy intensity) Showers and fog in the vicinity When showers are in the vicinity of the aerodrome (between 8 km and 16 km away) the type and intensity of precipitation is not specified. Example: VCSH (Showers between 8 and 16 km away, precipitation type and intensity not specified) Similar to the above, the descriptors MI, BC or PR are not included when reporting Fog in the vicinity. Example: VCFG (Used to report fog between 8 and 16 km regardless of whether it is shallow, a patch or a bank) 10

15 Thunderstorms Note: Although TS is categorised as a descriptor it can also be used as a weather phenomenon on its own. The qualifier TS shall be used to report the occurrence of a thunderstorm whenever thunder is heard or lightning is detected within the 10-minute period preceding the time of the report and the storm cloud is within 8 km of the aerodrome reference point. The letter abbreviation TS on its own shall be used to report a thunderstorm within 8 km but no precipitation observed. When appropriate, TS shall be followed without a space by relevant letter abbreviations to indicate any precipitation observed. Eg, TSRA, TSRAGR A thunderstorm is regarded as ceased at the time of the last audible thunder or lightning detection; the cessation is confirmed if the thunder is not heard and/or lightning not detected during the following 10 minute period. VCTS shall be used to report the occurrence of a thunderstorm between approximately 8 and 16 km of the aerodrome reference point whenever thunder is heard or lightning is detected within the 10-minute period preceding the time of the report. Precipitation type and intensity are not indicated when reporting VCTS. Note: If any doubt exists as to whether a storm cloud is within 8 km of the aerodrome reference point or between approximately 8 and 16 km of the aerodrome reference point, then it should be reported as being at the aerodrome, i.e. TS. When thunder is heard and the storm cloud is estimated to be beyond 16 km of the aerodrome, DISTANT THUNDER is reported in the remarks section and no reference to TS is made in present weather. Note: If any doubt exists as to whether a storm cloud is in the vicinity or beyond it, then it should be reported as being in the vicinity, i.e. VCTS. The intensity indicator (+ or -) refers to the intensity of the associated precipitation, not the intensity of the thunderstorm. Example: TS (Thunderstorm with no precipitation) +TSRA (Thunderstorm with heavy rain) Visibility requirements for certain phenomena FG (without a descriptor) shall be reported only when the prevailing visibility due to fog is less than 1000 metres. BR shall be reported only when the prevailing or lowest visibility due to mist is no less than 1000 metres and no greater than 5000 metres. FU, HZ, and DU shall be reported only when the prevailing or lowest visibility due to these phenomena is reduced to 5000 metres or less. BLDU and BLSA shall only be reported when the prevailing or lowest visibility due to these phenomena is no less than 1000 metres and no greater than 5000 metres. A duststorm or sandstorm will be indicated as heavy when the prevailing or lowest visibility is less than 200 metres; and as moderate when the prevailing or lowest visibility is less than 1000 metres but not less than 200 metres. The light indicator will not be used with duststorms and sandstorms. 11

16 1.1.8 Cloud N S CCh S h S h S or NSC or VVh S h S h S N S CCh S h S h S The cloud group N S CCh S h S h S shall be repeated to report cloud in an Aerodrome Weather Report in accordance with the following rules: The number of cloud groups reported shall not exceed three, with the exception of when Cb and/or TCu is present and other certain encoding conditions exist. Cloud information is reported from the lowest to highest layer or mass, except when reporting Cb or TCu as a 4 th layer. The cloud amount (N S ) shall be reported in oktas (1 to 8), with the amount of each cloud layer (mass) determined as if no other clouds were present. The cloud type (CC) shall use the two letter abbreviations for the 11 basic cloud types (three letters for Towering Cumulus) The estimated height of the base of the cloud layer or mass (h S h S h S ) shall be rounded down to the next hundred foot increment and reported in hundreds of feet o Example: 960ft is reported as 009; 3590ft is reported as 035 The selection of cloud layers to be reported shall be in accordance with the following criteria (often referred to as the Cb/TCU rule): o o o o 1st group: The lowest individual layer or mass of any amount; 2nd group: The next individual layer or mass covering more than two oktas; 3rd group: The next higher individual layer or mass covering more than four oktas; Extra groups: Cumulonimbus or Towering Cumulus when observed and not already reported in one of the three groups above. When a layer of cloud is made up of Cumulonimbus and Towering Cumulus clouds with a common cloud base, the amounts shall be combined and reported as Cumulonimbus only. NSC * If there are no clouds of operational significance (that is, cloud below 5000 ft or the highest 25 nm minimum sector altitude* (converted to height above the station), whichever is greater, and no Cumulonimbus or Towering Cumulus at any height), no restriction on vertical visibility and the abbreviation CAVOK is not appropriate, the abbreviation NSC (no significant cloud) shall be used. * Note: Although the Codes Handbook specifies NSC is used in code form version 2.2, in practice MetConsole does not code reports with the NSC group. Alternatively for version 2.2, if there are no clouds present (at any height) and CAVOK is not appropriate, the abbreviation SKC (sky clear) is be used. VVh S h S h S When the sky is obscured by fog, smoke, etc. vertical visibility should be reported in lieu of cloud. If no information exists on the height of the obscuration it shall be reported as VV///. Where information exists, the height of the obscuration shall be reported in units rounded down to the nearest 100 ft. For example, a vertical visibility of 350 ft will be reported as 300 ft and encoded as VV003 in the AWR. 12

17 1.1.9 CAVOK CAVOK is included in an Aerodrome Weather Report in place of visibility, present weather and cloud when the following conditions occur simultaneously at the time of observation: a) visibility of 10 km or more, and conditions do not require the lowest visibility group V N V N V N V N D v to be reported; b) no cloud below 5000 ft or below the highest 25 nm minimum sector altitude* (converted to height above station), whichever is the greater; c) no Cumulonimbus or Towering Cumulus; and d) no significant weather phenomena (as per the table in 7.2.7) *Note: Highest minimum sector altitude (MSA) is defined by ICAO Annex 3 as: The lowest altitude which may be used which will provide a minimum clearance of 300 m (1000 ft) above all objects located in the area contained within a sector of a circle of 46 km (25 nm) radius centred on a radio aid to navigation. The levels are given in Airservices DAP (where instrument procedures exist). The aerodrome s elevation is subtracted from the MSA to obtain the effective value. WebConsole/MetConsole automatically determines whether or not to report CAVOK depending upon what is entered into the cloud, visibility and weather data fields. Sometimes certain weather phenomena may be present at a location but an observer is unable to include it as present weather due to coding procedures. An observer may choose to include such weather information in the Plain Language (RMK) section of the report. Plain Language remarks have no effect on the determination of CAVOK conditions in an Aerodrome Weather Report. When CAVOK conditions prevail and a total of more than 4 oktas of low or middle level cloud covering the celestial dome is present, the detail of this cloud will be given in coded form in the Plain Language section of the message, e.g. 1CU060 4AC110. This is normally automatically encoded into the report. On those occasions where CAVOK conditions prevail and a total of more than 4 oktas of low or middle level cloud exist (as described above), but the rule has excluded the reporting of this cloud, users of WebConsole and MetConsole must manually enter the applicable cloud in the plain language section of the report. (The codes handbook suggests such cloud plain language information will be converted to the FEW, SCT, BKN, OVC format, with no mention of type, for conversion to the METAR/SPECI format. In practice this does not occur). Due to Surface and Horizon Definition, and the White Out phenomenon, the term CAVOK is not used in Antarctica. More than 4 oktas of cloud included as a remark when CAVOK conditions exist 13

18 Temperature and Dew Point Temperature TT.T/T d T d.t d Temperature and Dew Point Temperature are included in the METARAWS/SPECIAWS as a three figure group to the nearest one-tenth of a degree. Temperatures below 0 C shall be preceded by the minus sign, (or MS for MetConsole/code form v2.2) QNH P H P H P H P H.P H The AWS Station Level Pressure is measured using an aneroid cell barometer and is converted to QNH ( Aviation Mean Sea Level Pressure), automatically by the AWS. With the QNH set on an aircraft altimeter subscale, the altimeter will indicate the aircraft s approximate height above sea level. The accurate reporting of QNH in an Aviation Observation and Report (regardless of the reporting mechanism) must be considered absolutely critical. Failure to do so has the potential to result in an incident or accident Supplementary Information Recent Weather REw'w' Information on recent weather is given by the indicator letters RE followed without a space by the appropriate abbreviations to describe the weather phenomena. Up to three recent weather groups can be reported. Intensity descriptors are not used in the Recent Weather code format. For example recent rain, whether moderate or heavy, is coded RERA. The following will be reported as recent weather if observed during the period since the last routine report, but not at the (current) time of observation: Freezing precipitation Moderate or heavy drizzle, rain or snow (including showers) Moderate or heavy ice pellets, hail, small hail and/or snow pellets Moderate or heavy blowing snow (including snow storm) Sandstorm or duststorm Thunderstorm Funnel cloud Volcanic ash * The recent weather section of the Code Handbook differs between code forms 2.2 and 2.4. Code form 2.4 is consistent with the international METAR/SPECI code. These training notes and any AWO assessment tasks are based on code form

19 Recent weather reporting examples A shower of moderate rain during the period since the last routine report, with a shower of light rain at the current time of observation is coded as RESHRA. Heavy rain during the period since the last routine report, with moderate rain at the current time of observation does not meet the recent weather reporting requirements. either moderate or heavy rain occurred both in the recent period and current time of observation. A shower of heavy rain during the period since the last routine report, with heavy rain at the current time of observation does not meet the recent weather reporting requirements the character of the precipitation (showery) is disregarded when determining if a phenomenon is to be reported as recent weather. In this example the rain was heavy both in the recent period and current time of observation. Light drizzle during the period since the last routine report, with nil precipitation at the current time of observation does not meet the recent weather reporting requirements. the drizzle in the recent period is of light intensity therefore it is not reported as recent weather. A thunderstorm with moderate rain during the period since the last routine report, with a shower of light rain at the current time of observation is coded as RETS and RESHRA. when considering recent weather reporting of thunderstorms occurring with precipitation, consider the thunderstorm and precipitation as separate phenomena (there is no such group RETSRA). By convention, the character of any precipitation occurring with thunderstorms is showery if it is to be reported. A thunderstorm with moderate rain during the period since the last routine report, with a shower of moderate rain at the current time of observation is coded RETS. see previous. Wind Shear * WS RWYD R D R or WS ALL RWY Recent information on the existence of wind shear along the take-off path or approach path between the runway level and 1600 ft shall be reported whenever available by the group WS RWYD R D R, where D R D R is the runway indicator. Parallel runways should be distinguished by appending to D R D R letters L, C or R indicating the left, centre or right parallel runway, respectively. If wind shear is affecting more than one runway, additional WS RWYD R D R may be used. If the wind shear is affecting all runways, WS ALL RWY shall be used. Wind shear is always immediately reported in a SPECIAWS upon receipt of its existence. It appears in the supplementary information section of the report (not the RMK section). An example of a windshear report in a SPECIAWS: SPECIAWS YXYZ /25KT CU027 3SC / WS RWY09 RMK RF00.0/000.0/000.0 CLD:SCT027 SCT039 VIS:9999 BV:13.5 IT:26.5 * Note: The wind shear code form described in METARAWS/SPECIAWS Ver 2.4 has been superseded by Observations Instruction 15/02. Refer to the instruction for further details. 15

20 Remarks RMK RMK is a fixed indicator and is included in all reports to indicate additional data follows, e.g. code version number, rainfall data, ceilometer data, visibility meter data, present weather sensor data, plain language, trend type forecast, SPECIAWS threshold criteria, the wind assessment period and message status sub-groups. Of the above, the information of most relevance to aeronautical users of Aerodrome Weather Reports is rainfall data, plain language information and the Trend Type Forecast (where available). Further details on all the data included in the RMK section can be found in the Codes Handbook. Rainfall RFRR.R/R 60 R 60 R 60.R 60 /R 9 R 9 R 9.R 9 The rainfall group above is decoded as follows: The rainfall total in the ten minutes prior to the observation; The rainfall total recorded in the 60 minutes prior to the observation; The rainfall total recorded since 0900 Local Time; all reported in increments of 0.2mm. Upon conversion to the METAR/SPECI format, the 60 minute total is omitted. Plain language Plain language can be included to provide additional information not reported elsewhere. This can include reference to bushfires, the occurrence and location of cumulonimbus clouds and thunderstorms, severe squall line, marked mountain waves and anything considered to be of significance to aircraft operations. References to the distance of phenomena shall be in nautical miles (NM). A common plain language entry involves the reporting of Mist, Haze or Smoke that are excluded from Present Weather reporting rules when the visibility is above 5000m, yet still relevant to the end user. When CAVOK conditions prevail and more than 4/8 low or middle level cloud is present at or above 5000 ft, the cloud amount, type and the base is reported as supplementary information in the Remarks section of the METARAWS/SPECIAWS message. The following text is not allowed in the Plain Language group: :, TTF, VER, NNNN, METAR, SPECI and ZCZC. Trend Type Forecast TTF At some locations, meteorologists append a forecast of expected conditions to the METARAWS/SPECIAWS. This forecast period is (typically) three hours. Only qualified meteorologists are able to produce the TTF. 16

21 1.2 Decoded METARAWS/SPECIAWS example SPECIAWS YMXX /10KT 220V E TSRA 3ST006 3CU035 5CI300 1CB / REGS WS R27 RMK WDM10:262 WSM10:006KT MWG10:010KT RF00.4/015.6/017.8 CLD:SCT009 BKN038 VIS:9999 QFF:10154 BV:13.5 IT:35.8 TS 2NM EAST MOV STH VER:2.4.1 SWV: OID:jbloggs SNT: SP30/10/10/10/5/2/99/00/1417/7000/UI/WAP:10 MSG:8975/348/000/000 The report type is a SPECI for the location YMXX, issued at 0223 on the 5 th day of the month UTC. Wind is blowing from 260 True, with a mean speed of 6kt and a maximum speed of 10kt during the wind assessment period. During this period the direction has varied between 220 T and 300 T. The visibility over half or more of the horizon (prevailing) is 10km or more, with a reduction to 4000m to the east. There is a thunderstorm with moderate rain within 8km of the aerodrome reference point. The reportable cloud covering the celestial dome is 3 oktas of Stratus at 600 ft, 3 oktas of Cumulus at 3500 ft, 5 oktas of Cirrus at 30,000 ft and 1 okta of Cumulonimbus at 3000 ft. The dry bulb temperature is 25.2 C and the dew point temperature is 13.6 C. The mean sea level pressure for aviation purposes (QNH) is hPa. Since the last routine report, but not at the current observation time, there was either moderate or heavy small hail. There is also a report of windshear on runway 27. The 10 minute wind direction, mean speed and maximum gust are 262 T, 6 knots and 10 knots respectively. In the last 10 minutes, 60 minutes and since 9am local time, there has been 0.4mm, 15.6mm and 17.8mm of rainfall respectively. The 30 minute processed ceilometer data indicates 3 to 4 oktas of cloud at 900ft and 5 to 7 oktas of cloud at 3800ft. The visibility meter indicates at 10 minute visibility average of 10km or more. The meteorological mean sea level pressure (QFF) is hPa. The standby battery has a voltage of 13.5V, and the internal temperature of the AWS unit is 35.8 C. The observer has noted the position of the thunderstorm is 2nm to the east of the aerodrome, and it s travelling in a southerly direction. The message is coded in accordance with code form version The software version is The observer, jbloggs, sent the message at 0224 on the 5 th February 2013 UTC. The SPECI threshold criteria are: 30 wind direction change, 10 kt change in wind speed, 10 kt absolute wind gusts, 10 kt relative wind gusts, 5 C temperature change, 2hPa QNH change, rainfall thresholds are not applicable (99/00), the HAM for cloud ceiling is 1417ft and 7000m for visibility. The special event indicator indicates this SPECI was user initiated (UI). The wind assessment period (WAP) for the report is 10 minutes. MSG indicates message status sub-groups. 17

22 1.3 METARAWS/SPECIAWS to METAR/SPECI conversion METARAWS YXYZ /21KT NE SHRA 2CU020 3SC / RERA RMK WDM10:092 WSM10:014KT MWG10:021KT RF00.0/000.2/000.2 CLD:SCT022 SCT046 VIS:9999 BV:13.9 IT:31.7 HAZE VER:2.4.1 SWV: OID:jbloggs SNT: SP30/10/10/10/5/2/99/00/1585/7000/UI/WAP:10 MSG:8979/349/000/000 METAR YXYZ Z 09014KT NE SHOWERS OF LIGHT RAIN FEW020 SCT045 24/17 Q1014 RERA RMK RF00.0/000.2 HAZE Above, a METARAWS has been converted to the METAR format for transmission to aeronautical users. The differences between the two code forms are described below: Date/time group: Z is appended to the METAR, Wind group: Wind gusts must be 10kts or greater above the mean wind speed to be included in a METAR/SPECI. When a gust is included the / is replaced with a G. Present weather group: The abbreviated weather codes are converted to the briefing format when accessed via the Airservices Pilot Briefing website. For example: o o RA reported as LIGHT RAIN BCFG BR reported as FOG PATCHES MIST Cloud group: Amounts are changed from eighths (oktas) to: o 1 2 oktas = FEW o 3 4 oktas = SCT o 5 7 oktas = BKN o 8 oktas = OVC With the exception of Cumulonimbus and Towering Cumulus, the cloud types are not included in a METAR/SPECI. Any CB or TCU will still be indicated in the METAR/SPECI. For example: o o 3CB025 will be coded as SCT025CB 1TCU065 will be coded as FEW065TCU Temperature and dew point group: Rounded to the closest whole value, with 0.5 C rounded up. Negative values are preceded by M. QNH group: Q is appended; figure is truncated to remove the tenths value. For example: o becomes Q1007 RMK group: Only the rainfall and plain language and TTF are included. The 60 minute rainfall figure is omitted from the METAR/SPECI. 18

23 1.4 Aerodrome weather reports without manual input At those locations where a manual observation of visibility, weather, cloud and supplementary information is not added to an Aerodrome Weather Report a completely automated report is generated. The following are examples of a METARAWS and METAR that do not have manual input: METARAWS YBLT /09KT //// 11.4/ RMK RF00.0/000.0/000.0 CLD:OVC062 VIS:9999 BV:13.4 IT:15.9 VER:2.X SP30/10/10/10/5/2/99/00/01/00/1499/4999/WAP:10 MSG:0334/193/999/537 METAR YBLT Z AUTO 02006KT 9999 // OVC062 11/07 Q1023 RMK RF00.0/000.0 The lack of manual input is indicated by //// after the wind information in the METARAWS. In the METAR, it is indicated by the word AUTO after the date/time group. The AWS located at YBLT (Ballarat) has ceilometer and visibility meter equipment installed. This is indicated by the inclusion of cloud and visibility data (CLD:OVC062 VIS:9999) in the remarks section of the METARAWS. This automated data is included in the main body of the METAR message. The // in the METAR indicates there is no Present Weather sensing equipment installed at the location. The following are examples of a METARAWS and METAR with no manual input at a location that does not have a visibility meter, present weather sensor or ceilometer installed: METARAWS YDLQ /15KT //// 13.4/ RMK RF00.2/000.2/000.2 BV:13.4 IT:22.7 VER:2.X SP30/10/10/10/5/2/99/00/01/00/9999/9999/WAP:10 MSG:3819/173/999/322 METAR YDLQ Z AUTO 09013KT //// // ////// 13/11 Q1013 RMK RF00.2/000.2 Note the lack of any manual or automatically sensed cloud, visibility or weather information in the METARAWS above. This in indicated in the METAR message by the forward slashes where visibility, present weather and cloud would otherwise be included. Cloud amount in aerodrome weather reports without manual input As indicated above, a METAR/SPECI AUTO derives cloud information from a ceilometer. When such a report originates from METARAWS/SPECIAWS code form version 2.2, the conversion from oktas to FEW, SCT, BKN and OVC differs to that described in previous sections of these notes. Cloud amount derived from the ceilometer and its associated SCA uses the following conversions: SCT = 1 to 3 oktas; BKN = 4 to 6 oktas; OVC = 7 to 8 oktas. Note: FEW is not used. The Codes Handbook indicates this inconsistency between automatic and manually derived cloud amounts has been rectified for METARAWS/SPECIAWS version 2.4 derived messages and the standard conversions apply (FEW = 1 to 2; SCT= 3 to 4; BKN = 5 to 7; OVC = 8). In practice however, this does not appear to occur. 19

24 2 WebConsole, MetConsole and the A37 This section serves as an introduction on the completion of the of the data fields within WebConsole and MetConsole. as well as introducing the conventions of completing the A37 Register of Weather Reports. Further information on the use of WebConsole and MetConsole can be found in the appropriate sections of the Surface Observations Handbook. Staff should determine the type of display console (and METARAWS/SPECIAWS version code form) being used at their intended workplace prior to commencing AWO Practical: Class A. 20

25 Reporting and Recording Message Type and Time WebConsole WebConsole will automatically code a message as either a METARAWS or SPECIAWS depending on the conditions detected by the automated sensors in the AWS. Where appropriate, the message type can be changed by using the drop-down box in the Control Panel section of the METARAWS/SPECIAWS screen. MetConsole MetConsole will automatically code a message as either a METARAWS or SPECIAWS. Where appropriate, the message type can be changed by an observer using the drop-down box in the lower left corner of the MetarAWS screen. A37 Register of Weather Reports SPECI 0100 METAR 2300 The letters AWS are not used when recording METAR and SPECI reports on the A37. METARs are recorded in black or blue ink, SPECIs in red ink. 21

26 Reporting and Recording Wind WebConsole Wind data from the AWS is automatically encoded into the message. The wind assessment period (WAP) for the observation is also shown in the message. Aside from a QC check of the data, no action is required from the observer. MetConsole Wind data from the AWS is automatically encoded into the message. The wind assessment period (WAP) for the observation is also shown in the message. Aside from a QC check of the data, no action is required from the observer. A37 Register of Weather Reports The column titled Min. is not used CALM In the event of a calm wind, ie., 00000KT in the METARAWS/SPECIAWS, write the word CALM in the direction column. Wind speeds less than 10 kt are recorded with a leading zero. Eg 8 kt is recorded as 08 22

27 Reporting and Recording Visibility WebConsole Visibility data is entered in accordance with the visibility flow diagram. VVVV Data entry: Prevailing visibility in metres; or minimum visibility under rapidly fluctuating visibility conditions where the prevailing visibility cannot be determined. Note: The codes handbook states that V N V N V N V N (without a direction) indicates the minimum visibility under fluctuating conditions where the prevailing visibility cannot be determined. Regardless, WebConsole requires the data in this situation to be entered in the VVVV field as the system will not allow V N V N V N V N without a direction to be entered. Visibility of 10km or greater may be entered as Alternatively, the full visibility may be entered, eg, The advantage of doing this is that when retrieving an old message, the actual visibility observed will be displayed in the VVVV field. V N V N V N V N and Lowest direction Data entry: Complete these fields when reporting both a prevailing and minimum visibility in accordance with the flow diagram. Note: When applicable, the V N V N V N V N and direction boxes will not contain any data. 23

28 MetConsole Note: When MetConsole was conceived, the visibility coding requirements differed to that now in use. As a result, the entry of visibility data into MetConsole using the new requirements may not appear intuitive. Ensure the procedures outlined here are carefully followed. See Observations Instruction 13/05 for further explanations and visibility data entry examples. Visibility data is entered in accordance with the visibility flow diagram. Visibility is entered in metres after the appropriate rounding technique has been applied. When reporting the prevailing visibility only, enter this in the Vis1 (minimum) data field. When reporting a minimum visibility in rapidly fluctuating conditions, enter this in the Vis1 (minimum) field. When reporting both minimum (with direction) and prevailing visibility, enter these in the fields labelled as such. Note: Whenever a figure less than is entered in the Vis1 (minimum) field, the Vis1 Dir and Vis2 (prevailing) fields become active. Leave these fields blank unless in they are to be completed in accordance with the vis coding procedure (flow diagram). A37 Register of Weather Reports 0800mSE PREVAILING 09km 35km The column titled MAXIMUM is to be relabelled PREVAILING. Horizontal visibility is recorded on the A37 Register of Weather Reports in metres (four digits) up to and including 5000 metres, and in kilometres (two digits) above that value. The units of measurement (m or km) are also included. 24

29 Reporting and Recording Present Weather WebConsole Present 1, 2 & 3 Data entry: Present weather phenomena, at or near the local area and of significance to aeronautical operations. To report a present weather, the observer selects the phenomena from the Present Weather list (right) by clicking on the dotted button beside each present weather group. Alternatively, if the correct present weather code is known, it can be entered directly into the appropriate box using the keyboard. If no present weather phenomena are being reported, select NO SIG WX in the Present 1 box. The remaining boxes will auto-populate. A shortcut procedure for entering NO SIG WX is to type N into the data field and then press the Tab key. 25

30 MetConsole Up to three present weathers can be reported at each observation. If there are less than three present weathers to be reported the unnecessary data fields should indicate No Sig Wx. To report a present weather, the observer selects one of the options from the Present Weather drop-down list. Alternatively, if the correct present weather code is known, it can be entered directly into the appropriate box using the keyboard (in capital letters). A37 Register of Weather Reports +TSRA VCFC -RADZ In the event NO SIG WX is being reported when making the WebConsole entry, the Present Weather column of the A37 can be left blank. 26

31 Reporting and Recording Cloud WebConsole The rules for inclusion of clouds in an AWR are applied before making the WebConsole cloud entry. Cloud amount is entered as 1 to 8 (oktas). Cloud type can be selected from the dropdown list, or entered via the keyboard. Cloud height is entered in feet, rounded down to the nearest 100. In the event nil clouds are observed, all cloud layer fields are left blank. In the event the sky is obscured by fog, dustsorm, etc, / (forward slash) is entered in the 1 st layer amount box. See Observation Instruction 14/03 for further details. 27

32 The Cb or TCu not Previously Reported box is only used when Cb or TCu do not meet the rules for inclusion in the 1 st, 2 nd, or 3 rd layer boxes. In the example to the left, the CB that is observed meets the rule, therefore the Cb or TCu not Previously Reported box is not used. In the example to the left, the TCu does not meet the requirements of the rule, therefore it is reported as the 4 th layer. 28

33 MetConsole The rules for inclusion of clouds in an AWR are applied before making MetConsole cloud entry. Cloud amount is entered as 1 to 8 (oktas). Cloud type can be selected from the drop-down list, or entered via the keyboard. Cloud height is entered in feet, rounded down to the nearest 100. The Cb or TCu not previously reported box is only used when Cb or TCu do not meet the rules for inclusion in the 1 st, 2 nd, or 3 rd layer boxes. In the event nil clouds are observed, 0 (zero) is entered in the 1 st layer amount box. In the event the sky is obscured by fog, dustsorm, etc, leave the cloud entry boxes blank. See Observations Instruction 14/03 for further details. 29

34 A37 Register of Weather Reports Record those clouds on the A37 Register of Weather Reports as reported via WebConsole/MetConsole, noting the following points: If there are no clouds write SKC into the first cloud field. If the sky is obscured (not visible due to fog, dust, etc) write OBSC into the first cloud field. Enter the cloud height in hundreds of feet using three digits. For example 1,800ft is recorded as 018; 12,000ft is recorded as 120 Enter the cloud types from lowest to highest. Note: The terms CAVOK or NSC are not used on the A37 Register of Weather Reports even if the METARAWS/SPECIAWS has been encoded as such. 2 ST CU SC 060 SKC 30

35 Reporting and Recording Dry Bulb and Dew Point Temperatures WebConsole and MetConsole WebConsole and MetConsole automatically encodes the dry bulb and dew point temperatures into the METARAWS/SPECIAWS message using three digits to one decimal place (e.g for 7.1 degrees). No action is required from the observer aside from a QC check of the data. A37 Register of Weather Reports The Dry Bulb temperature and the Dew Point temperature are recorded on the A37 Register of Weather Reports using three digits to one decimal place M01.2 Values below zero are preceded by M. For example -7.1 C is recorded as M

36 Reporting and Recording QNH WebConsole and MetConsole WebConsole and MetConsole automatically encodes the QNH into the METARAWS/SPECIAWS message. It is reported as five digits to one decimal place. For example, a QNH of is coded as No action is required from the observer aside from a QC check of the data. A37 Register of Weather Reports The QNH is recorded on the A37 Register of Weather Reports to one decimal place The Climatological Practices Handbook does not indicate that a leading zero is required for values less than

37 Reporting and Recording Recent Weather WebConsole Up to three recent weathers can be reported at each observation. The appropriate phenomena can be selected from the drop-down list. If there are no reportable recent weather events, leave the data entry fields blank. 33

38 MetConsole MetConsole allows for up to three recent weathers to be reported at each observation. The appropriate recent weather can be selected from the drop-down list, or alternatively entered using the keyboard. If there are less than three recent weathers to be reported the unnecessary data fields should report No Sig Weather. A37 Register of Weather Reports RERA When recording recent weather on the A37, RE is used prior to the phenomena so as not to be confused with a present weather plain language remark. 34

39 Reporting and Recording Wind Shear WebConsole The wind shear data entry box appears on the lower left side of the METARAWS/SPECIAWS screen in the Plain Language Groups section. MetConsole The wind shear reporting box is accessed by clicking the More button on the MetarAWS screen. A37 Register of Weather Reports WS RWY09 35

40 Reporting and Recording Remarks WebConsole The rainfall group requires no action from the observer other than a QC check of the data. The plain language data entry box appears on the lower left side of the METARAWS/SPECIAWS screen in the Plain Language Groups section. The use of CAPITAL letters in this field will be consistent with the rest of the encoded message. The following text is not allowed in the Plain Language group: :, TTF, VER, NNNN, METAR, SPECI and ZCZC. 36