awp metarspeci

7/29/2019 Awp Metarspeci

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METAR/SPECI

A METAR is a routine report o meteorological conditions at an aerodrome.

A SPECI is a special report o meteorological conditions, issued when one or more

elements meet specifed criteria signifcant to aviation. SPECI is also used to identiy

reports o observations recorded ten minutes ollowing an improvement (in visibility,

weather or cloud) to above SPECI conditions.

Location

The location is indicated by either the ICAO (International Civil Aviation Organization)

location indicator or another approved abbreviation.

Date/Time

The day o month and the time o the report is given in UTC (Coordinated Universal

Time) using six fgures ollowed by the letter Z. The frst two digits are the day o the

month; the ollowing 4 digits are the time in hours and minutes, e.g. 291741Z (time oreport is 1741 on the 29th o the month UTC).

AUTO

The abbreviation AUTO will be included when the report contains only automated

observations.

Surface Wind

The wind direction is given in degrees true, rounded to the nearest 10 degrees. A

variable wind direction is given as VRB.

The wind speed, given in knots (KT), is the mean value over the sampling period which

is normally ten minutes. The maximum wind speed during the sampling period is

reported when it exceeds the mean speed by 10 knots or more. It is indicated by the

letter G which is ollowed by the gust value, e.g. a wind direction o 280, with a meanspeed o 20 knots and a maximum gust o 31 knots, is given as 28020G31KT.

At selected aerodromes, an additional wind variation feld may also be included when

the wind direction varies by 60 degrees or more in a ten minute period. It lies ater the

main wind group and shows the range o observed wind directions e.g. 360V090.

Visibility

The horizontal visibility is given in metres up to 9000 metres; with 9999 being used to

indicate a visibility o 10 kilometres or greater.

When the visibility is estimated manually (i.e. by an observer), two groups may be

reported when the visibility is not the same in dierent directions. In these cases, the

higher visibility will be given frst, ollowed by the minimum visibility and its direction

(using one o the eight points o the compass) rom the observing station e.g. 90002000N.

When visibility is given by an automated sensor (in ully AUTOmated reports), only one

group will be reported, and any variation in visibility that may exist will not be given.

AVIATION WEATHER PRODUCTS

METAR/SPECI

Bureau o Meteorology Weather Services Aviation

METAR YPPH 221130Z

28012KT 8000 -RA FEW005

OVC110 27/22 Q0999 RERA

RMK RF00.6/003.4

SPECI YSCB 171515Z AUTO

22015G25KT 9000NDV //

NCD 13/09 Q1003 RMK

RF00.8/003.0

Indicates elements which mayor may not be included

Date/

TimeAUTO Wind

TEMP/

DEW PT

Supplementary

InormationRemarksQNH

RVR CloudVIS WX

METAR or

SPECILocation

CAVOK


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Runway Visual Range (RVR)

RVR will be reported rom aerodromes with RVR instrumentation whenever the RVR

or the visibility are less than 1500 metres. It will be reported in the ormat RDD[n]/[n1]

V1V

1V

1V

1[V n

2V

2V

2V

2V

2]i (the elements in brackets are included only when applicable).

CODE DESCRIPTION

R A fxed indicator, denoting that RVR inormation ollows

DD Designates runway threshold or which RVR is being reported

n Parallel runways will be distinguished by the letter L, C or R indicating the

let, centre or right runway, respectively

/ A fxed separator

n1

n1will be given as P when either the RVR is either greater than the

maximum value which can be assessed by the system (in which case

VVVV will report this value), or when the RVR is greater than 2000 metres

(in which case VVVV will be reported as 2000)

V1V

1V

1V

1 Gives the last 10-minute average RVR value except when the RVR has varied

signifcantly during the sampling period, in which case it gives the minimum

one-minute average value during this period (and is ollowed by V V2V

2V

2V

2).

V A fxed indicator, included only when RVR has varied signifcantly during

the sampling period.

n2

n2will be given as M when either the RVR is either less than the minimum

value which can be assessed by the system (in which case VVVV will

report this value); or when the RVR is less than 50 metres (in which case

VVVV will be reported as 0050).

V2V

2V

2V

2 Gives the maximum one-minute average value during the sampling period.

Is only included when the RVR has varied signifcantly during this period.

i Gives any distinct tendency o the RVR over the sampling period eitherU (upward), D (downward) or N (nil).

Weather

Weather phenomena are reported using the codes listed in the table on the let.

Intensity is indicated or precipitation, duststorms, sandstorms and unnel clouds by

appending:

theprex-forlight,e.g.-DZ

theprex+forheavy,e.g.+RA

noprexformoderate,e.g.SHRA

When precipitation is reported with TS, the intensity indicator reers to theprecipitation, e.g. -TSRA = thunderstorm with light rain.

Oneormorecodesmaybegrouped,e.g.+TSGR,-TSRASN

An observation may provide an indication o weather in the vicinity o the aerodrome,

i.e. between 8 and 16KM o the aerodrome reerence point. In these cases, the

weather code is prefxed with the abbreviation VC (vicinity), e.g. VCTS.

Cloud

Cloud inormation is reported rom the lowest to the highest layers in accordance with

the ollowing rules:

1stgroup:thelowestlayerregardlessofamount.

2ndgroup:thenextlayercoveringmorethan2oktasofthesky.

3rdgroup:thenexthigherlayercoveringmorethan4oktasofthesky.

Extragroups:forcumulonimbusand/ortoweringcumulusclouds,whenever

observed and not reported in any o the above.

Cloud amount is described using the codes in the table on the let.

Code Weather Descriptor

MI shallow

BC patches

PR partial

DR driting

BL blowing

SH showers

FZ reezing

TS thunderstorm

Code WeatherPhenomena

DZ drizzle

RA rain

GR hail

SN snow

SG snow grains

DU dust

SA sand

SS sandstorm

DS duststorm

GS small hail/snow pellets

PL ice pellets

FG og

BR mist

FU smoke

HZ haze

PO dust devil

SQ squall

FC unnel cloud

VA volcanic ash

IC ice crystals


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Code Cloud Amount

FEW ew (1 to 2 oktas)

SCT scattered (3 to 4 oktas)

BKN broken (5 to 7 oktas)

OVC overcast (8 oktas)

NSC nil signifcant cloud

NCD* nil cloud detected

Cloud height is given as a three-fgure group in hundreds o eet above the aerodrome

elevation, e.g. cloud at 700 eet is shown as 007.

Cloud type is identifed only or cumulonimbus and towering cumulus, e.g.

FEW030CB, SCT045TCU.

When an individual layer is composed o cumulonimbus and towering cumulus with acommon base, the cloud is reported as CB only.

I the sky is obscured due to, or example, bushfre smoke, human observers will

report the vertical visibility (when it can be estimated) in lieu o cloud. It is reported

with the prefx VV ollowed by the vertical visibility in hundreds o eet, e.g. the group

VV003 reports an estimated vertical visibility o between 300 and 399 eet (values are

rounded down to the next hundred oot increment).

CAVOK

The abbreviation CAVOK (Cloud and Visibility OK) is used when the ollowing

conditions are observed simultaneously:

Visibilityis10kilometresormore;

Nocloudbelow5000feetorbelowthehighest25NMminimumsectoraltitude,which-ever is the higher, and no cumulonimbus and no towering cumulus; and

Noweatherofsignicancetoaviation,i.e.noneoftheweatherphenomenalistedin

the weather table.

Temperature

Air temperature and dew point values are rounded to the nearest whole degree.

Negative values are indicated by M (minus) beore the numeral, e.g. 34/M04

Pressure (QNH)

TheQNHvalueisroundeddowntothenextwholehectopascalandisgivenusingfour

fgures prefxed by Q, e.g. 999.9 is given as Q0999

Supplementary InformationSupplementary inormation is used to report:

RecentWeathersignicantweatherobservedsincethelastreportbutnotatthe

time o observation is given ater the prefx RE, e.g. RERA.

WindShearreportsofwindshearexperiencedontake-offorlandingaregiven

ater the indicator WS, e.g. WS R16.

Remarks

The Remarks section (indicated by RMK) may contain the ollowing:

QuantitativeinformationonpastrainfallisgiveninmillimetersintheformRFRR.R/

RRR.R or RFRR.R/RRR.R/RRR.R. The ormer, e.g. RF00.2/004.2, gives the

rainall recorded in the ten minutes prior to the observation time, ollowed by

the rainall recorded in the period since 0900 local time. The second ormat, e.g.

RF00.2/003.0/004.2, gives the rainall recorded in the ten minutes prior to the

observation, ollowed by the rainall in the sixty minutes prior to the observation,

ollowed by the rainall recorded in the period since 0900 local time.

Informationofoperationalsignicancenotreportedinthebodyofthemessage,for

example:

inormation about signifcant conditions (such as bushfres and distant

thunderstorms) beyond the immediate vicinity o the aerodrome,

any BKN or OVC low or middle cloud present at or above 5000 eet when CAVOK

has been included in the body o the message,

CLD:SKY MAY BE OBSC may be reported in ully automated reports when the

ceilometer (cloud sensor) detects nil cloud and the visibility sensor estimates

horizontal visibility as being less than 1000 metres

Data Not Available

Where a data group is not available, solidi will be reported in lieu o the missing group,

e.g. //// or visibi lity, // or weather and ////// or cloud.

* NCD is reported (in fully automatedreports only) when a cloud sensor

detects nil cloud.


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Airservices Australia is the ofcial distributor of aviation forecasts, warnings and observations

issued by the Bureau of Meteorology. Airservices ight brieng services are available atwww.airservicesaustralia.com. Telephone contact details for elaborative briengs are containedin Airservices Aeronautical Information Publication Australia (AIP), which is available onlinethrough their website.

Other brochures produced by the Bureau of Meteorologys aviation weather services program

can be found at www.bom.gov.au/aviation/knowledge-centre.

Commonwealth of Australia, 20 December 2012

* Where no descent procedure is established for an aerodrome, the aerodromes alternate ceiling

and visibility are 1500 feet and 8 kilometres respectively.

METAR/SPECI Example

SPECIYMML221945Z14004KT0600R16/0600DR27/0550NFGVV///08/08

Q1026RMKRF000.0/001.8

REPORT EXPLANATION

SPECI Special meteorological observation (or wind gust)

YMML ICAO location indicator or Melbourne Airport

221945 Time o observation is 1945 on the 22nd o the month UTC

14004KT Wind is rom the southeast (140 degrees True) at 4 knots

0600 Visibility is 600 metres

R16/0600D Runway visual range on runway 16 threshold is 600 metres, and is

trending down

R27/0550N Runway visual range on runway 27 threshold is 550 metres,with niltrend

FG Present weather is og

VV/// The sky is obscured (by og); the vertical visibility is unknown

08/08 The air temperature and the dewpoint temperature are both 8C

Q1026 TheQNHisbetween1026and1026.9hectopascals

RMK Remarks section ollows

RF00.0/001.8 There has been nil rain in the last 10 minutes; 1.8 mm has allen since

0900 local time

SPECI Criteria

SPECI is used to identiy

reports o observations

when conditions are

below specifed levels o

visibility and cloud base;

when certain weather

phenomena are present;

and when temperature,

pressure or wind change

by defned amounts

(outlined in the table on

the right).

SPECI is also used

to identiy reports o

observations recorded10 minutes ollowing an

improvement in visibility,

weather or cloud to

METAR conditions.

Element Criterion

Wind Direction Changes o 30 or more, the mean speed beore or ater the change

being 20KT or more

Wind Speed Changes o 10KT or more, the mean speed beore or ater the change

being 30KT or more

Wind Gust Gusts of 10KT or more above a mean speed of 15KT or more

Gust exceeds the last reported gust by 10KT or more

Visibility When the horizontal visibility is below the aerodromes highest

alternate minimum visibility*

Weather When any o the ollowing begins, ends, changes in intensity, or is

occuring at a routine reporting time:

thunderstorm

hailstorm

mixed snow and rain

freezing precipitation

drifting snow

squall

fog (including shallow fog, fog

patches and og at a distance)

dust storm

sandstorm

funnel cloud

moderate or heavy precipitation

Cloud When there is BKN or OVC cloud below the aerodromes highestalternate minimum cloud base*

Temperature When the temperature changes by 5C or more since last report

Pressure When the QNH changes by 2hPa or more since last report

Other Upon receipt of advice of the existence of wind shear

The incidence of any other phenomenon likely to be signicant
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