AWM

19 DEC 08
METEOROLOGY
© Jeppesen, 2006, 2008. All Rights
Reserved. Aerodrome Weather Report

AERODROME WEATHER REPORT – METAR AND SPECI DECODE

IDENTIFICATION GROUPS

METAR or METAR – Aviation routine weather report code name

SPECI SPECI – Aviation special weather report code name

COR COR – Code word used as appropriate

CCCC ICAO four-letter location indicator

YYGGgg In individual messages, day of the month and time of observation in hours and
minutes UTC

Z Indicator of UTC

NIL NIL – Code word used as appropriate

AUTO Fully automated observation indicator

SURFACE WIND

ddd Mean wind direction in degrees

true rounded off to nearest 10
degrees (VRB = VARIABLE when
ff < 3kt)

ff Mean wind speed (10-minute

00000 = calm
mean or since discontinuity) P199KMH (P99KT,
P49 MPS) mean ff or
G Indicator of Gust - if necessary fm fm = 200 KMH
(100 KT, 50 MPS) or
f m fm Maximum wind speed (gust) - if more
necessary

KMH or KT or MPS Wind speed units used

Followed when there is a variation in wind direction of 60° or more but less than 180° and wind speed > 3 KT by
group below:

d n dn dn Extreme direction of wind

V Indicator of Variability

d x dx dx Other extreme direction of wind (measured clockwise)

PREVAILING VISIBILITY

VVVV Prevailing visibility in metres or lowest visibility if visibility is not the same and
fluctuating and the prevailing visibility less than 5000m.

9999 = 10 km or more

Followed when visibility is not the same and minimum visibility is not prevailing and visibility < 1 500 m or visibility <
50% of prevailing and less than 5000m by the group below:

V n V n Vn Vn Lowest visibility

NDV Abbreviation for no directional variations.

Followed by

V n V n Vn Vn Lowest visibility

Dv General direction of lowest visibility or most operationally significant if minimum

visibility observed in more than one direction.

RUNWAY VISUAL RANGE (RVR) WHERE REQUIRED, UP TO FOUR ACTIVE RUNWAYS

R Indicator of RVR

DR DR Runway designator – for parallel runways may have LL, L, C, R or RR appended (L =

left; C = centre; R = right)

V R VR V R VR RVR (10-minute mean) at the touchdown zone P2000 = more than 2 000 m, M0050 =
less than 50 m

i RVR tendency indicator over past 10 minutes. U = upward; D = downward; N = no

distinct change. Omitted if possible to determine

Replaced when there are significant variations in RVR by the group below:
R Indicator of RVR

DR DR Runway designator – for parallel runways may have LL, L C, R or RR

V R VR V R VR RVR in metres (one-minute mean minimum value during last 10 minutes)

V Indicator of significant Variation

V R VR V R VR RVR in metres (one-minute mean maximum value during last 10 minutes)

i RVR tendency indicator

Note:

25 m STEP if RVR < 400 m

50 m STEP if 400 < RVR < 800 m

100 m STEP if RVR > 800 m

PRESENT WEATHER

w’w’ Present weather (see table w’w’ at the end of this sequence)

CLOUDS*

Ns Ns Ns Cloud amount:

FEW – FEW (1 – 2 oktas)

SCT – SCaTtered (3 – 4 oktas)

BKN – BroKeN (5 – 7 oktas)

OVC – OVerCast (8 oktas)

h s hs hs Height of base of clouds in units of 30 m (100 ft)

(CC) Cloud type – only CB (cumulonimubs) or TCU (towering cumulus) indicated or /// if it
cannot be observed by automatic system

Replaced when sky is obscured and information on vertical visibility is available by the group below:

VV Indicator of Vertical Visibility

h s hs hs Vertical visibility in units of 30 m (100 ft) /// = vertical visibility unavailable

Replaced when there are no such clouds, no restriction on vertical visibility and CAVOK is not appropriate by:

NSC Nil Significant Cloud

Replaced when automatic system is used and no cloud detected by:

NCD No Cloud Detected

* Clouds of operational significance (i.e. below 1 500 m (5000 ft) or below the highest minimum sector altitude,
whichever is greater, and CB or TCU)

CAVOK

Ceiling And Visibility OK. Replaces visibility RVR, present weather and cloud if:

(1) Visibility is 10 km or more

(2) No cumulonimbus, towering cumulus and no other cloud below 1 500 m (5 000 ft) or below the highest
minimum sector altitude, whichever is greater, and

(3) No significant present weather (see table w’w’ at the end of this sequence)

TEMP AND DEW POINT

T’T’ Temperature in whole degrees Celsius (if below 0°C preceded by M)

T’d T’d Dew-point temperature in whole degrees Celsius (if below 0°C preceded by M)

PRESSURE

Q Indicator of QNH in hectopascals. If Q = A then QNH is in inches

P H PH P H PH QNH rounded down to the whole nearest hectopascal or to tenths and hundreths of
an inch , depending on indicator

SUPPLEMENTARY INFORMATION

RECENT WEATHER

RE Indicator of REcent weather

w’w’ REcent weather since previous report (intensity NOT to be reported)

WIND SHEAR

WS Wind Shear

R RUNWAY

DR DR Runway designator – for parallel runways, may have LL, L, C, R or RR appended (L

= left; C = centre; R = right)

Replaced when all runways are affected by wind shear by: WS ALL RWY

STATE OF THE SEA / SURFACE TEMP

W Group indicator letter

Ts T s Temperature in whole degrees Celsius

S Indicator of state of the sea

S’ State of water surface

S’ STATE OF THE SEA

Code figure Descriptive terms

0 Calm (glassy)

1 Calm (rippled)

2 Smooth (wavelets)

3 Slight

4 Moderate

5 Rough

6 Very rough

7 High

8 Very high

9 Phenomenal

STATE OF THE RUNWAY **

RDR DR Indicator of runway

ER Runway deposits

CR Extent of runway contamination

e R eR Depth of deposit

B R BR Friction coefficient/breaking action

** State of the runway to be provided by appropriate airport authority

TREND FORECAST

TWO HOURS FROM TIME OF OBSERVATION

CHANGE INDICATORS

TTTTT or NOSIG BECMG BECoMinG, used where changes are expected to reach or pass
through specified values at a regular or irregular rate

TEMPO TEMPOrary fluctuations of less than one hour and in aggregate less
than half the period indicated by GGGe Ge

NOSIG NO SIGNIFICANT CHANGE

CHANGE AND TIME

TT Can be AT or FM = FROM or TL = TILL

GGgg Associated time group in hours and minutes UTC

FORECAST WIND

ddd Forecast mean wind direction in degrees true, rounded

to nearest 10 degrees (VRB = VARIABLE)

ff Forecast mean wind speed

00000 = calm
G Indicator of Gust

f m fm Forecast maximum wind speed (gust)

KMH or KT or MPS Wind speed units

FORECAST VISIBILITY
VVVV Forecast prevailing visibility in metres 9999 = 10 km or more

FORECAST WEATHER

w’w’ Forecast significant weather (see table w’w’ at the edn of this sequence)

Replaced when significant weather ends by:

NSW Nil Significant Weather

FORECAST CLOUDS OF OPERATIONAL SIGNIFICANCE OR VERTICAL VISIBILITY

Ns Ns Ns Forecast cloud amount

h s hs hs Forecast height of base of cloud

(CC) Cloud type - only CB

Replaced when sky expected to be obscured and vertical visibility forecasts are undertaken by:

VV Indicator of Vertical Visibility

h s hs hs Vertical visibility in units of 30 m (100 ft)

Replaced when no cumulonimbus, towering cumulus and no other cloud below 1 500 m (5 000 ft) or highest
minimum sector altitude, whichever is greater, are forecast and CAVOK is not appropriate by:

NSC Nil Significant Cloud

RMK

Information included by national decision but not disseminated internationally

w’w’ SIGNIFICANT PRESENT, FORECAST AND RECENT WEATHER

QUALIFIER WEATHER PHENOMENA

Intensity of
Proximity Descriptor Precipitation Obscuration Other

1 2 3 4 5

– Light MI Shallow DZ Drizzle BR Mist PO Dust/sand

Moderate (no whirls (dust
BC Patches RA Rain FG Fog
qualifier) devils)
+ Heavy or PR Partial SN Snow FU Smoke SQ Squalls
well-developed (covering part
SG Snow grains VA Volcanic FC Funnel
in the case of of the
ash cloud(s)
PO and FC aerodrome) DU
(tornado or
Widespread
waterspout)
dust

VC In the vicinity DR Low drifting IC Ice crystals SA Sand SS Sandstorm

(diamond
BL Blowing HZ Haze DS Duststorm
dust)

SH Shower(s) PL Ice pellets

TS Thunderstorm GR Hail

FZ Freezing GS Small hail

(supercooled) and/or snow
pellets

UP Unknown
Precipitation

NOTES: 1. The w’w’ groups are constructed by considering columns 1 to 5 in the table above in sequence,
that is intensity, followed by description, followed by weather phenomena. An example could be:
+ SHRA (heavy shower(s) of rain).

2. First precipitation type listed is the predominate precipitation type. Any second or third
precipitation type has no intensity qualifier and is of equal or of less intensity than the first
precipitation type.

3. DR (low drifting) less than two metres above ground, BL (blowing) two metres or more above
ground.

4. GR is used when hailstone diameter is 5 mm or more. When less than 5 mm, GS is used.

5. BR – visibility at least 1 000 m but not more than 5 000 m. FG – visibility less than 1 000 m.

6. VC – between approximately 8 km and 16 km from the aerodrome reference point.