With reference to cloud amount, explain the meaning of:
a) SKC;
b) NSC;
c) FEW;
d) SCT;
e) BKN;
f) OVC;
g) CAVOK.
a) SKC – Sky Clear
b) NSC – No Significant Cloud
c) FEW – 1-2 oktas
d) SCT – 3-4 oktas
e) BKN – 5-7 oktas
f) OVC – 8 oktas
g) CAVOK – “Ceiling and Visibility are okay”
– This is used when the visibility is 10 km or more,
– there is no cloud below 5000ft – (or below the minimum sector altitude [ IFR] )
– no CB or TCU (cumulonimbus and towering cumulus without anvil respectively)
– no precipitation and no thunderstorms
* One okta is 1/8th of the sky covered , ie 4 oktas is about half the sky cloud covered and 8 oktas is completely overcast
Include PIREPS and AIREPS, these are an important part of the weather system
– good feedback from pilots provides better information for other pilots
– all pilot reports are passed back to Metservice and if severe weather was encountered there may be a SIGMET issued
– any information is good and able to be put to use
Basic Weather Reports
– Verbal weather reports passed to pilots from non-certified observers near an airfield or other place such as a mountain pass
– If provided through UNICOM or ATS operator the report can be relied upon as it is accurate
Aerodrome and Weather Information Services
Operated in a similar manner to ATIS – except they are non-certified and the information transmitted is recorded automatically
AWIB are advisory only – should not be relied upon as information may be coming from multiple non-certified private sources
Weather (MET) Card August 2017
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ATIS
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The ATIS is a continuous
plain language broadcast of the current conditions at an aerodrome, on a
discrete frequency.
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Issue times
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Irregularly, when
conditions change or deteriorate
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Heights
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Feet above aerodrome
level
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Wind
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Speed
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Knots
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Direction
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Degrees magnetic
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Visibility
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Less than 5000 metres –
in metres, eg 3000
5000 metres or more – in
kilometres, eg 5KM
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Cloud
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Type
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CB, TCU
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Amount
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SKC, FEW, SCT, BKN, OVC
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Temperature/ Dew Point
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Degrees Celsius
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Pressure (QNH for ATIS only)
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Hectopascals (hPa)
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Weather (MET) Card August 2017
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SIGMET
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SIGMETs provide
information on observed or forecast hazardous weather conditions.
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Issue times
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As required
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Validity
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Four hours (six hours
for volcanic ash and tropical cyclones), reviewed after three hours or when
further information available
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Heights
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Feet above mean sea
level up to 10,000 feet, flight levels from FL 100
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Area
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New Zealand FIR (NZZC)
and Auckland Oceanic FIR (NZZO)
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Weather (MET) Card August 2017
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METAR, METAR AUTO and SPECI
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A METAR is a routine
meteorological report, compiled manually, provided for a specific aerodrome,
and presented in code.
A METAR AUTO is a
routine meteorological report provided by an automatic weather station (AWS)
for a specific aerodrome, also presented in code.
A SPECI is a METAR
issued outside of the routine issue time of a METAR (NZWP, NZOH and NZMF
only).
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Issue times
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METARs issued hourly, on
the hour
METAR AUTOs issued every
half hour, 24 hours a day
SPECIs issued when
required and will have issue time other than on the hour SPECIs not issued at
Metar Auto aerodrome
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Heights
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Feet above aerodrome
level
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Area
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Within 8 km of the
aerodrome reference point
When the term VC is used
this applies to the area between 8 and 16 km from the aerodrome reference
point
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Wind
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Speed
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Knots
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Direction
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Degrees true. When
direction varies by 60 degrees or more, the extreme directions are given,
separated by the letter V, e.g. 260V330
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Visibility
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Up to 9999 metres – in
metres, eg 7000
Above 9999 metres – in
kilometres, eg 20KM
Visibility variation
shown by adding the direction, eg 2000SW – visibility variation not reported
in METAR AUTO
CAVOK and 9999 (10 KM or
more) used at Auckland, Wellington and Christchurch only
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Cloud
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Type
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CB, TCU
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Amount
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NSC, SKC, FEW, SCT, BKN,
OVC
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Temperature/ Dew Point
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Degrees Celsius
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Pressure (QNH)
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Hectopascals (hPa)
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Weather (MET) Card August 2017
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TAF and TREND
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A TAF is an aerodrome
forecast provided for a specific aerodrome presented in code.
A TREND is a forecast,
valid for two hours, attached to the end of a METAR or SPECI (NZWP, NZOH
only) and METAR AUTO (NZAA, NZWN, NZCH only), stating any significant changes
from those described. While the TREND is valid it supersedes the aerodrome
TAF.
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Issue times
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NZAA, NZWN and NZCH:
2300, 0500, 1100, and 1700 UTC
All other aerodromes:
0230-0430, 0930-1015, and 1400-1445 local time
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Validity
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1921/2012 = valid from
2100 UTC on the 19th to 1200 UTC on the 20th
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Heights
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Feet above aerodrome
level
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Area
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Within 8 km of the
aerodrome reference point
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Wind
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Speed
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Knots
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Direction
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Degrees true
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Visibility
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Up to 9999 metres – in
metres, eg 7000
Above 9999 metres – in
kilometres, eg 20KM
CAVOK and 9999 used at
Auckland, Wellington and Christchurch only
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Cloud
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Type
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CB, TCU
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Amount
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NSC, SKC, FEW, SCT, BKN,
OVC
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Weather (MET) Card August 2017
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ARFOR
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Area forecasts are
forecasts for a specific region. They are intended for domestic VFR and IFR
flights below 10,000 feet. The 17 ARFOR areas are designated by two-letter
codes.
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Issue times
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0530-0610 and 1130-1210
local time
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Heights
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Feet above mean sea
level
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Area
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Within the named area,
eg TA (Tamaki)
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Wind
|
Speed
|
Knots
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|
Direction
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Degrees true
|
|
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Visibility
|
Up to 9999 metres – in
metres, eg 7000
Above 9999 metres – in
kilometres, eg 20KM
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Cloud
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Type
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AS, AC, NS, SC, ST, TCU,
CB
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Amount
|
SKC, FEW, SCT, BKN, OVC
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Temperature
|
Degrees Celsius
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