Lesson 22 - Meteorological Info Flashcards
Where are the two World Area Forecast Centres?
London and Washington
What info will meteorological offices issue?
Terminal Area Forecast
- TAF (Rumour)
What info will meteorological stations issue?
METAR (Truth)
Name the three warnings that meteorological watch offices might issue
SIGMET
AIRMET
ASHTAM
VAAC stands for what?
Volcanic Ash Advisory Centres
TCAC stands for what?
Tropical Cyclone Advisory Centres
World Area Forecast Centres provide what type of forecast?
Upper-air gridded forecast
How often do WAFCs issue significant weather charts?
6-9 hours
Meteorological Offices issue TAFs how often and how long are they valid for?
3 or 6 hours
Valid between 6-30hours
How often is a METAR produced?
30 or 60mins
What is a SPECI
interim METAR due to significant change
What is a TREND?
Mini forecast valid for 2 hours. Also known as LANDING FORECAST
What is a SNOWTAM?
Warning of airfield condition due to snow/slush/ice valid for up to 8 hours
What is an AERODROME WARNING (ADW)?
Warning of conditions affecting aircraft such as vehicles, debris and facilities on ground etc.
What is a SIGMET?
Significant level of change in the upper level valid for 4-6 hours, produced by met watch office (MWO). 4hours generally, 6 only if volcanic or cyclone activity also present.
SIGnificant METeorological change
What is an AIRMET?
Report of weather produced by pilots at low level FL100/150 valid for 4 hours
What is an ASHTAM?
Report of volcanic activity & ash clouds valid up to 24h
What conditions will a SIGMET report on?
Thunderstorms (TS)
Tropical Cyclone (TC with +34kt crosswinds)
Severe Turbulence
Severe Icing (inc SEV due FZRA)
Severe Mountain Waves
Heavy Sand or Dust storm (SS, DS)
Volcanic Ash (VA)
Radioactive Cloud (RDOACT)
Who is responsible for issuing a SIGMET?
Meteorological Watch Office (MWO)
What does a TREND do?
Supersedes any current TAF for 2 hours, known as landing forecast. Found at end of METAR or SPECI (TEMPO)
What conditions must exist for a CAVOK to be issued?
No cloud below 5000ft or 1000ft above highest obstacle MSA (minimum safe altitude), whichever is greater
Visibility 10km or more
No CB or TCU at any height
No significant weather phenomena eg blowing snow, tornadoes etc.
What is a jet stream?
Bands of strong winds that generally blow from east to west and are found at the top of the troposphere
When the maximum speed of a jet stream core is in excess of 120kt additional information indicating the flight levels between which the wind is equal to or in excess of ____ is given
80kt
If there is insufficient space on the jet stream to display a full wind symbol, a change bar is (—//—) used whenever the jet stream changes by_____
+/-20kt or +/-3000ft
What is the okta scale for clouds (except CB)?
FEW - 1/8 to 2/8
SCT - 3/8 to 5/8
BKN - 5/8 to 7/8
OVC - 8/8
Winds reported by the control tower and in ATIS reports are averaged over the previous how many minutes?
30 min
Surface wind measurements contained in METAR and SPECI reports are averaged over the previous how many minutes?
10 mins
The ATS unit gives instantaneously winds at airports used by traffic with a MTOM greater than how many kg?
5700kg
