Meteorology Flashcards
Def: Ceiling
Also for which approaches do you apply ceiling?
The height above the ground of the base of the lowest layer of cloud below 20 000ft covering more than half the sky.
Use only vis/RVR for Precision approaches.
Plus ceiling for Non-precision approaches
Unless the specific state requires the use of ceiling and then it would be indicated in LIDO
Nosig
No significant changes forecast or no cessation of weather given in the preceding part of TAF or reported in METAR.
This is a trend Forecast - 2 Hours from the Time of Observation
CAVOK
- Vis 10km or more
- No cloud of operational significance
(no cloud with a base below 5000ft or below the highest
MSA or CB or TCB at any height) - No weather of significance to aviation
NSC (No Significant Cloud)
No Cloud of Operational Significance (Cloud base not below 5000 feet or MSA and no CB or TCU any height)
CAVOK not appropriate
Cloud Base
The height of the base of the lowest observed or forecast cloud element in the vicinity of an aerodrome
Tempo
Tempo fluctuations lasting less than 1 hour and in aggregate not more than half of the period.
Use FM and TL unless the TEMPO occurs wholly within the TAF
Shower
Precipitation from a cumuliform cloud; characterized by the suddenness of beginning and ending, by the rapid change of intensity, and usually by rapid change in the appearance of the sky; showerly precipitation may be in the form of rain, ice pellets or snow
RVR P2000: P?
More than
RVR 1200U/D/N: U D N?
U- upward
D- downward
N- no tendancy
TAF, Def, how long can it be?
Terminal Area Forecast.
6h to 30h
BECMG def plus how is the time indicated?
BECMG is used in TAFs to describe forecast changes. FM, TL, AT to be used.
FM- the change would continue after the end of the TAF
TL- it would end within the TAF
AT- time start and finish in the TAF
When the time is uncertain only BECMG should be used
CB
Cumulonimbus cloud
One danger of flying above the tropopause
Ice Crystal Icing- when cloud tops are above the tropopause
RE
Recent weather phenomena observed during the period
since the last issued routine report or last hour, whicheveris the shorter, but not at the time of observation
FOG and MIST
FOG: vis less than 1000m
MIST: vis 1000m or more but not more than 5000m