Mnemonics & Main Memory Items | Meteorology Flashcards
As altitude increases, the air becomes less dense. Therefore the change in feet per hPa will increase.
You only need to know the values below for the exam:
1hPa = \_\_ft at sl 1hPa = \_\_ft at 10,000ft 1hPa = \_\_ft at 18000ft
As altitude increases, the air becomes less dense. Therefore the change in feet per hPa will increase.
You only need to know the values below for the exam:
1hPa = 27ft at sl
1hPa = 36ft at 10,000ft
1hPa = 50ft at 18000ft
Poles: Height 8km; Temp -
Mid-latitudes: Height 11km; Temp -
Equator: 16km; Temp -
Poles: Height 8km; Temp -50 °C
Mid-latitudes: Height 11km; Temp -56 °C
Equator: 16km; Temp -75 °C
The SALR and DALR in degrees per meter is -
SALR - 0.6/100m
DALR - 1/100m
In the both hemispheres gradient wind is added to geostrophic wind around a -
And subtracted -
Anti-cyclone
Low pressure system
The mnemonic for wind shear operation effect:
Reduction(DUO) - working from right to left:
Under.
Over
Increase(IOU) - working from right to left:
Over
Under
mountain waves may also be referred to as standing waves or lee waves. These occur when the following conditions exist:
- The wind direction is perpendicular to the mountain range (+/-30°) without significant change in direction as altitude increases
- The wind speed at the summits is at least __ kt with speed increasing as altitude increases
- A marked layer of _____ around the altitude of the ______, e.g. an _______ layer or ______, with less ____ air ____ and ____
- The wind direction is perpendicular to the mountain range (+/-30°) without significant change in direction as altitude increases
- The wind speed at the summits is at least 15 kt with speed increasing as altitude increases
- A marked layer of stability around the altitude of the summits, e.g. an isothermal layer or inversion, with less stable air above and below
CAVOK criteria(4):
- the visibility must be 10 kilometres or more.
- the height of the lowest cloud must be no less than 5000 ft, or the level of highest minimum sector altitude, whichever is the greater.
- there must be no cumulonimbus or ‘towering cumulus’ (TCU) present.
- there must be no significant weather at or in the vicinity of the aerodrome.
Pressure Levels:
FL050= 850 hPa FL10= 700 hPa FL180= 500 hPa FL300= 300 hPa
High(pressure) to low(pressure) -
Hot to cold -
Look down below(Altimeter overreads)
Don’t be bold(altimeter overreads)
the definition of relative humidity?
Ratio between the actual mixing ratio and the saturation mixing ratio multiplied by 100
Veering =
Backing =
Clockwise
anti-clockwise.
Jet Streams:
tropical Jet Stream time of the year and altitude?
Which jet stream is associated with a surface front system?
What is the approximate ratio between height and width for a jet stream cross section?
In which zone of a jet stream is the strongest CAT to be expected?
The minimum speed for winds to be classified as a jet stream?
Where, as a general rule, is the core of the polar front jet stream to be found?
Which of the following types of jet streams can be observed all year round?
June to august, FL500
Polar front jet stream
1/1000
Cold side of the jet stream core
60kts
Warm air mass
Sub-tropical jet stream/polar front jet stream
Thunderstorms:
The building stage of a thunderstorm last for approximately?
The mature stage of a thunderstorms lasts for approximately?
Which thunderstorms are the more difficult to forecast and detect?
If you cannot avoid penetrating a thunderstorm, which is the best area to penetrate?
20 min
20/30 min
air mass thunderstorms
The sides
fronts:
With the passage of a cold front the wind will(SH and NH):
Back in the SH and veer in the NH
TAF and METAR:
The validity of a TAF is?
Vertical visibility is given in meters or feet?
When will the surface wind in a METAR record a gust factor?
How long from the time of observation is a TREND in a METAR valid?
Stated in the TAF
feet
When gusts are at least 10 knots above the mean wind speed
2 hours
Does the coriolis force deflect to the right in both hemispheres?
No! it does not. Check with a paper on pen
Significant Changes that need to be transmitted:
· Mean head wind component
· Mean crosswind component
· Mean tail wind component
· Mean head wind component 19 km/h (10 kt)
· Mean crosswind component 9 km/h (5 kt)
· Mean tail wind component 4 km/h (2 kt)
Coriolis force increases -
For a constant PGF, wind speed will at high latitudes will be -
Towards the poles
Less than at lower latitudes
The stratosphere:
Extends to -
The lapse rate?
From the earth’s surface to 50km.
The temperature remains constant from troposphere average 11km at -56.5 celsius up to 20km. From 20km to 32km the temperature increases by 0.3 celsius / 1 000ft up to a peak of 0 at 50km. The temperature starts to increase due to the ozone layer which absorbs intense solar radiation.
The troposphere:
Extends to(polar, tropical and 45 degree latitudes):
The lapse rate?
The pressure decrease rate?
8 km above cold polar areas and;
16 km above warm tropical regions
At the 45 degree latitudes the average height is 11km
1.98 celsius per 1 000ft up to a height of 11km(tropopause average), thereafter the temperature remains constant at -56.5 celsius.
Pressure decreases at an average rate of 1 hPa per 27 feet. This pressure decrease is not constant and reduces with altitude, approximately 1 hPa per 47 feet at 20 000ft.
What positions are connected by isobars on the surface weather chart?
The isobars drawn on a surface weather chart represent lines of equal pressure?
The station pressure used in surface weather charts is?
Contour heights are?
Positions with the same air pressure at a given level reduced to sea level QFF(true altitude) true heights AMSL An isohypse (contour)
Mnemonic to remember ridge and trough?
Ridge is relevant to high pressure(ridges of a mountain is high)
Trough is the opposite, being related to low pressure.
True altitude corrects -
Indicated altitude for temperature error
