Mnemonics & Main Memory Items | Meteorology

Question 1

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

Answer 1

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

Question 2

Poles: Height 8km; Temp -

Mid-latitudes: Height 11km; Temp -

Equator: 16km; Temp -

Answer 2

Poles: Height 8km; Temp -50 °C

Mid-latitudes: Height 11km; Temp -56 °C

Equator: 16km; Temp -75 °C

Question 3

The SALR and DALR in degrees per meter is -

Answer 3

SALR - 0.6/100m

DALR - 1/100m

Question 4

In the both hemispheres gradient wind is added to geostrophic wind around a -

And subtracted -

Answer 4

Anti-cyclone

Low pressure system

Question 5

The mnemonic for wind shear operation effect:

Answer 5

Reduction(DUO) - working from right to left:

Under.
Over

Increase(IOU) - working from right to left:

Over
Under

Question 6

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 ____

Answer 6

• 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

Question 7

CAVOK criteria(4):

Answer 7

• 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.

Question 8

Pressure Levels:

Answer 8

FL050= 850 hPa
FL10= 700 hPa
FL180= 500 hPa
FL300= 300 hPa

Question 9

High(pressure) to low(pressure) -

Hot to cold -

Answer 9

Look down below(Altimeter overreads)

Don’t be bold(altimeter overreads)

Question 10

the definition of relative humidity?

Answer 10

Ratio between the actual mixing ratio and the saturation mixing ratio multiplied by 100

Question 11

Veering =

Backing =

Answer 11

Clockwise

anti-clockwise.

Question 12

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?

Answer 12

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

Question 13

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?

Answer 13

20 min

20/30 min

air mass thunderstorms

The sides

Question 14

fronts:

With the passage of a cold front the wind will(SH and NH):

Answer 14

Back in the SH and veer in the NH

Question 15

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?

Answer 15

Stated in the TAF

feet

When gusts are at least 10 knots above the mean wind speed

2 hours

Question 16

Does the coriolis force deflect to the right in both hemispheres?

Answer 16

No! it does not. Check with a paper on pen

Question 17

Significant Changes that need to be transmitted:

· Mean head wind component

· Mean crosswind component

· Mean tail wind component

Answer 17

· 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)

Question 18

Coriolis force increases -

For a constant PGF, wind speed will at high latitudes will be -

Answer 18

Towards the poles

Less than at lower latitudes

Question 19

The stratosphere:

Extends to -

The lapse rate?

Answer 19

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.

Question 20

The troposphere:

Extends to(polar, tropical and 45 degree latitudes):

The lapse rate?

The pressure decrease rate?

Answer 20

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.

Question 21

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?

Answer 21

Positions with the same air pressure at a given level
reduced to sea level
QFF(true altitude)
true heights AMSL
An isohypse (contour)

Question 22

Mnemonic to remember ridge and trough?

Answer 22

Ridge is relevant to high pressure(ridges of a mountain is high)

Trough is the opposite, being related to low pressure.

Question 23

True altitude corrects -

Answer 23

Indicated altitude for temperature error