Synoptic Charts/Weather

Question 1

Define isobar

Answer 1

Join places of equal atmospheric pressure

Question 2

What are isobars measured in

Answer 2

Hectopascals (hPa)- often 2hPa intervals

Question 3

What is another term for atmospheric pressure?

Answer 3

Barometric pressure

Question 4

Define atmospheric pressure

Answer 4

The weight of air pressing down on Earth’s surface.

Question 5

Anticyclones is another term for

Answer 5

High Pressure systems

Question 6

T or F- high pressure systems are cool air descending

Answer 6

true

Question 7

Characteristics of high pressure systems

Answer 7

Stable atmospheric conditions- gentle wind, clear skies, low rain.

Question 8

T or F- air pressure increases towards centre of High pressure systems

Answer 8

true

Question 9

What direction does air flow out of high pressure systems in southern hemisphere?

Answer 9

Anticlockwise outwards from centre

Question 10

What type of pressure system dominates southern Aus in summer?

Answer 10

Highs (northern by lows)

Question 11

Is a cyclone low or high pressure system?

Answer 11

low

Question 12

How do low pressure systems form?

Answer 12

When warm air rises

Question 13

Characteristics of low pressure systems?

Answer 13

Unstable atmospheric conditions- cloudy, rain, wind.

Question 14

Does air increase or decrease towards centre of low pressure systems?

Answer 14

Decreases

Question 15

Which way does air flow TOWARDS centre in low pressure systems?

Answer 15

Clockwise towards centre

Question 16

What is a front?

Answer 16

Boundary between two different (humidity, temperature) air masses

Question 17

How do cold fronts form?

Answer 17

When mass of cold air overtakes slower-moving mass of warm air, forcing it to rise (clouds > rain)

Question 18

Characteristics of cold fronts?

Answer 18

As cold front passes, temps fall, rain, wind direction changes

Question 19

What symbol is used for cold fronts?

Answer 19

Blue triangles (triangles point in direction front is moving)

Question 20

What direction do weather systems tend to move across southern Aus?

Answer 20

West > East

Question 21

What direction do weather systems tend to move across northern Aus?

Answer 21

East > West

Question 22

What is the biggest factor on temperature?

Answer 22

Seasonality

Question 23

What are 4 other factors that influence temperatures?

Answer 23

Extent of cloud cover; frontal activity (fall after cold fronts); wind direction (wind from south cooler, from north hotter); proximity to large water bodies (smaller diurnal range)

Question 24

T or F- high pressure systems associated with sinking air which becomes warmer and better able to retain moisture

Answer 24

t

Question 25

Wind from central Australia will likely bring

Answer 25

drier conditions

Question 26

Wind blowing onshore can often bring

Answer 26

Rain

Question 27

The closer the isobars, the stronger the...

Answer 27

Wind

Question 28

The end of a wind bar opposite the feather indicates

Answer 28

The direction the wind is coming from (draw a compass over the dot)

Question 29

Does air pressure always want to move from high to low, or low to high?

Answer 29

High to low

Question 30

How to write air pressure of a place located between isobars?

Answer 30

As a range e.g. 1012- 1016 hPa

Question 31

Are cold or warm fronts more common in Aus?

Answer 31

Cold

Question 32

Are ridges high or low pressure?

Answer 32

High

Question 33

What is a famous ridge in Australia

Answer 33

Sub-tropical ridge

Question 34

Are troughs high or low pressure?

Answer 34

Low

Question 35

What is a trough?

Answer 35

An elongated area where atmospheric pressure is low compared to surroundings. Separate 2 air masses (usually moist air one side, dry on the other)

Question 36

Famous trough in Aus?

Answer 36

Monsoon trough- moves over northern Aus annually, drawing in moist air from ocean> monsoon

Question 37

Where is the sub-tropical ridge during Nov > April?

Answer 37

South of Aus. High pressure systems move eastward along ridge, suppressing cold front activity

Question 38

What happens when the sub-tropical ridge moves north and remains over the continent from May- Oct?

Answer 38

Cold fronts associated with low pressure systems extend into Southern Aus > cold SW winds, showery.

Question 39

Do ridges generally result in drier conditions?

Answer 39

Yes

Question 40

Why are high pressure ridges sometimes associated with coastal showers?

Answer 40

When they bring onshore winds along the east coast

Question 41

What can often precede a cold front?

Answer 41

A trough (region of low air pressure)

Question 42

Are low pressure systems associated with descending or rising air?

Answer 42

Rising

Question 43

How do warm fronts form?

Answer 43

Warm air follows warm front, when reaching cool air the warm air is forced to rise, condensing, precipitation.

Question 44

Do warm fronts result in more severe weather changes compared to cold fronts?

Answer 44

No- more gradual

Question 45

What symbol is used to show developing warm or cold front?

Answer 45

Small squares in between triangle/semi circles

Question 46

What symbol is used for warm fronts?

Answer 46

Red semi circles on a line

Question 47

What symbol is used for a stationary front?

Answer 47

Alternating red semi circle on one edge, blue triangle facing other way

Question 48

What is a stationary front?

Answer 48

Different weather on either side- boundary hardly moves and can last for days

Question 49

What is an occluded front?

Answer 49

If cold front catches up to warm front. Mix of cold and warm air= thick cloud, rainfall.

Question 50

What symbol is used for occluded front?

Answer 50

Purple adjacent semi circle and triangle on same side of line

Question 51

What symbol is used for trough?

Answer 51

Dash line

Question 52

What symbol is used for monsoon trough?

Answer 52

Alternating dash and dot on line