Why is Australia's East Coast drier than the other East Coasts? (climate, rainfall)

[Ethereal]

Compare the East Coasts of USA, South America and East Asia...They have lush rainforests, abundant rainfall (even much further inland) and they appear very green in space imagery. Whereas, in Australia, the East Coast (NSW/QLD) is partially semi-arid (rainforests or greenery seem to diminish just halfway in). Slightly inland in NSW, the rainfall gets down to around 600mm-800mm (23 - 31in) and you'll soon see dry woodlands. Whilst the American, Chinese and South American East Coasts' rainfall is still around 1,100mm (43in) further inland and the landscape appears very lush.

What causes the dryness on Australia's East Coast when a huge portion of the other East Coasts is excessively wet and lush in comparison?

[Candle]

Good question...

I think the southern area of Africa has a similar pattern as well.

Take Durban for example:
Durban - Wikipedia, the free encyclopedia

Areas farther west are considerably drier than Durban, which is pretty dry itself. Plus, Durban is reasonably drier even in comparison to coastal locations at comparable latitude in eastern Australia (similar precipitation amount to Brisbane but much drier than Coffs Harbour for example).

[Superluminal]

Possible answers:
1) The desert and semi-arid areas of Australia take up a much greater proportion of its landmass than either the US or China.
2) The relatively wet coastal strip is just that - a strip, with a mountain range which closely follows this coastline, from north to south, blocking rain-bearing winds and preventing them from penetrating very far inland.
3) Unlike East Asia, eastern Australia lacks a powerful summer monsoon, which counterbalances the drought from the Siberian winter monsoon. Therefore, it is far less wet.
4) Unlike North America, there is no general pattern of a collision of westerly and northwesterly winds originating in the Pacific (and subsequently dried through its descent down the Rockies) and clashing with moist and humid Gulf of Mexico and resulting in low-pressure systems tracking eastwards. -=This is a major precipitation generator which Australia lacks. Unlike both East Asia and Australia, this situation prevails for much of the year, meaning eastern N.America is seldom very dry for long.

[Ethereal]

Originally Posted by Candle

Good question...

I think the southern area of Africa has a similar pattern as well.

Take Durban for example:
Durban - Wikipedia, the free encyclopedia

Yes, it does too, interestingly.

I didn't include it only because South Africa is relatively smaller (or narrower) than the other country with east coasts.