Where do blocking anticyclones typically form in the southwest Pacific Ocean?

Blocking anticyclones typically form near the Chatham Islands and southwest of New Zealand due to specific atmospheric and oceanic conditions in the southwest Pacific region. This area is influenced by the interaction of different air masses, particularly the subtropical high-pressure systems and the prevailing westerlies that dominate in this part of the world.

When these high-pressure systems establish themselves near the Chatham Islands, they can become stationary or "blocked," leading to prolonged periods of settled weather, often characterized by clear skies and light winds. This blocking pattern can also influence weather systems further afield by disrupting typical west-to-east movement, which can result in unusual weather patterns as systems are forced to navigate around the blocking high.

The geographic position of the Chatham Islands plays a crucial role in this phenomenon, as it is situated at a point where these atmospheric influences converge. The characteristic nature of blocking anticyclones contributes to the regional climate, affecting not just New Zealand but also the broader southwest Pacific area.