Cooler temps for Perth this summer

El Niño could bring cooler temperatures to Perth this summer.

According to The Bureau of Meteorology an El Niño event is still on the cards for the end of 2018/ early 2019.

An El Niño event is caused by two temperature anomaly's of seperate pressure systems in the Pacific that when come together, greatly affecting weather patterns and systems across the globe. They consist of an atmospheric pressure system and an ocean system.

For more information on an El Niño check out a previous article posted HERE.

Data released by the Beuro of Meteorology shows temperatures in Pacific sea recording above the average threshhold that would cause an El Niño, but atmosphere temperatures remain normal. This means the two systems which cause an El Niño are yet to interact with each other, but if they do, we can expect an El Niño event to occur for 2019.

Impacts of El Niño in Australia

In Australia this has huge impacts across the country especially in the east, where higher than average temperatures have occurred, resulting in major draughts and devastating wildfires.

In Western Australia the El Niño has the opposite effect and brings cooler tempretures along the coast. This is due to the Leeuwin Current that flows from the tropic waters of Indonesia down along Western Australia to the Southern Ocean.

Aerial view over Fremantle Port out towards Rottnest, where the Leeuwin current hugs the coast.
Aerial view over Fremantle Port out towards Rottnest, where the Leeuwin current hugs the coast.

The Leeuwin Current cools in El Niño

During an El Niño event the Leeuwin Current slows causing cooler temperatures to fall along the coast.

One of the indicators of the Leeuwin Current slowing from an El Niño event can be predicted by comparing the surface temperatures of the Pacific Sea and the sea level of Fremantle in Western Australia.

Fremantle is a prime indicator of the strength of the Leeuwin Current and the surface temperatures in the Pacific have a strong correlation to the sea levels in western equatorial Pacific; meaning if the Pacific sea levels are dropping in the Pacific, the sea levels in Fremantle will follow and this slows the Leeuwin Current.

As the Leeuwin Current slows, tempretures fall below average and we could expect cooler summer along the coast for 2019 in Western Australia.

Fremantle El Niño3.4 Graph

This graph shows the correlation between the Pacific Sea temperatures and sea levels in Fremantle.

El Niño Pacific Tempretures 2019

This graph shows the latest recorded temperatures in the Pacific Sea and indicates a steady rise in temparetures, which could indicate a possible El Niño event for 2019.

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