Understanding the Significance of the November 2018 Queensland Heatwave

The Queensland November heatwave of 2018 will be remembered as one of the most extraordinary heatwaves in history.  Records were not just broken – they were obliterated and these included sites that have recorded temperatures for decades.  Normally when temperature records are broken (especially long-standing ones like Cairns), the it’s by a few tenths of a degree.  Traditionally the only records that are broken by more than a degree or two are those with much shorter record timeframes. 

While records were broken across northern to central eastern Queensland, Cairns was certainly the standout with the old November record being broken during five consecutive days.  That is, five days in a row from November 26 to November 30 recorded a temperature higher than ever previously recorded at Cairns Airport.  Many locations also recorded not just their highest November temperature on record, but their overall highest temperature on record which is also quite extraordinary given it lies just outside the (traditional) hottest time of year.

November 2018 is likely to be the first month of what will be an El Nino year, though it’s difficult to say whether this is the sole cause of the heatwave and it’s likely we saw a combination of factors come together to generate the heat. 

Traditionally westerly winds along the Queensland coastline are quite rare during the warmer months of the year, but can happen further south in southern Queensland which is more prone to the impacts of mid-latitude systems that may generate these westerly winds.  Normally the warmer months are marked by warm and humid southeast or northeast winds.  While temperatures are still often hot and muggy, they seldom approach the high 30s let alone reaching 40C along the coast in central to north Queensland.  It was these strong, westerly winds that have also been responsible for the horror fire conditions that have since plagued the state.

During winter, westerly winds are more common but during winter the interior of the country is quite cool so many residents associate westerly winds with cooler conditions.  It’s different in the leadup of summer where temperatures across the interior are much hotter meaning westerly winds during (and around) summer produce hot conditions.

Additional graphs for Townsville, Proserpine, Cooktown, Ayr and Mackay M.O have also been included to demonstrate the significance of this heatwave.