The average temperature for Sydney in May is 19.5 C, according to the Australian Bureau of Meteorology (BOM), but with unusual highs of 28 C. This hot weather is planned to continue for weeks in many parts of Australia. Warm ocean temperatures is the cause for milder weather across the eastern states as well as the east coast and over northern Australia.
El Nino–Southern Oscillation
It is unusual that ocean temperatures are still warm, as BOM has already declared the start of an ENSO-neutral period. The ENSO-neutral season, which is the El Nino–Southern Oscillation, arrives before the La Nino and after La Nino. In an interview with the Guardian duty forecaster, Philip Landvogt explained that most of the eastern states had been experiencing these warmer conditions.
"All the way from Brisbane down to even Hobart is warmer than average for this part of year," said Landvogt.
BOMs round up
BOM states in its ENSO round up that the current time of ENSO-neutral is because sea surface temperatures over the tropical Pacific have reduced to neutral levels. These sea surface temperatures are backed up by cooler-than-average waters below the surface.
Common atmospheric indicators are the trade winds as well as cloudiness near the date line. Another indicator for ENSO-neutral is the Southern Oscillation Index – which is also back to a neutral position.
Warmer conditions not leaving yet
"The combination of those two factors has been the reason we've had these warm temperatures," said Landvogt.
Landvogt said the hotter weather was set to remain for at least a week in many parts of Australia. Brisbane currently has highs of 13 C and Sydney with highs of 19 C. Early in the morning, Sydney will be cloudy with patchy fog in the outer west.
By David Francis