Sydneysiders continue to swelter through uncomfortable nights as La Nina helps to drive up the humidity to record breaking levels.
The average humidity in Sydney this January has reached 85 per cent in the mornings and 73 per cent in the afternoons, well above what the city would usually see at this time of year.
The historical mean January humidity, recorded between 1955 and 2010, was 71 per cent in the mornings and 62 per cent in the afternoons.
Weather bureau meteorologist Dean Narramore said the hot and sticky weather was being driven by wind and above average ocean surface temperatures.
“It’s really a humid summer. The temperatures are really warm off the east coast of Australia, about one or two degrees above average,” he told NCA NewsWire on Wednesday.
“That, combined with easterly winds, has been draggingxjmtzyw a really warm and humid air mass over eastern Australia which is causing this really long run of warm, humid and sticky nights and stormy days.”
Mr Narramore said the La Nina weather event, which was confirmed by the Bureau of Meteorology in November, was leading to warmer sea surface temperatures off the east coast and propelling more moisture into the atmosphere.
“La Nina generally leads to above average sea surface temperatures across northern and eastern Australia, running one to two degrees above average, leads to more evaporation and more warm air over the ocean,” he said.
“We’re just seeing it for weeks and weeks and weeks. That’s why we’re seeing that long duration of a really cloudy, wet summer.
“We’re only three weeks into January, but just to show how warm it has been: the monthly average is currently running two degrees above average for daytime temperatures and 2.5 degrees above average for night-time temperatures.”
He said the run of warm weather would continue in Sydney for the rest of the week, with overnight temperatures staying above the 20-degree mark.
“We should see more sunshine over the weekend,” he said.
While La Nina continues in the tropical Pacific, the weather bureau’s climate models suggest the weather phenomenon is at or near its peak, with a return to neutral conditions likely early in autumn.
