Where has winter gone? July temperatures smash averages
YOU would think it was autumn on the Northern Rivers today, with temperatures set to rise more than 5C above the July average.
Lismore is expected to reach 24C today and tomorrow, and 26C in Casino - temperatures you would expect in April or May.
This comes after certain NSW towns just had their warmest July day in more than half a century.
It's been a warmer than average week for Lismore with maximum temperatures recorded as 21C yesterday, 23C on Wednesday and 21.5C on Tuesday - between 0.2 and 2.2C warmer than average.
Weather Zone reported: "A stream of air flowing over NSW from central Australia caused temperatures to climb 5-9C degrees above average across most of the state yesterday.”
But a change could be coming, bringing a more winter-like feel back to the region.
"The warm air is expected to linger over northern NSW today, although a cooler south-westerly change will flush the heat out by the weekend.”
These trends follow a warmer than average June for Australia as a whole - the national monthly mean temperature was 0.33 °C above average.
The average daily maximum temperature for July across the whole of Northern Rivers sits between 15-21C.
The highest average for Lismore in July is recorded as 20.8C at Lismore Airport, and 22.7C at Casino Airport by the Bureau of Meteorology.
According to the bureau, it hit 22.1C last year which was the highest temp recorded in Lismore in July since at least 2002.
Northern Rivers Climate Patterns
BoM Climatologist David Martin said the Northern Rivers had above average temperatures in most of district for the last financial year.
"It wasn't quite record-breaking like parts of NSW but it was still warmer than average, and below average rainfall,” Mr Martin said.
He said there was no strong climate driver behind the weather.
"The dryness inland has been affecting the heating of the continent and making the days warmer.”
"Off the coast of the Northern Rivers the sea's surface temperatures were highest on record for July to June financial year and very much warmer than average for eastern Australia.”
In terms of a colder change, Mr Martin said it didn't look good for the Northern Rivers.
"Looking at a longer three month outlook there is a high probability of warmer days and nights along the eastern seaboard and the Northern Rivers area,” he said.
"There is also a below average chance of above average rainfall.”
He said temperatures are warming consistently across NSW and Australia, with about a 1C warming across the century.
El Nino Watch Activated
The Bureau's ENSO Outlook was upgraded from inactive to El Niño watch in June.
Potential effects of El Niño on Australia include:
- Reduced rainfall
- Warmer temperatures
- Shift in temperature extremes
- Increased frost risk
- Reduced tropical cyclone numbers
- Later monsoon onset
- Increased fire danger in southeast Australia
- Decreased alpine snow depths
Bom reported last month that although the El Niño−Southern Oscillation (ENSO) remains neutral, latest model outlooks and recent warming in the tropical Pacific, mean the likelihood of El Niño developing in spring has increased to around a 50 per cent chance - roughly double the normal probability of an El Niño developing.
They also reported ocean indicators show some signs of potential El Niño development, with with sea surface temperatures in the eastern Pacific Ocean slowly warming since April, while waters below the surface of the tropical Pacific are now warmer than average.
During El Niño, rainfall in eastern Australia is typically below average during winter and spring.