Landholders in NSW can expect higher than normal fire risk in December as the two major influences on the weather idle in neutral.
A drier and windier December is expected, with fronts moving up from the south that would normally be blocked by lower-sitting high pressure systems over the continent.
Weatherzone meteorologist Rob Sharpe said the “tap from the north-west had been turned off”, referring to the wet weather that had drenched most parts of the state from May to September.
With both the Southern Oscillation Index and the Indian Ocean Dipole in neutral, the continent was now subject to fronts coming higher up from the Antarctic region.
“With the SOI and the IOD out of action it is up to other climate drivers to run the weather,’’ Mr Sharpe said. ‘’This means the Southern Annular Mode (SAM) is likely to occur further north. That means more stronger fronts over southern Australia. That will bring the heat from the west to the east, with stronger winds and increased fire risk during December compared to normal.
“Basically hotter and windier periods. That is the consensus forecast for December”.
It may also mean fewer storms in December, but if they occur they could be more severe.
He said it was unlikely the neutral La Nina-El Nino situation would resolve itself either way now summer had started. The neutral SOI was likely to set-in over the whole summer. “It has been in neutral for a while and if it was going to change to La Nina it should have done that by now.’