Wam, bam, (bad storms and fire), but no thanks SAM

Climate drivers refuse to budge leaving longer wait for rain

News
Aa

BOM analysis puts off southern climate driver change for month

Aa
A firefighter rescue near Tamworth this week. More difficult fire days are expected as the dry continues.

A firefighter rescue near Tamworth this week. More difficult fire days are expected as the dry continues.

It's the climate driver we all want to break up, but the system known as SAM (Southern Annular Mode) that can beset southern Australia with westerly winds and reduce rainfall, will be sticking around until at least Christmas.

That's the latest information provided by the head of climate prediction at the Bureau of Meteorology, Dr Andrew Watkins, who says SAM's persistence is very unusual.

A negative SAM was forecast to break up in mid-December, enabling more moist winds to drive over the south of the continent, but now the BOM doesn't feel it will break down until some time in January when it is expected to move to rain-enhancing positive mode.

"Our best advice is that it is unlikely to break down until late December or into January," Dr Watkins said.

A fire believed to be deliberately lit has burnt through $10 million worth of timber at a pine plantation near Nundle. Dry lightning strikes have added to the fire crisis.

A fire believed to be deliberately lit has burnt through $10 million worth of timber at a pine plantation near Nundle. Dry lightning strikes have added to the fire crisis.

"Usually it breaks down after a couple of weeks but this event has been going on since November. It's quite unusual to have such a long negative (of SAM)."

A rare event heating up the stratosphere above the South Pole (southern stratospheric warming) is being blamed for maintaining a negative SAM for such a long period.

The news from the north is not good as well as, the monsoon was six weeks late leaving India, meaning it is unlikely a positive Indian Ocean Dipole (IOD) will probably break down until also well into January.

We are entering summer in a difficult position. - Dr Andrew Watkins, Bureau of Meteorology head of climate predictions

Related: Bureau of Meteorology forecasts northern Australia to stay dry into January

It means trade winds will not bring the warm water needed to help moisture forming events over the Indian Ocean near Indonesia that help bring moisture down to the Australian continent.

Here is the BOM's video on climate drivers (but noting it was done before it is was known that the SAM event would last possibly into January) :

On the good side though the Pacific Ocean is not showing any sign of breaking into a dry El Nino phase, but the dice on whether it gives us a wetter or drier outlook "will be rolled again in autumn".

Dr Watkins also said that it's probably going to be one of the driest springs on record for Australia, with official results after the end of the month.

"We are entering summer in a difficult position."

Related:Drought not ready to let go of grip - yet

Meantime, storms have brought some welcome rain to the driest parts of the state in the north, but it was not widespread. They have also ignited more fires with dry lightning strikes.

Up to 70mm fell in some parts near Tenterfield last Sunday, and up to 50mm east of the town which has been beset by drought for two years and by fires since last September.

Locals were given the incredible sight of Tenterfield Creek in flood as the rain lifted the town's water supply level by 10 per cent adding to the glee of a recently found bore. There was hail damage in town.

Related: Tenterfield gets 70mm downpour

Rain totals for the week so far were mixed but at least parts of the dry north and north-west received some solid totals for a change. In the Northern Tablelands there was 33mm at Armidale, 28mm at Deepwater, 46mm at Glen Innes, and Tingha 47mm. The rainfall was cruel and mixed. Some places near the Tenterfield downpour received nothing. Dams filled in some area- but there was no grass and no stock.

On the North-West Slopes there was some good rain including Moree with 22mm, Mungindi with 27mm, Gwabegar with 25mm, Narrabri with 34mm and Wee Waa with 25mm. Other totals during the week included Tamworth 12mm, Barraba 12mm, Coonabarabran with 18mm and Bathurst with 10mm. Mt Seaview on the Mid-North Coast topped the charts with 114mm.

Aa

From the front page

Sponsored by