National Climate and Water Briefing€¦ · 27 August 2015 • Indian Ocean Dipole currently neutral • Warmer than average waters across Indian Ocean Basin . Sea surface temperature

Bureau of Meteorology www.bom.gov.au National Climate and Water Briefing 27 August 2015

National Climate and Water Briefing Wheat silos Mintaro South Australia


Welcome

Dr Rob Vertessy Director


Climate conditions and outlook

Joel Lisonbee Senior Climate Liaison Officer


Recent conditions • Recent conditions

• Climate influences

• Rainfall and temperature outlooks


• Event totals (3 days to 9am this morning)

• 478 mm at Beaumont (Kangaroo Valley)

• 413 mm at Nowra

• 200 mm+ at Wollongong to Narooma received

• Moderate flooding for the Shoalhaven river and Sussex inlet.

• Warragamba Dam spilt this morning, first time since 2012.

NSW weekly rainfall total, ending 26th August.

NSW East Coast Low

400 mm 300 mm 200 mm 150 mm 100 mm 50 mm 25 mm 15 mm 10 mm 5 mm 1 mm

Satellite imagery


• Two significant cold outbreaks in southeast

• Heatwave in north

• Nationally, Australian temperatures were 0.4 °C above average

Temperature

July 2015

Maximum temperature deciles Minimum temperature deciles


Rainfall deciles, May–July 2015

Rainfall

Rainfall deciles, July 2015

July

• Australian rainfall 31% below average

• All States and Territories below average

May–July

• Australian rainfall 19% below average

• Southwest Western Australia 2nd lowest on record


Rainfall deficiencies

July 2014 – July 2015 October 2012 – July 2015

Update on wed to include southeast nsw rain

Percentage of average August rainfall 1–26 August 2015


Climate influences • Recent conditions




El Niño Sea surface temperature

July 2015

NINO3.4 recent anomalies • July: +1.5 ⁰C

• Latest weekly: +1.9 ⁰C (to 23rd August)

NINO3.4


El Niño Sub-surface and

atmosphere

Southern Oscillation Index Pacific Ocean sub-surface temperatures

May

June

July

August

Cloud patterns Three months to 22 August 2015

More cloud Less cloud than normal than normal

30-day moving SOI January 2013 – August 2015


• Develop in late autumn–winter

• Peak at end of year

• Dissipate in autumn

Of 26 El Niños in past 100 years:

• 50% have transitioned to Neutral

• 40% have transitioned to La Niña

• 10% followed by El Niño

Ten El Niño events since 1980

El Niño evolution

-3.2

-2.4

-1.6

-0.8

0

0.8

1.6

2.4

3.2

Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep Oct

Nov

Dec Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep Oct

Nov

Dec

year1 year2

1982-831987-881991-921993-941994-951997-982002-032006-072015-16

NIN

O3.

4 (°

C)

-3.2

-2.4

-1.6

-0.8

0

0.8

1.6

2.4

3.2

Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep Oct

Nov

Dec Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep Oct

Nov

Dec

year1 year2

1982-831987-881991-921993-941994-951997-982002-032006-072009-102015-16


NINO3.4 forecasts from eight international climate models

El Niño Model outlook


El Niño Global impacts

• Papua New Guinea drought and frosts

• Record typhoon season in north Pacific

• Weaker than usual Indian Monsoon after strong start

• Very wet in Argentina, Paraguay and southern Brazil

Can build on this one


El Niño Global impacts

Record global temperatures

• Hottest July

• Hottest month

• Hottest year-to-date

• Hottest 12-months


• Indian Ocean Dipole currently neutral

• Warmer than average waters across Indian Ocean Basin

Sea surface temperature anomalies, week ending 23 August 2015

2015

Data: ERSST v4 1981–2010 base period 0–40°S 30–120°E

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1950

1953

1956

1959

1962

1965

1968

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

2001

2004

2007

2010

2013

July temperature anomalies Southern Indian Ocean

1997

2015

1982

Indian Ocean


• Indian Ocean Dipole currently neutral

• Warmer than average waters across Indian Ocean Basin

Sea surface temperature anomalies, week ending 23 August 2015

2015

Indian Ocean Dipole Model outlook


Recent conditions • Recent conditions




Rainfall outlook

Spring 2015

Chance of exceeding median rainfall September–November

Chance of exceeding median rainfall September

Chance of exceeding median rainfall October


Rainfall outlook

Spring 2015

Chance of exceeding median rainfall September–November


Temperature outlook

Spring 2015

Chance of exceeding median maximum temperature September–November

Chance of exceeding median minimum temperature September–November


Northern rainfall onset outlook

Chance of early northern rainfall onset in 2015

Average date of northern rainfall onset (1960–2009)

Normal onset:


In summary

• El Niño is dominant climate driver globally

• Strong El Niño does not always mean strong rainfall impact

• West likely to be wetter than usual

• Extended frost risk period

• Northern rainfall onset likely to be later than normal in north and earlier in central parts


Thank you

Questions?

Joel Lisonbee Senior Climate Liaison Officer


Hydrologic conditions and outlook

Dr Christopher Pickett-Heaps Hydrologist, Seasonal Streamflow Forecasting Brindabellas, ACT (C. Pickett-Heaps)



• Recent hydrologic conditions

• Water storages

• Streamflow outlook


Rainfall deciles Effective rainfall

Recent conditions

July 2015


Upper-layer soil moisture 1-month change in upper-layer soil moisture

Recent conditions

July 2015


Lower-layer soil moisture 12-month change in lower-layer soil moisture 1-month change in lower-layer soil moisture

Recent conditions

July 2015


Observed streamflow

July 2015

• High flow at 23 locations

• Near median flow at 67 locations

• Low flow at 103 locations


May 2015 June 2015 July 2015

Observed streamflow

Southeast Australia


Observed streamflow trend

PR

OP

OR

TIO

N O

F S

ITE

S (%

) AC

RO

SS

AU

STR

ALI

A


Serpentine Reservoir, Western Australia

Hawkesbury – Island Hill, NSW

Cumulative streamflows

CU

MU

LATI

VE

FLO

W (G

L)

CU

MU

LATI

VE

FLO

W (G

L)


Cumulative streamflows

CU

MU

LATI

VE

FLO

W (G

L)

Total inflows Melbourne Water

Thomson O’Shannassy Upper Yarra Maroondah

CU

MU

LATI

VE

FLO

W (G

L)

Total inflows southern Murray–Darling Basin

Dartmouth Hume Eildon Goulburn Weir

El Niño progression?

August 2015 streamflow forecast

1997 and 1982 2015




• Water storages



Water storages

As at 20 August 2015


Water storage levels

Change from last year

20 August 2015 20 March 2015




• Water storages



• High flow at 17 locations

• Near median flow at 56 locations

• Low flow at 122 locations

• Generally moderate to high forecast skill

Forecast skill Most likely forecast outcome

Streamflow outlook

August–October 2015


In summary • Low observed streamflows for July 2015

• Below-average lower-layer soil moisture in western Victoria and southwest Western Australia

• Below-average cumulative streamflows for major storages in southeastern Australia

• Low streamflows likely in August–October for majority of locations across southern Australia


Thank you

Questions?

Dr Christopher Pickett-Heaps Hydrologist, Seasonal Streamflow Forecasting


Next briefing

24 September 2015

Documents

National Climate and Water Briefing€¦ · 27 August 2015 • Indian Ocean Dipole currently neutral • Warmer than average waters across Indian Ocean Basin . Sea surface temperature