National Climate and Water Briefing...July-September 2010 July-September 2011 Month to Date: October 10 th coolest on record 8 th warmest on record Recent rainfall trends: the global

Lake Eyre - © Pete Dobre

National Climate and Water Briefing

October 2011


Climate conditions and outlook

•  Recent climate conditions and trends •  Current state of key climate drivers •  Climate outlook


Calculating deciles

Sort and rank

Historical record Sorted historical record

Group into tenths for deciles

Deciles 1 to 10

1 2 3 4 5 6 7 8 9 10


A tale of two years: rainfall

July – September 2010 July – September 2011 Month to Date: 20 October

Wettest on record Rank 45 of 112 years


A tale of two years: upper layer soil moisture

September2011September2010


A tale of two years: lower layer soil moisture

September2010 September2011


A tale of two years: maximum temperature

July-September 2010 July-September 2011 Month to Date: October

10th coolest on record 8th warmest on record

Recent rainfall trends: the global picture Thailandflooding2011

Tuvaludrought2011

h8p://www.cpc.ncep.noaa.gov/products/fews/AFR_CLIM/afr_clim_season.shtml

SOMALIAKENYA

ETHIOPIA

EastAfricandrought2011


Recent rainfall trends: the global picture

Typical La Nina Summer Impacts


Key points

1.  Australian spring of 2011 has been vastly different to that of 2010

2.  Effects of the La Niña from last year and emerging event this year are being felt around the world

bom.gov.au/climate/ahead



•  Recent climate conditions and trends •  Current state of climate drivers •  Climate outlook


La Niña – the return

Sea surface temperature difference from average Southern Oscillation Index

2010

2011

La Niña

- 8 ▼

+8 ▲

El Niño


A tale of two years: change in the Indian Ocean

2010

+IOD

-0.4 ▼

+0.4 ▲

-IOD

2011

DifferencebetweenSeptember2011&September2010OceanTemperatures


• September2010:warmwatertothenorthofAustralia(2010–recordwarmAustralianoceantemperatures)• September2011:averagetocoolwatertothenorthofAustralia

A tale of two years: Australian sea surface temperatures

September2010 September2011 Weekending16October2011


Key points

1. A late forming La Niña is developing in the tropical Pacific 2. Current observations are clearly different to this time last year 4. Expect warming in the Indian Ocean with start of Monsoon 3. Deep soil moisture is still high from summer rainfall while top

layers have dried




•  Recent climate conditions •  Current state of key climate drivers •  Climate outlook


Pacific Ocean – forecast

•  La Niña conditions forecast by most models •  Event has started late in the

year •  Current conditions indicate a

weaker event than in 2010-11

Australia’sPOAMAmodelforecastforNINO3.4

bom.gov.au/climate/enso

El Niño

- 0.8 ▼

+0.8 ▲

La Niña

El Niño

La Niña


Rainfall outlook for November 2011 to January 2012 bom.gov.au/climate/ahead

Seasonal outlook for November 2011 – January 2012 Global model outlooks POAMA outlook for Nov -Jan

20102011


Temperature outlook for November to January

•  Warm days in the north and south, cool days on the QLD/NSW border

•  Warm nights over most of southern and eastern Australia

Minimum temperature Maximum temperature

Percentage chance of above median

Percentage chance of above median

Tropical cyclone outlook: November 2011- April 2012 • Above average tropical

cyclones forecast in Australian region and western region of South Pacific

• Below average tropical

cyclones forecast for eastern region of South Pacific


Key points

1.  La Niña developing in Pacific – indicators much weaker than at this point in 2010 2.  Rainfall inland including Murray-Darling Basin less than normal 3.  Outlook for wetter conditions in east of Australia 4.  Tropical Cyclone forecast for above average number of cyclones in the Australian

region



Hydrologic conditions and outlook

•  Trends in water storage and rainfall •  Conditions in Murray-Darling Basin •  Forecasts for the next three months •  New forecast locations


Water storage levels – current status

water.bom.gov.au


Lake Eildon reaching 100%

Image:TheAge


Water supply storages rising

Thomson Dam (water supply for Melbourne) Warragamba Dam (water supply for Sydney)


Northern Australia storages

Argyle Dam (Ord River in Western Australia) Burdekin Dam (Burdekin River in Queensland)


Drier winters and wetter summers?

Winter and summer rainfall trends over the last 30 years 1981-2010

Example products available in the Australian Water Resources Assessment 2010 ([email protected])

Australian Water Resources Assessment 2010 (released

inNovember)





Most significant September rainfall at end of the month

One month rainfall deciles for September 2011 Total rainfall recorded in the week to 9.00 am on 1 October


Low September streamflows

One month observed streamflow terciles for September Three month observed streamflow terciles for July to September

High flowNear median flowLow flow


South-east Murray-DarlingSeasonal Streamflow Observationsfor July to September 2011



South-east Murray-Darling Monthly Streamflow Observationsfor September 2011


Drying in lower layer soil moisture

June 2010 lower layer soil moisture September 2011 lower layer soil moisture March 2011 lower layer soil moisture





How have the forecasts been going ?

July to September • mostly moderate skill • 14 hits, seven misses • all misses were by one tercile

South-east Murray-Darling Seasonal Streamflow Forecastsfor July to September 2011

What is a tercile hit ?

A tercile hit is when the observed streamflow for the forecast period is in the same tercile as the most likely tercile from the forecast pie chart

Most likely tercile

Forecast as tercile pie chart

Low flow

Near median flow

High flow

Sorted Historical Streamflow Record

Observed streamflow

Low flow

Near median flow

High flow

Rank/Year

Str

eam

flo

w

July to September forecasts


Low to near median flows most likely

•  October to December forecast – low flows more likely for the

western catchments – near median flows are more

likely in eastern catchments – moderate to high skill at most

sites

Forecast confidence





New forecast sites

•  Initial investigations on sites in every state and territory •  Seasonal forecasting data needs – quality, length of record, available in real time

•  High Quality Streamflow Reference Stations – basis for further site selection

– comprehensive stakeholder engagement and site selection

Potential Sites


New forecast sites

•  25 new locations added – Richmond, Shoalhaven, Upper Murray, Manning, Murrumbidgee, Lachlan, Gwydir and Macquarie basins

•  Less skill than current sites •  Available on password protected experimental

website


Station Name Drainage Division River Basin Richmond River at Wiangaree South-East Coast Richmond Nowendoc River at Rocks Crossing South-East Coast Manning Shoalhaven River at Warri South-East Coast Shoalhaven Tambo River at Swifts Creek South-East Coast Tambo Wonnangatta River at Waterford South-East Coast Mitchell Latrobe River at Willow Grove South-East Coast Latrobe Maragle Creek at Maragle Murray-Darling Upper Murray Jingellic Creek at Jingellic Murray-Darling Upper Murray Snowy Creek at below Granite Flat Murray-Darling Upper Murray Tarcutta Creek at Old Borambola Murray-Darling Murrumbidgee Halls Creek at Bingara Murray-Darling Gwydir Abercrombie River at Abercrombie Murray-Darling Lachlan Boorowa River at Prossers Crossing Murray-Darling Lachlan Ovens River at Bright Murray-Darling Ovens Fifteen Mile Creek at Greta South Murray-Darling Ovens

New public sites in November

Tour of experimental forecast sites


Key points 1.  Lake Eildon reaching 100%, spilling for first time since 1996 2.  Increasing storage levels in Perth, Melbourne and Sydney 3.  Forecast for southeast Murray-Darling –  low flows more likely for western catchments –  near median flows more likely for eastern catchments –  moderate to high forecast confidence

4.  Australian Water Resources Assessment 2010 and forecasts for 15 new locations in November

bom.gov.au/water/ssf


Documents

National Climate and Water Briefing...July-September 2010 July-September 2011 Month to Date: October 10 th coolest on record 8 th warmest on record Recent rainfall trends: the global