the national climate and water briefing · high flow near median flow low flow victoria monthly...

Lake Eyre - © Pete Dobre

The National Climate and Water Briefing

February 2012


Climate conditions and outlook

Dr Andrew WatkinsManager Climate Prediction Services



• Recent climate conditions and trends

• Current and forecast state of key climate drivers• Climate outlook


Calculating deciles

Sort and rank

Historical recordHistorical record Sorted historical record

Group into tenths for deciles

Deciles 1 to 10

1 2 3 4 5 6 7 8 9 10


Recent rainfall

January 2012 October 2011 – January 2012

• Victoria: 32mm 2012; 121mm 2011:

• Northern Territory: almost half (84mm vs 163mm)

• Eastern Australia: driest January since 2006

• Wetter conditions more to the west in the 2011–12 La Niña

• Australia: 2-year rainfall highest on record (beating 1973–74)

October 2010 – January 2011

• Victoria: 32mm 2012; 121mm 2011:

• Northern Territory: almost half (84mm vs 163mm)

•• Eastern Australia: driest January since Eastern Australia: driest January since 2006

• Wetter conditions more to the west in the 2011–12 La Niña

• Australia: 2-year rainfall highest on record (beating 1973–74)


Maximum temperature


• Western Australia: 3rd coolest January on record

• Australia: coolest January since 2000

• Top end warmth: Darwin had a 10-day period of no rain in January


Minimum temperature


• Southwest Western Australia: warmest January on record (and warmest four months)

• Tasmania: 6th warmest January on record


La Niña: Vegetation Index difference from normal

January 2009 January 2011 January 2012


La Niña: deep soil moisture ranking

January 2009 January 2011 January 2012

• Darkest blue – wettest soils on record

• Darkest red – driest soils on record


Global ConditionsJanuary 25January 25––February 1 2012February 1 2012

Zurich 1864-2012 Years with a 14-day average colder

than -6 (light blue) and -9 (dark blue)

• European cold wave 2012 – at least 650 people have lost their life; most fatalities in Russia, Ukraine, Poland

• 4th warmest January on record in USA (3.1°C above average)

• Good October–December(Deyr) rains in the Horn of Africa resulted in 200% of pre-war average harvest – famine largely over



• Recent climate conditions and trends• Current and forecast state of key climate drivers

• Climate outlook


La Niña 2010 to 2012

Sea surface temperature difference from average

Southern Oscillation Index

La Niña

- 8 ▼

+8 ▲

El NiñoOctober 2010November 2010December 2010January 2011February 2011March 2011April 2011May 2011June 2011July 2011August 2011September 2011October 2011November 2011December 2011January 2012

2011

2012


La Niña – a rapid end

Sea surface temperature difference from normal 1 January 2012

Sea surface temperature difference from normal 16 February 2012

???

Deep ocean temperature difference from normal


El Niño

La Niña

Pacific Ocean – long range forecast

• La Niña conditions are in decline, with the forecast to transition towards neutral during autumn

• Some models quicker, some slower – consensus March–May

POAMA forecast

bom.gov.au/climate/enso

El Niño

- 0.8 ▼

+0.8 ▲

La Niña


Will La Niña impacts cease rapidly?

January 2012January 2011

Sea surface temperature differences Sea surface temperature differences from normal in the Australian region • Warm ocean temperatures remain around Australia’s coasts

• Currently in a ‘break’ period with the Australian monsoon

• Expect another active phase in 2–3 weeks time – possibly mid–late March

• February and March are the peak months of the Australian Tropical Cyclone season



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


Closing the loop – first half of the wet season

www.bom.gov.au/climate/aheadSeasonal outlook for November 2011 – January 2012Model outlooks for Nov 2011–Jan 2012 (Oct 2011)

Our thoughts back in October…

• Moderate to high level of confidence rainfall will be above median in southern Queensland and New South Wales

• At least moderate confidence that Queensland rainfall will be lower than in the same period in 2010–11, although some locations may experience comparable or even greater rainfall(Queensland Nov–Jan 2011: 498 mm – Nov–Jan 2012: 315 mm)


How did the models go picking the La Niña re-emergence?

July 2011 August 2011 September 2011

• Observed values

• Both physics-based ‘dynamical’ models and history-based ‘statistical’ models under-forecast the La Niña prior its October start

• However did indicate conditions would remain on ‘cool’ side


Rainfall outlook for March–May

Chance of above median rainfallHistorical accuracy Simple multi-model outlook


Minimum temperatureMaximum temperatureMaximum temperature

Temperature outlook for March–May


But… forecasting on a trend

2011 – below average

Autumn trend in high pressure systems 1970–2009

More ‘Highs’…

www.bom.gov.au/climate/change/

Autumn trend in high pressure Autumn trend in high pressure systems 1970–2009

MoreMore ‘Highs’‘Highs’…‘Highs’…‘Highs’


Key points

1 . La Niña is passing its peak in the Pacific, and may decline quickly

2. Still potential for strong wet season rains; another monsoonal burst forecast

3. The summer so far has been wet, but less so than for 2010–2011

4. March–May outlook: wetter inland and northern areas of east Australia

5. Neutral conditions are arguably the long range outlook, but skill low at this time of year


Questions?


Hydrologic conditions and outlook

Neil PlummerAssistant Director Climate Information Services



• Queensland and New South Wales flooding 2012• Storage and catchment conditions• Streamflow forecasts for February to April 2012• Dynamic seasonal streamflow forecasting report published



• Queensland and New South Wales flooding 2012

• Storage and catchment conditions• Streamflow forecasts for February to April 2012• Dynamic seasonal streamflow forecasting report published


Queensland and New South Wales flooding 2012

2012 rainfall to date Flood Peaks 23 Jan to 9 Feb 2012Rainfall week ending 3 Feb 2012


Queensland and New South Wales flooding 2012

Flooded rivers and severely affected towns

Enhanced satellite image of floods near Queensland/New South Wales border 9 February 2012

Processed by BoM from Terra/Aqua satellite operated by NASA


Towns affected by flooding

St George – 8 February 2012Department of Environment and Resource Management (DERM)

Charleville levee – Saturday 4 Februaryposted by ‘7_Cannon’ on Twitter


Recent flooding not as widespread as in 2011

January 2011 January 2012 February 2012January 2012 February 2012



• Queensland and New South Wales flooding 2012• Storage and catchment conditions

• Streamflow forecasts for February to April 2012• Dynamic seasonal streamflow forecasting report published


Latest storage levels

0 – 50

51-75

76-100

100 +

Water storages % full

Major storage levels across New South Wales and VictoriaStorage levels across AustraliaStorage levels across Australia


Water storage levels – current status

water.bom.gov.au


Water storage levels

water.bom.gov.au

Dartmouth storage levels Hume storage levels Lake Eildon storage levels


January catchment rainfall and streamflows

Southern New South Wales streamflow terciles

Rainfall Victorian streamflow terciles Northern New South Wales streamflow terciles

High flowNear median flowLow flow


VictoriaMonthly Streamflow ObservationsFor January 2012



Northern New South WalesMonthly Streamflow Observationsfor January 2012



Southern New South WalesMonthly Streamflow Observationsfor January 2012


Soil moisture

Lower layer soil moisture Upper layer soil moisture



• Queensland and New South Wales flooding 2012• Storage and catchment conditions• Streamflow forecasts for February to April 2012

• Dynamic seasonal streamflow forecasting report published


How have the forecasts been going?

November 2011 to January 2012

• Mostly moderate to high skill

• 20 hits 15 misses by 1 1 miss by 2

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 medianflow

Highflow

Sorted Historical Streamflow Record

Observed streamflow

Low flow

Near medianflow

Highflow

Rank/Year

Str

ea

mfl

ow

November to January forecasts


Near median or high flows more likely in Victoria

Victoria

Tambo River at Swifts Creek


High flows more likely in southern New South Wales

Southern New South WalesGoobarragandra River at Lacmalac


High flows more likely in northern New South Wales

Northern New South WalesHalls Creek at Bingara

Jan 2004

Jan 1984

Jan 2012



• Queensland and New South Wales flooding 2012• Storage and catchment conditions• Streamflow forecasts for February to April 2012• Dynamic seasonal streamflow forecasting report published


Dynamic seasonal streamflow forecasting report

• Blending dynamic and statistical SSF forecasts could improve accuracy and reliability

• Dynamic approach could deliver accurate & reliable monthly as well as seasonal forecasts

• Available from www.bom.gov.au/water/about/publications/document/dynamic_ seasonal_streamflow_forecasting.pdf


Key points

• Widespread flooding in Queensland and northern New South Wales, including large areas of major flooding, since 23 January 2012

• Generally near median to high streamflows at Victorian sites and high flows at NSW sites in January

• Near median or high flows forecast for February–April 2012

• Dynamic seasonal streamflow forecasting report published


Questions


Thank you

• The Seasonal Climate Outlook was publicly released yesterday so there is no embargo on this material

• Next briefing proposed for Thursday, 22 March 2012

• Please join us for a light lunch

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