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Bureau of Meteorology www.bom.gov.au National Climate and Water Briefing 29 September 2015

Sunrise, Canberra (jumapics) National Climate and Water Briefing

50th briefing


Welcome

Dr Rob Vertessy

Director


Climate and hydrological

conditions and outlook

Perry Wiles

Manager, Climate Liaison

Photo: Perry Wiles


Recent conditions • Recent conditions

• Climate influences

• Rainfall, temperature and streamflow outlooks


A cold winter?

Photo: Josie Carter

'Bitter cold snap!'

'Australia’s sunshine

state covered in snow'

'Icy cold front to hit

much of Australia'


Temperature

Winter 2015

Maximum temperature deciles Minimum temperature deciles

Maximum temperature

• Equal-eighth warmest winter on record

• 0.83 ºC above average

Minimum temperature


Mean Temperature

• Ninth warmest on record



-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mean t

em

pera

ture

anom

aly

(°C

)

Year-to-date temperature scenarios for Australia

2015

How is Australia

tracking?

Scenarios (September–December 2015)

Rank

Previous highest

September–December 5th

Average since 2000 11th

Current anomaly

1981-2010 average 14th

POAMA forecast 16th


Previous lowest

September–December 54th

2013

1917

2015


-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mean

tem

pera

ture

an

om

aly

(°C

)

Global year-to-date temperature scenarios

2015

How is the

globe tracking?

Scenarios (September–December 2015)

Rank

Previous highest

September–December 1st

Current anomaly 1st

Average since 2000 1st

1981-2010 average 2nd


Previous lowest

September–December 21st

2014

1908

2015


Rainfall deciles, winter 2015

Rainfall

Winter 2015

National 53.6 mm 16% below average

New South Wales 125.2 mm 8% above average

Queensland 38.1 mm 26% below average

Victoria 152.8 mm 25% below average

Southwest Western

Australia 2nd lowest on record 34% below average


Rainfall deficiencies

July 2014 – August 2015 October 2012 – August 2015


• Ski resorts reported late start to the snow

• Overall totals below long-term average

• Several low-level snow falls

• Winter 2015 climate updates, see

www.bom.gov.au/climate/updates/

Snow season 2015

Photo: Bill Shrapnel, 16 July 2015, Orange, NSW

Decadal snow depth at Spencer's Creek

Snow accumulation at Mount Hotham


Rainfall deciles Effective rainfall

August rainfall

Australia

• 11% below average

Murray–Darling Basin

• 23% below average


Mid-layer soil moisture (10-100 cm) Observed streamflow

Soil moisture and

observed streamflow

August 2015

Australian Water Resource Assessment Landscape

(AWRA-L) model schematic


Water storage levels

Change from last year

As at 18 September 2015


Climate influences • Recent conditions




• Also known as Antarctic Oscillation

• Mainly affects rainfall in southern

Australia

• Characterised by north–south

movement of westerlies

• Monitored by the SAM index—positive

and negative phases

Positive SAM Negative SAM

Southern Annular Mode

(SAM)


Positive SAM, average conditions

Southern Annular Mode

(SAM)

-1.5

-1

-0.5

0

0.5

1

1.5

2

Ja

n

Feb

Ma

r

Apr

Ma

y

Ju

n

Ju

l

Aug

Sep

Oct

Nov

Dec

Ja

n

Feb

Ma

r

Apr

Ma

y

Ju

n

Ju

l

Aug

2014 2015

Monthly SAM index (NOAA)

Rainfall deciles, winter 2015

Spring Summer

Winter Autumn


El Niño Ocean

NINO3.4 recent values

• Latest monthly: +1.87 (August)

• Latest weekly: +2.03 (20 Sept)


Three-month cloud patterns 23 June – 20 September 2015

30-day moving Southern Oscillation Index January 2013 – 20 September 2015

El Niño Atmosphere


NINO3.4 forecasts from eight international climate models

El Niño Model outlooks

October February December


Sea surface temperature anomalies, week ending 20 September 2015

2015

Indian Ocean


Outlooks • Recent conditions




Rainfall outlook

October–December 2015

Chance of exceeding median rainfall

October–December


October


November


Rainfall outlook



October–December


Outlook comparison

1997 vs 2015

Probability of above median rainfall


Probability of above median rainfall


2015 1997

August sea surface temperature anomalies

2015 1997

Rainfall deciles October–December 1997


Temperature outlook


Chance of exceeding median maximum temperature

October–December

Chance of exceeding median minimum temperature

October–December


• Low-flow at 158 locations

• Near-median flow at 48 locations

• High flow at 21 locations

• Generally moderate to high model skill

Forecast skill Most likely forecast outcome

Seasonal streamflow

forecast

Spring 2015


In summary

• El Niño continues to strengthen; positive Indian Ocean Dipole likely

• Record warm Indian Ocean influencing rainfall

• October–December outlook:

• Wetter conditions more likely in centre and south; dry in far southeast

• Warmer days more likely in south and east

• Low streamflows forecast at most sites across Australia through spring


Thank you

Questions?

Perry Wiles

Manager, Climate Liaison


Severe weather

2015–2016

Tracey Malmborg

Senior Meteorologist

Note: You can use a photo

suited to your topic – simply

delete this image then

replace with your own


Severe weather

• Seasonal bushfire assessment

• Tropical cyclone outlook

• Severe thunderstorms

• Flood risk

• Heatwaves


Fire weather service

Cooperation between Bureau of Meteorology

and fire authorities


Seasonal bushfire

assessment

Considerations for assessment

• Current fuel loads

• Soil moisture levels

• Long term rainfall deficits

• 3 month climate outlooks


New South Wales

Fuel dryness

September rainfall to date (update) 'Fine' fuel dryness, Tuesday 22 September

• Fine and heavy fuels drying out in north

and west

• Recent rainfall has reduced drought factors

in northeastern New South Wales

• Recent rainfall has delayed hazard

reduction burns in east


Tropical cyclones

2014–2015 tropical cyclone season observations

Last year:

• below-average number

of tropical cyclones (8)

• average number of

landfalls (4)

• all tropical cyclones

reached category 3 or

above (except Raquel)

Raquel 30 June-1July


Tropical cyclone

outlook

Preliminary

Australian seasonal average:

• 11 tropical cyclones

• 4 landfalls

Preliminary outlook for 2015–16

• fewer than average

cyclones expected

• first coastal crossing likely

in late December to

mid-January

• official outlook released

next month


Severe

thunderstorms

Severe thunderstorms

• Large hail (2cm diameter)

• Damaging wind gusts (90 km/h)

• Tornadoes

• Heavy rain that can lead to

flash flooding


Heatwaves

Pilot heatwave forecast, 12 January 2014 Observed maximum temperatures, 12–18 January 2014

• Considers local climatology

• Intensity related to maximum

and minimum temperature

forecasts vs past 30 days


• Major widespread flooding less likely

during El Niño periods

• Localised floods can occur in any

season with significant weather events,

regardless of catchment conditions and

soil moisture

Flood risk

Fairbairn Dam, Queensland,

May 2011

Flash flooding, Caboolture May 2015

picture from Queensland Fire and Rescue


In summary

• Fewer than average tropical

cyclones expected overall

• Official outlook released

next month

• Above-average temperatures

likely

• Elevated risk of heatwaves

• Typical active thunderstorm

season expected

• Less likely to see

widespread flooding

• Elevated risk

(El Niño climate driver)

• Above-average fire season:

southeastern Australia and

southwest Western Australia

Tropical cyclones Heatwaves Bushfires Floods and storms

TC Lam and Marcia, 20 Feb 15, source: NASA EOSDIS


Thank you

Questions?

Tracey Malmborg

Senior Meteorologist


Next briefing

Thursday, 29 October 2015 Clare, South Australia (iStock – Ben Goode)

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