Eight days out from the 21 May 2022 federal general election and much of the NSW Northern Rivers region is on flood watch again

Australian Bureau of Meteorology (BOM):

Flood Watch for the Northern Rivers and Central West

Issued at 12:21 pm EST on Thursday 12 May 2022

Flood Watch Number: 3

MINOR FLOODING POSSIBLE IN THE NORTHERN RIVERS AND CENTRAL WEST FROM THURSDAY

A trough over western inland New South Wales will generate further moderate to heavy rain in many areas of the Central West on Thursday. This may cause minor flooding along the Castlereagh, Macquarie and Bell Rivers from Thursday night.

* Reissue to include Castlereagh *

River level rises have been observed from recent moderate rainfall in the Northern Rivers. Further moderate showers expected on Thursday may see river levels rise to minor flood levels.

Renewed minor flooding is also possible along the Bogan River where a flood warning is current.

The Bureau is continuing to monitor the situation and will issue further catchment specific warnings if and when required.

Catchment soil moisture is average.

The weather system is expected to cause flooding for the catchments listed. Flood Classes (minor, moderate, major) are only defined for catchments where the Bureau provides a flood warning service.

Catchments likely to be affected include:

Tweed and Rouse Rivers - minor flooding 

Brunswick River and Marshalls Creek - minor flooding

Wilsons River - minor flooding

Richmond River - minor flooding

Castlereagh River - minor flooding

Orange, Molong and Bell River - minor flooding

Turon and Macquarie Rivers to Burrendong Dam - minor flooding

Macquarie River d/s Burrendong Dam - minor flooding

Flood warnings are current for the Culgoa, Bokhara, Bogan, Paroo and Warrego Rivers.

For the latest flood and weather warnings see www.bom.gov.au/nsw/warnings/

For the latest rainfall and weather forecasts see www.bom.gov.au/australia/meteye/

For the latest rainfall and river level information see www.bom.gov.au/nsw/flood

 [my yellow highlighting]

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There is a chance of above median rainfall across much of the continent from 14 May 2022 to September 2022.

According to BOM long range forecasting there is also a 50-60% chance of the Page and Richmond electorates in the Northern Rivers region being “unusually wet” between 14 to 27 May 2022.

Stream Flow Forecast

Click on image to enlarge

Climate outlook overview

Issued: 5 May 2022

Winter (June to August) rainfall is likely to be above median for most of Australia, except south-western Australia, the south-east coast, and southern Tasmania which have roughly equal chances of being above or below median.

June to August maximum temperatures are likely to be above median for northern, south-western, and south-eastern parts of Australia, but below median for broad areas of inland southern and central Australia.

Minimum temperatures for June to August are very likely to be warmer than median across almost all of Australia.

The weakening La Niña, the chance of a negative Indian Ocean Dipole, and other localised drivers are likely to be influencing this outlook.

Latest Climate Driver Update, 10 May 2022:

La Niña maintains strength

The 2021–22 La Niña event continues in the tropical Pacific, with little change in strength in the past few weeks.

Several indicators of La Niña, including tropical Pacific sea surface temperatures, cloudiness near the Date Line, and the Southern Oscillation Index (SOI), have maintained or slightly increased their strength over the past fortnight. However, beneath the surface of the tropical Pacific, waters have warmed closer to neutral El Niño–Southern Oscillation (ENSO) levels.

Most climate models surveyed by the Bureau indicate a return to neutral ENSO by the early southern hemisphere winter. Only one of seven models continues La Niña conditions through the southern winter. La Niña conditions increase the chances of above average rainfall for much of eastern Australia, while neutral ENSO has little influence on rainfall patterns.

The Indian Ocean Dipole (IOD) is neutral. All climate model outlooks surveyed suggest a negative IOD may develop in the coming months. While model outlooks have low accuracy at this time of year and hence some caution should be taken with IOD outlooks beyond May, there is strong forecast consistency across international models. A negative IOD increases the chances of above average winter–spring rainfall for much of Australia. It also increases the chances of warmer days and nights for northern Australia.

The Southern Annular Mode (SAM) index is currently positive and is forecast to remain positive for the coming four weeks. During autumn SAM typically has a weaker influence on Australian rainfall, but as we approach winter, positive SAM often has a drying influence for parts of south-west and south-east Australia.

The Madden–Julian Oscillation (MJO) has recently strengthened in the western Indian Ocean. Most climate models indicate the MJO will briefly weaken, and then re-strengthen again later this week in the Maritime Continent or western Pacific region. Should the MJO re-strength in the Maritime Continent region, it can enhance rainfall in north-eastern Australia. It also typically increases cloudiness to Australia's north.

Climate change continues to influence Australian and global climate. Australia's climate has warmed by around 1.47 °C for the 1910–2020 period. Southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades. There has also been a trend towards a greater proportion of rainfall from high intensity short duration rainfall events, especially across northern Australia. [my yellow highlighting]

NSW predicted rainfall over April, May and June 2022

It would appear there is some likelihood that the next three calendar months will see temperatures rise above median and a 60 per cent chance of an increase in median rainfall across New South Wales generally.

With the predicted above median rainfall occurring inland as far as Tibooburra & Broken Hill and along the length of the coastal zone. 

The Northern NSW section of this coast zone - from Clarence Valley  to Tweed Shire and inland as far as Lismore City - having a 60 to 74 per cent chance of exceeding median rainfall.

Brief Outline

Australian Bureau of Meteorology (BOM), retrieved 14 March 2022:

Climate outlook overview

Issued: 10 March 2022

April to June rainfall is likely to be above median for most of northern and eastern Australia, with small areas of south-west WA and western Tasmania likely to be below median. Elsewhere, there are roughly equal chances of above or below median rainfall.

April to June maximum temperatures are likely to be above median for western, northern and south-eastern parts of Australia. Elsewhere, there are roughly equal chances of warmer or cooler days.

Minimum temperatures for April to June are likely to be warmer than median across virtually all of Australia.

Climate influences include the weakening La Niña in the Pacific Ocean.

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La Niña remains active in the tropical Pacific. Outlooks indicate the La Niña is likely to end around mid-autumn 2022, with a return to neutral El Niño–Southern Oscillation conditions. While this La Niña event is weakening, it is expected to continue to contribute to the wetter than median outlooks for parts of eastern Australia.

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BOM: Median rainfall April-June (1981-2018) 

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Wetter April to June likely for northern and eastern Australia

Issued: 10 March 2022

April to June rainfall is likely to be above median for most of the NT, Queensland, south-east SA, and most of NSW (chance of exceeding median is greater than 60%). Some small areas of south-west WA and western Tasmania are likely to be below median (chance of exceeding median is less than 40%). Elsewhere, there are roughly equal chances of above or below median rainfall (chance of exceeding the median is close to 50%).

There is an increased chance of unusually high rainfall (in the top 20% of historical records) for April to June across the northern half of the NT, northern and western Queensland and small areas of western and coastal NSW (1.5 to 2.5 times the usual chance). However, it should be noted that seasonal rainfall at this time of the year is starting to decrease, so unusually high rainfall for these areas isn't as high as recent months.

While the April outlook reflects the three-month outlook, the May outlook suggests below median rainfall is likely for south-western Australia, and western Tasmania, and only a small part of central Queensland is likely to be above median.

Past accuracy for April to June rainfall is moderate to high for most areas of Australia, with low to very low accuracy across much of eastern WA, northern and western SA, the central NT, western Victoria and southern Tasmania.

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Warmer April to June days and nights for most areas

Issued: 10 March 2022

April to June maximum temperatures are likely to be above median for most of WA, the northern and central NT, Queensland, northern and southern NSW, south-east SA, Victoria, and Tasmania (greater than 60% chance). Elsewhere, there are roughly equal chances of warmer or cooler days (chance of exceeding the median is close to 50%).

There is an increased chance of unusually high maximum temperatures (in the top 20% of historical records) for April to June over most of WA, the northern and central NT, most of Queensland except the far south, most of Victoria, and Tasmania (1.5 to 4.0 times the usual chance), with the highest chances in the tropical north, and Tasmania.

Minimum temperatures for April to June are likely to be warmer than median almost Australia wide (chances are greater than 60%), with much of northern and eastern Australia very likely (chances are greater than 80%).

There is an increased chance of unusually high minimum temperatures (in the top 20% of historical records) for April to June over most of Australia except much of southern WA and western SA (1.5 to 4.0 times the usual chance). The highest likelihoods are across far northern Australia and Tasmania.

Past accuracy for April to June maximum temperatures is high to very high for almost all of Australia, with moderate accuracy in a band stretching through central WA and across most of SA. For minimum temperatures, accuracy is high to very high across northern Australia, grading to low to very low accuracy across southern parts of the mainland. Tasmania has moderate accuracy in the south, with low accuracy in the north.

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Historical median and mean rainfall Lismore, Ballina, and Grafton NSW for April, May and June.

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La Niña's arrival in the tropical Pacific may herald high flow river levels on the NSW coast during December 2021

Australian Bureau of Meteorology (BOM):

Climate outlook overview, 18 November 2021:

• December to February rainfall is likely to be above median for the eastern half of the eastern States, with highest chances along eastern Queensland.

• There is an increased chance of unusually high rainfall (in the top 20% of historical records) for December to February for parts of the eastern States (1.5 to 2.5 times the usual chance).

• December to February maximum temperatures are likely to be above median for much of northern and western Australia, as well as parts of the south-east. Below median daytime temperatures are likely for eastern NSW.

• Minimum temperatures for December to February are likely to be warmer than median for most of Australia, with southern WA and western SA having roughly equal chances of warmer or cooler than median nights.

• The developing La Niña conditions in the Pacific Ocean, and the La Niña (SAM) phase are likely influencing the above median rainfall outlooks.

 Climate Driver Update, 23 November 2021:

La Niña established in the tropical Pacific

La Niña has become established in the tropical Pacific. The Bureau's ENSO Outlook has been raised to LA NIÑA. Climate models suggest this La Niña will be short-lived, persisting until the late southern hemisphere summer or early autumn 2022. La Niña events increase the chance of above average rainfall across much of northern and eastern Australia during summer.

Several indicators of the El Niño–Southern Oscillation (ENSO) now show clear La Niña patterns. Sea surface temperatures in the tropical Pacific are close to La Niña thresholds, with climate model outlooks expecting them to cool further. In the atmosphere, cloud and wind patterns are typical of La Niña, indicating the atmosphere is now responding to, and reinforcing, the changes observed in the ocean.

The negative Indian Ocean Dipole (IOD) is approaching its end, with oceanic index values in the neutral range. However, cloud and wind patterns across the eastern Indian Ocean suggest some IOD influence remains. All models indicate the IOD will remain neutral for the coming months, consistent with its typical seasonal cycle. A negative IOD increases the chances of above-average spring rainfall for much of southern and eastern Australia.

The Madden–Julian Oscillation (MJO) is currently over the Maritime Continent region at weak to moderate strength. The MJO is forecast to progress eastwards across the Maritime Continent and into the western Pacific over the coming fortnight, increasing the chances of above average rainfall across northern Australia and the Maritime Continent, to Australia's north.

The Southern Annular Mode (SAM) has generally been positive for several weeks. It is forecast to remain at positive levels to the end of the year. A positive SAM during summer typically brings wetter weather to eastern parts of Australia, but drier than average conditions for western Tasmania.

Climate change continues to influence Australian and global climate. Australia's climate has warmed by around 1.44 °C for the 1910–2019 period. Rainfall across northern Australia during its wet season (October–April) has increased since the late 1990s. In recent decades there has been a trend towards a greater proportion of rainfall from high intensity short duration rainfall events, especially across northern Australia.

Latest Bureau Of Meteorology Climate Driver Update, Australian Daily Extreme Temperatures Jan-Aug 2021 & Spring rainfall predictions

Issued 31 August 2021

Tropical Pacific Ocean likely to cool, but remain ENSO-neutral

The El Niño–Southern Oscillation (ENSO) is currently neutral. Sea surface temperatures (SSTs) in the central tropical Pacific Ocean are near average, despite slowly cooling over the past two months. Waters beneath the surface are slightly cooler than average.

While most models indicate SSTs in the central tropical Pacific are likely to continue cooling over the coming months, ENSO-neutral is favoured to persist. Only two of the seven models surveyed suggest SSTs will remain cool for long enough to be considered a La Niña event. This cooling of the tropical Pacific may be contributing to the wetter than median climate outlooks in Australia.

Most climate models predict the negative Indian Ocean Dipole (IOD) event will persist through the southern hemisphere spring, despite current values rising marginally above the −0.4 °C threshold. Stronger-than-usual easterly winds across the tropical eastern Indian Ocean over the last three weeks have weakened the IOD event, however, this is most likely to be temporary. A majority of the five climate models surveyed by the Bureau predict the negative IOD will persist into November. A negative IOD increases the chance of above average winter–spring rainfall for much of southern and eastern Australia.

The Madden–Julian Oscillation (MJO) is currently in the western Indian Ocean, where it has remained since early August. This phase of the MJO typically sees increased cloudiness over the Southeast Asian parts of the Maritime Continent and eastern Indian Ocean, along with enhanced easterly wind anomalies, which may have acted to weaken the negative IOD. Forecasts generally indicate a weak MJO will progress eastwards across the Indian Ocean in the coming week.

The Southern Annular Mode (SAM) index has been positive over the past week and is forecast to remain so for the next fortnight. A positive SAM typically has a drying influence on south-west and south-east Australia during winter, and enhances chances of above average rainfall over much of New South Wales during spring.

Climate change continues to influence Australian and global climate. Australia's climate has warmed by 1.44 ± 0.24 °C over 1910–2019, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades.

Next Climate Driver Update expected on 14 September 2021.Climate Driver

Daily maximum temperature extremes graph for Australia: 1 January to 31 August 2021

Above median spring rainfall likely for eastern two-thirds of Australia

Issued: 26 August 2021

• Rainfall for spring (September to November) is likely to be above median for south-east WA, the NT, SA, Queensland, NSW, Victoria and eastern Tasmania (chance of exceeding median is greater than 60%). Much of the eastern States show a greater than 80% chance, as does eastern parts of the NT and SA. Conversely, parts of western WA and south-west Tasmania are likely to have below median rainfall (chance of exceeding the median is less than 40%).

• The pattern for the months of September and October is similar to the spring outlook, though the likelihood of exceeding the median rainfall is not as high in the eastern two-thirds of the country, and extends further west into eastern WA for September.

• Rainfall for October to December is likely to be above median for the eastern half of Australia, and below median for north-west WA.

• Past accuracy (Opens in new window) for September to November rainfall is high to very high for most of the eastern two-thirds of Australia, with moderate accuracy for central and eastern Victoria, most of WA and the central NT shifting to low accuracy for central areas of WA.

BOM September 2021 rainfall outlook: Taree to the NSW-Qld border

Quote of the Week

“Climate change continues to influence Australian and global climate. Australia's climate has warmed by 1.44 ± 0.24 °C over 1910–2019, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades.” [Australian Bureau of Meteorology, “Climate Driver Update” , Issued 22 June 2021]

The El Niño–Southern Oscillation (ENSO) is expected to remain in neutral phase at least until October 2021

Australian Bureau of Meteorology, Climate Driver Update, 11 May 2021:

Southern Annular Mode positive; El Niño–Southern Oscillation neutral

The El Niño–Southern Oscillation (ENSO) continues at neutral levels. Climate model outlooks currently indicate this neutral phase will last at least until October.

Oceanic indicators of ENSO persist at neutral levels, with Pacific sea surface temperatures close to the long-term average across most of the equatorial region. Beneath the surface, temperatures are near-average, with slightly warmer than average waters across much of the sub-surface. Atmospheric indicators such as the Southern Oscillation Index (SOI) and cloud patterns are also close to average. Trade winds have been stronger than average in the far west, but near average elsewhere.

The Madden–Julian Oscillation (MJO) is over the Indian Ocean region. It is forecast to move eastwards across Australian longitudes over the coming fortnight. When the MJO is active over the eastern Indian Ocean and Australian longitudes at this time of year, above average rainfall is more likely over the Maritime Continent to Australia's north. Additionally, it typically acts to strengthen easterly winds on Queensland’s tropical east coast and increase temperatures across tropical Australia.

The Southern Annular Mode (SAM) has been positive for the past week. It is expected to remain positive for the coming fortnight. SAM typically has little influence on Australian rainfall during autumn, but may have a drying influence for parts of south-west and south-east Australia over the coming fortnight.

The Indian Ocean Dipole (IOD) is currently neutral. Climate model outlooks suggest the IOD is most likely to remain neutral during the first half of winter. Three of the five models indicate negative IOD thresholds may be reached during winter or spring. The accuracy of IOD forecasts made during autumn is generally lower than at other times of the year, but improves in winter. A negative IOD increases the chances of above average winter-spring rainfall for much of southern Australia.

Climate change continues to influence Australian and global climate. Australia's climate has warmed by 1.44 ± 0.24 °C over 1910–2019, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades. [my yellow highlighting]

Climate Model Summary for June to October 2021 at:

http://www.bom.gov.au/climate/model-summary/#region=NINO34&tabs=Pacific-Ocean

Next update expected on 25 May 2021

It appears that temperatures, winds, convection (rising air), and rainfall across the tropical Pacific may remain near their long-term averages, but temperatures in Australia's north may be warmer than usual and rainfall across much of southern Australia may increase from June to October.

In Australia this summer "heatwaves may not reach the extreme temperatures of recent years, but may be longer duration and more humid, which can still have a significant impact on human health"

Heatwave Situation for Monday, Tuesday, & Wednesday (3 days starting 30/11/2020)

Areas of low-intensity heatwave experienced through northern WA, central NT, most of QLD, northeastern SA and northern NSW. Areas of severe heatwave experienced in southern and western QLD and inland northern NSW. An area of extreme heatwave experienced in south central QLD and over the NSW border.

Clarence Valley Independent, 1 December 2020: 

Australia can expect a wetter than normal summer, but bush and grass fires cannot be ruled out completely, according to the Bureau of Meteorology’s Summer Climate Outlook released today. 

The outlook for summer has been issued as Australia continues to experience an active La Niña event which is expected to remain until at least the start of autumn. 

The Bureau’s Head of Operational Climate Services Dr Andrew Watkins said this means large parts of eastern Australia have an increased risk of flooding. “While the last three weeks have been dry in many parts of the country – due in part to unfavourable tropical weather patterns – it does not signal a weakening of La Niña. 

“Our climate outlook is the opposite of what we experienced last year in Australia. This summer, New South Wales, Victoria and Queensland are expected to see above average rainfall, meaning we face an increased risk of widespread floods. 

Dr Watkins said that while the risk of bushfires isn’t as high as last summer, fires will occur. 

“There’s a great chance of grass fires in some areas as recent rain and warm weather have led to vigorous vegetation growth. South eastern Australia is one of the most fire-prone regions in the world. 

Even short periods of hot and dry weather increase the risk of fire in summer.” Dr Watkins said the outlook was also a reminder for communities to be prepared for heatwaves over the coming months. 

“Every summer we see heatwaves across southern Australia. This summer heatwaves may not reach the extreme temperatures of recent years, but may be longer duration and more humid, which can still have a significant impact on human health. 

“Daytime temperatures in summer are likely to be near average, but there will be periods of high heat combined with milder periods. 

“It’s important to keep up to date with the Bureau’s heatwave service.”.....

The utltra-absurd among the many politically absurd One Nation members is at it again.......

The Canberra Times, 21 October 2019:

The Bureau of Meteorology has again been accused by a One Nation senator of changing its data so it fits in with the narrative of climate change extremists.

The head of Australia's weather agency has fended off questions from One Nation senator Malcolm Roberts suggesting the bureau has changed data to fit a climate change narrative.

Senator Roberts has taken issue with a graph which he says can no longer be accessed on the Bureau of Meteorology's website, which had outlined the number of "very hot days" from 1920 to 2015.

"Firstly, I reject the premise of your overarching question," he said.

"The Bureau of Meteorology simply reports on the data which it observes.

"Integrity of our data is of the highest order and I stand absolutely, 100 per cent behind it."

It is possible Mr. Roberts has seen a graph based on BOM data but created by another agency or individual. A number of these graphs do exist on the Internet.

Grafton experienced more hot days in past 30 years

Grafton's average monthly rainfall 1959 to 2018:

Grafton's average water balance after the evaporation rate is accounted for:

Graphs from http://www.bom.gov.au/climate/climate-guides/

It should be noted that longterm averages are a crude measurement tool and do not always reflect conditions experienced in specific years.