A trough in the north is causing patchy rain in the NT. Southerly winds are spreading north along the eastern seaboard, bringing a few showers. A high is causing wind to ease & showers to clear in WA's south. Highs are keeping elsewhere generally dry.
Weather in Business
Today, 5:38AM UTC
Temperature inversions explained
There’s an invisible layer of air in the sky that can have significant impacts on communities and industries across Australia. This unseen phenomenon is called a temperature inversion and you could be standing in one right now without even realising it. What is a temperature inversion? The air near the ground is usually warmer than the air sitting above it, with the atmosphere becoming cooler with height until you reach the stratosphere. A temperature inversion occurs when a section of this temperature profile is inverted, causing relatively cooler air to sit beneath a layer of warmer air in the lowest levels of the atmosphere. One of the most common ways for a temperature inversion to develop is by cooling of the air near the ground. This typically happens on clear and calm nights through a process called radiative cooling, which involves the ground getting colder at night when heat radiates into space. This nocturnal cooling, which happens more efficiently on clear and calm nights, causes the layer of air sitting just above the ground to become cooler as well. Over time, the air near the ground becomes sufficiently cooler than the air above it, forming a temperature inversion. Why do inversions matter? A well-formed temperature inversion can significantly influence weather conditions near the ground. They can affect human health, agriculture, mining operations, noise and smoke propagation, and sometimes cause mirages. Frost and fog Two of the most common side-effects of ground-based temperature inversions are frost and fog, which form when the ground or air temperature gets sufficiently cold enough for condensation or deposition to occur. The lingering cold and calm conditions during a temperature inversion can also cause frost and fog to become widespread and long-lasting. Mining and agriculture Mines, farmers and other large-scale outdoor operations also monitor for the presence of temperature inversions because they influence the propagation of noise and pesticides. Sound and airborne particles can become trapped beneath a temperature inversion, allowing them to travel long distances near the ground instead of mixing up into the atmosphere. Some operations like mine blasting and crop spraying cannot be carried out safely until an inversion has broken down. Temperature inversion setting in. Hope the sprayers are parked. pic.twitter.com/eCrdIm0h8T — Ryan Benjamins (@RyanBenjamins) June 24, 2022 Pollution Airborne pollution can become trapped near the ground when a temperature inversion is in place, which can have a detrimental effect on human health, particularly for people suffering from respiratory conditions. This can include emissions from industrial activities, smoke from bushfires and vehicle exhaust. On rare occasions, these pollutants can be seen trapped in the sky, giving us a brief glimpse of an otherwise invisible temperature inversion. Mirages One of the most awe-inspiring effects of temperature inversions are mirages. While rare, there have been well-documented examples of objects appearing to float in the air due to the way an inversion bends light in the atmosphere. One of the more famous examples of this is the Fata Morgana, which can cause ships and mountain ranges to appear to float above the horizon. "Hovering ship" this is what is known as a looming superior mirage (mostly seen in the arctic) caused by light being refracted by a big temperature inversion between the cold sea and warm air just above it.....wierd though !! pic.twitter.com/SxfCsxqYvq — weatherbraine (@weatherbraine) March 4, 2021
Today, 1:24AM UTC
Minus 6 for Canberra on night of widespread frosts
It’s been a super chilly one overnight in large parts of Australia, with cold, dry, relatively still air across much of the country creating perfect conditions for widespread frosts. Indeed, sub-zero temperatures were recorded in seven of the eight Australian states and territories. Canberra had its lowest temperature of the year, with a minimum of -6°C just before 7 am. The year’s previous coldest morning was -4.5°C on June 15, and for those who love records, the national capital’s coldest recorded temp was -10°C in July 1971. Australia’s coldest overnight temps were all in the mountains and tablelands in southern NSW near Canberra, with the mercury bottoming out at -8.1°C at Cooma Airport. But even low-lying NSW towns in the state’s north and west experienced an extreme chill overnight, with a low of –3.1°C at Cobar, near Bourke (the coldest on record there was -6.7°C in July 1997). Image: Frosty start in Mandurama, NSW on Tuesday morning. Source: @kangarooflatlavenderfarm / Instagram The lowest overnight minimum by state was: Victoria Mt Hotham -6.4°C New South Wales Cooma Airport -8.1°C ACT Canberra Airport -6°C Queensland Applethorpe -2.6°C South Australia Gluepot -4.0°C Tasmania Liawenee -2.5°C Western Australia Collie East -0.1 -2.5°C Northern Territory Yulara 5.1°C It’s worth noting that while the Northern Territory was the only state or territory where no locations dropped below freezing, sub-zero temps happen quite a lot, and we actually wrote a story about how cold (both max and min) temperatures can get in the NT last week. Meanwhile it looks like another cold and frosty one for a good chunk of inland Australia tonight, before overnight temps start to moderate later in the week with the influx of moist air from the east.
27 Jun 2022, 5:46AM UTC
Rain on the way for northern and eastern Australia
Unseasonably heavy rain will spread over parts of the NT and QLD later this week, with wet weather also set to return to Australia’s east coast. Northern Australia is in the middle of its dry season, a largely rainless six-month period that runs from May to October. The map below shows that most of northwest QLD and the northern half of the NT usually receive less than 5mm of rain during all of July. Image: Long-term average rainfall for July. Source: Bureau of Meteorology This week, however, a stream of tropical moisture is going produce rain over a broad area of the NT and QLD, possibly delivering several months’ worth of dry-season rainfall in some areas. A few showers will develop over the NT and far west QLD on Tuesday and Wednesday as a cloudband starts to build across northern Australia. Rain will become heavier and more widespread between Thursday and Saturday as the cloudband slowly drifts further east. The injection of tropical moisture provided by this large cloudband will also help produce rain over a broad area of eastern Australia from Friday into the weekend, possibly persisting into the start of next week as well. There are early signs that some of this rain could become heavy enough to causef flooding as a coastal trough deepens early next week. The two maps below show how much rain two different forecast models are predicting this week, from Monday to Sunday. Image: Forecast accumulated rain during the 7 days ending on Sunday, July 3. This rain event could cause flooding in parts of the NT, QLD and eastern NSW, including areas that are normally dry at this time of year. Be sure to check the latest forecasts and warnings in your area.
Weather in Business
21 Jun 2022, 3:53AM UTC
La Nina floods make NSW ports too fresh for ships
La Niña has had a surprising impact on shipping operations in NSW this year, with increased freshwater outflows from flooded rivers affecting the behavior of ships entering some ports. Ships entering tidal ports in NSW are affected by local weather conditions, tides and waves, which can all affect a vessel’s ability to enter and operate safely within a port. One of the important things to consider when allowing larger vessels to enter NSW ports is the tide, which needs to be high enough to allow deep drafted vessels to enter, navigate and exit a port safely. This year, the window of time where water levels are high enough for ships to enter some NSW ports has been reduced by enhanced freshwater inflows from heavy rain and flooding. Image: Rainfall between January and May 2022 was in the top 10 percent of historical records for most of eastern NSW, with some areas receiving their highest rainfall on record for this period. Source: Bureau of Meteorology Freshwater is less dense than salt water, which allows ships to sit lower in the water. The prolific flooding seen in parts of eastern NSW earlier this year caused huge injections of freshwater into the coastal zone, which decreased salinity and affected shipping operations. According to Philip Perkins, Meteorologist and Sales Executive of Ports, Offshore and Safety at Weatherzone, "port users and operators at river-based terminals have been impacted by summer and autumn rainfall. “During high river flows water salinity is reduced. This means vessels can behave differently, resulting in elevated risk to vessels even at berth. Even when secured properly, berthed vessels can be impacted by passing traffic in the terminal.’’ In addition to the safety of ships, decreased salinity at river-based terminals can also reduce the window of time where larger vessels can enter these ports. In some cases, this may force ships to wait for the next high tide before entering or departing the port. Fortunately, river levels and discharge rates have now returned to more normal levels in eastern NSW. However, the ongoing influence of La Niña and a developing negative Indian Ocean Dipole increases the risk of more flooding in the months ahead. With the ground still holding a lot of water, any periods of heavy rain this winter and spring are likely to cause flooding, which may have immediate impacts on shipping operations.
17 Jun 2022, 1:24AM UTC
Does winter or summer cause more energy demand?
Australia’s National Electricity Market (NEM) is in the throes of an energy crisis that has partially being driven by an abnormally cold start to winter. But how does energy demand change throughout the year and would this crisis have been worse if it happened in summer? Summer and winter are both challenging seasons for everyone involved in the electrical market. Heatwaves and cool spells both place a significant strain on the electricity system in Australia as they increase the amount of heating or cooling occurring in homes and businesses. Extremely hot or cool temperatures can also impair key electrical infrastructure, which can also play a part in causing electricity outages in both summer and winter. Furthermore, extreme weather events such as bushfires, flooding, lightning, tornadoes and severe storms can all affect electricity networks. Each season has their own unique mix of challenges for Australia’s electricity markets. Summer Heatwaves and extreme high temperatures cause high energy demand through increased air conditioner use during summer. Heatwaves have the greatest impact on the network when they impact multiple states at the same time. Some other common summer impacts include: High temperatures impair the operation of key electrical infrastructure. This can be compounded by high energy demand that often occurs at the same time. Generators, power lines, transformers and other electrical equipment can underperform or fail when temperatures get too hot. Renewable energy infrastructure is also impacted by the heat with solar panels and wind turbines underperforming. During summer, raging bushfires often threaten the electricity network and transmission lines. The Black Summer bushfires during 2019 and 2020 damaged power lines and caused widespread power outages that impacted tens of thousands of households in Australia’s southeast. Dust storms in summer can cause sparking between lines, sometimes initiating more fires and line failures. Winter Cool temperatures also increase energy demand with increased heater use in homes and businesses. Some of the typical winter impacts on the electricity market include: Strong winter winds in southern Australia can damage transmission lines causing black outs or outages. Key electrical infrastructure also underperforms when temperatures get too cold. Is energy demand higher in summer or winter? According to the Australian Energy Market Operator (AEMO), maximum operational demand occurs in summer, driven by cooling loads across most of Australia’s states and territories. However, Tasmania’s peak demand occurs in winter, driven by heavy heater use amid bitterly cold outdoor temperatures. The chart below shows that demand in Victoria has been higher in January (summer) than July (winter) during each of the past ten years. Chart: Highest energy demand (MW) in Victoria during the past 10 years in January and July. Source: AEMO’s Aggregated Price and Demand Data - Historical In AEMO’s 2019 summer readiness report, they stated that weather forecasts are “now the most important input into forecasting of demand and supply of generation for the National Energy Market (NEM)”. Given the intrinsic relationship between temperature and electricity demand, Australia’s warming climate is likely to have an impact on demand and infrastructure in the future.