A moisture-laden trough is generating rain & storms in SA, VIC & NSW's south, some intense. Troughs are also bringing showers to TAS & the NT's south & hot winds to NSW's & QLD's west. Troughs in the north are causing showers & storms, with TC Jasper approaching QLD's north.
Weather in Business
Today, 5:58AM UTC
Heaviest December rain in 75 years soaks parts of SA
A slow-moving rainband has delivered the heaviest December rainfall in decades to parts of South Australia, with strong winds starting to take hold. It was the wettest December day in 75 years in Cleve, with 55mm falling in the gauge to 9am Sunday. Kimba saw 47mm, its heaviest December rain in 61 years. Several locations set new site December records such as: Mount Ive 51.2mm (53-year history) Edithburgh 36.8mm (27-year history) Noarlunga 40.0mm (23-year history) Minlaton 47.8mm (22-year history) For Wudinna in the state’s west, its 48.6mm equalled its site's daily rainfall record set on November 19, 2022, with records since 2000. Image: Observed rainfall in the 24hrs to 4:30pm CDT Sunday On Sunday, rainfall is continuing over western and central parts of SA, with the edge of the rainband affecting Adelaide. While the rain might be easing around Adelaide and eastern parts of SA, the southeasterly winds are starting to pick up. Later this evening, southeasterly winds are expected to gust up to 100km/h, with 85km/h already recorded at Selicks Hill at 4pm this afternoon. Image: Wind gusts expected in the early hours of Monday morning. Winds in red and purple indicate strong winds that may bring down trees and branches. Southeasterly winds can be notoriously damaging for parts of the Mount Lofty Ranges and Adelaide Hills due to the local effects of the hills. When a low-level inversion forms (such as during a cold day and night like Sunday), southeasterly winds get squeezed between the ground and the inversion like a wind-tunnel, amplifying the winds over the region. These damaging winds are known as 'gully winds'. The recent rain further increases the chances of trees and their branches falling overnight, with the softer soils weakening tree roots and making them easier to fall. These trees and limbs can fall on power lines, creating local hazards and large-scale power outages. Please remember to never approach live wires and call the SES on 132 500 to report them. The rainband and low pressure system responsible will linger around for several days yet, but will return to more ‘normal’ warm with showers and thunderstorms type of weather. Plenty of warnings - including flood watches and severe weather warnings - are current, so please visit Weatherzone for the latest information.
09 Dec 2023, 6:17AM UTC
Record December Sydney heat, near-record Adelaide cold
The forecast Saturday scorcher arrived in Sydney, with Sydney Airport recording its hottest December day on record (in records going back to 1929). Sydney Airport's peak of 43.5°C just after 1 pm beat the old mark of 43.2°C which had stood since 1994. Sydney's official weather station at Observatory Hill, near the southern pylon of the Sydney Harbour Bridge, reached exactly 40°C as forecast just before 12:30 pm before the sea breeze kicked in. Several locations in the city's outer west got hotter than Sydney Airport, including the site of Sydney's future second major airport at Badgerys Creek, which reached 44.0°C. Despite the extreme heat in the outer west, as we write this story late on Saturday afternoon, it appears that December heat records in the western half of Sydney have been threatened but not quite broken. Up to 5 pm Saturday: Richmond in the northwest had reached 43.8°C Penrith in the far west had reached 43.9°C Badgerys Creek in the west had reached 44.0°C Holsworthy in the southwest had reached 43.8°C As Weatherzone meteorologist Ben Domensino wrote on Friday, a cool change will flush the heat out of the Sydney Basin late on Saturday, bringing a brief period of relief into next week before another likely hot burst arrives midweek. Meanwhile in Adelaide, it has been a totally different story this Saturday, as unseasonably heavy rain and southerly winds combined to keep temperatures below 16 degrees all the way from 9 am through to 4 pm. Adelaide's coldest December day on record saw a maximum of just 15.4°C back in 1955 It's not yet clear where this Saturday sits in the pecking order of cold December Adelaide days (as official maximums aren’t available until 9 am the following day) but it may well end up being the coldest in 57 years. A total of 22 mm of rain fell in Adelaide from 9 am to 4 pm, on top of 8 mm of overnight rain which was already in the gauge at 9 am this morning - making it the wettest December day in seven years. The loop above shows the constant feed of rain across parts of southern SA in a three-hour loop on Saturday afternoon. Some areas have missed out while some areas in both SA and Victoria have copped a very welcome December drenching. The image below shows the rain observations since 9 am, as well as the areas of heat and cool, in what was a hugely contrasting day of December weather in southeastern Australia.
09 Dec 2023, 3:09AM UTC
Thunderstorm asthma: what is it?
Thunderstorm asthma. A combination of words that you wouldn't usually associate with each other, yet when put together, creates a monstrous phenomenon that can hospitalise hundreds. In southeast Australia, particularly Victoria and New South Wales, this phenomenon usually occurs from October to December, but not every year. As we wrote here, this period is also when some of Australia's strongest storms occur. So, we are in peak thunderstorm asthma season. During this time, grass pollen from pasturelands is released into the air, travelling long distances and into populated areas. Cold air downdraughts from certain types of thunderstorms can initially 'rupture' the pollen from increased internal pressure. These are then concentrated in the 'gust front', or the outflow from the storm, with the pollen then being carried and spread out from the warm air updraught (Figure). Figure: Example of a squall line thunderstorm, which is an ideal setup for thunderstorm asthma events in southeast Australia (Weatherzone, 2023). It's important to know what to look out for when predicting, and then responding to thunderstorm asthma events. On November 24th, 2023, VicEmergency issued a thunderstorm asthma warning, with Mallee and North Central districts receiving high risks, and much of the central districts receiving moderate risks. This was all associated with a high likelihood of severe thunderstorms, mostly about western Victoria, issued by the Bureau of Meteorology on the morning of November 24th. Figure: Thunderstorm forecast for heavy rainfall and damaging wind gusts issued at 10:39am on November 24th for Victoria (Bureau of Meteorology, 2023). Hours later the severe thunderstorm warning was adjusted to include large hailstones. Since hail is associated with a downward motion, there was an implied increase in thunderstorm asthma risk as the gust front will have been much more efficient at concentrating particles with this downdraught. Figure: Severe thunderstorm warning for heavy rainfall and large hailstones issued at 2:43pm on November 24th for western Victoria (Bureau of Meteorology, 2023). Until the end of the year, particularly if you're vulnerable to hay fever or respiratory conditions, it is important to be mindful of such warnings. Keep an eye out for them here. VicEmergency also issues daily thunderstorm asthma risk forecasts that can be viewed here. When these occur, be sure to stay indoors as much as possible, keep windows and doors closed, and for asthmatics, review your asthma action plan.
Weather in Business
22 Nov 2023, 12:22AM UTC
Is Australia a great place for offshore wind farms?
Australia has some of the best offshore wind resources in the world, which are set to be captured by facilities scattered across our vast coastline in several years time. The offshore wind industry is booming internationally, as countries around the globe use it as part of their renewable energy transition. Wind farms are typically placed in windy locations, such as hilltops, but now Australia is looking offshore. According to the Global Wind Energy Council, Australia has the potential to generate 5,000 gigawatts of electricity from offshore wind, which is 100 times the installed capacity of Australia's two largest electricity networks. However, it's likely to be several years before an offshore wind farm becomes operational in Australia. The map below shows that the offshore wind resources in Australia are mostly around southern Australia near cities and industrial hubs and mining. Image: The mean wind speed along our coastline in m/s and the offshore wind resources in Australia, October 2021, Source: NOPSEMA Why go offshore? There are several reasons why offshore wind farms are beneficial sources of energy in Australia, such as strong winds over the ocean, reduction in costs and the size of turbines and farms over water. Strong winds over the ocean Wind speeds across the ocean are consistently stronger than those over land, meaning more wind power can be produced by these offshore facilities. The strongest winds in Australia are typically around coastal regions including western Tas and Vic, the Eyre Peninsula in SA, the southwestern coastline of WA, and the Great Australian Bight. The winds are strongest in these regions due to the passage of cold fronts or low pressure systems and the Roaring Forties. The Roaring Forties are gale force westerly winds that typically blow between the latitudes of 40° and 50° south shown in the image below. These winds gain their power from the planetary–scale circulation as the atmosphere moves hot air from the equator to the poles. Since the planet rotates, these winds are deflected to blow from west to east by the Coriolis Effect. Unlike in the Northern Hemisphere, these winds encounter very little land to slow them down in the Southern Hemisphere, allowing them to blow consistently strongly. Once used regularly by sailors, the power of the roaring forties will be harnessed by offshore wind turbines. Size of turbines and farms While building offshore wind farms is challenging and costly, the size of the wind turbines and farms at sea can be much larger than over land. The size of wind farms and individual turbines over land are restricted in size due to transport and other constraints like land use. The larger the wind turbine, the greater the amount of electricity that can be produced. Cost and technology The technology of offshore wind farms has improved over recent decades which has helped drive the cost of installing the wind farms down. The reduced costs and increased energy output make offshore wind farms a great renewable source of energy. How can Weatherzone help the offshore wind industry? Weatherzone Business offers a comprehensive suite of services, refined through years of collaboration with the marine, ports and offshore industries, to optimise the safety and efficiency of your operations. Click here to learn more.
16 Oct 2023, 1:47AM UTC
Southerly buster and large swell hitting NSW
A strong southerly change will move up the NSW coast on Monday, whipping up a large southerly swell in its wake. The fierce winds are associated with a low-pressure system sitting in the Tasman Sea which is extending a cold front along the NSW coast. The southerly buster has already hit far eastern VIC and the NSW coast with Gabo Island recording a 107km/h wind gust and a mean wind speed of 70km/h on Monday morning. READ MORE: What is a southerly buster? Ahead of the change, gusty westerly winds are expected to impact parts of the state, with mean wind speeds reaching 20 knots and gusting up to 30 knots at Port Botany and Sydney Airport. The gusty southwesterly is expected to reach Sydney and Port Botany at around 4pm AEDT on Monday afternoon, October 16. The map below shows the gusty southerly change near the Hunter region later Monday afternoon. Image: ECMWF forecast wind gusts at 5pm on Monday, October 16. A large southerly swell will also move up the NSW coastline on Monday afternoon and evening. The map below shows significant wave heights could reach five metres offshore the NSW central coast early on Tuesday morning. Image: Wave Watch III significant wave heigh at 5am Tuesday, October 16. The remainder of the NSW seaboard could see swells reaching 3-4 metres from late Monday into Tuesday, as the hefty swell moves up the coastline. The beaches along the NSW coast that face the south could see some erosion with this swell. The strong southerly winds and large swell will continue to impact the NSW coast until Wednesday morning when the low moves further away from Australia. Weatherzone Business offers a comprehensive suite of services, refined through years of collaboration with the marine, ports, insurance and offshore industries, to optimise the safety and efficiency of your operations. We work with you to understand your intrinsic operational challenges and customise high-precision forecasting, met-ocean, insurance and aviation services to your exact location and operational scope. For more information, please contact us at email@example.com.