A cold front pushing through southeast SA, VIC, TAS and southern NSW is generating showers, gusty winds and Alpine snow. A broad area of high pressure is keeping elsewhere mostly dry and settled.
Weather in Business
Today, 5:55AM UTC
Wow! 30-degree temperature difference in NSW
It's not often that any Australian state or territory has two locations with temperatures that are separated by 30°C or more at any given point in time. But that has been the situation in New South Wales for several hours on Friday afternoon, with weather stations in the state's northeast and southeast separated by 30 degrees or more. For example, at 1 pm: Casino, in the Northern Rivers, was sitting on 28.5°C Thredbo Top Station, down in the Snowy Mountains, was –3.0°C That's a gap of 31.5°C. Which is a lot! If you're interested (and you're a Weatherzone reader so we know you are), the average August top temps in Casino and Thredbo respectively are 22.7°C and 0.5°C. So that's a 22.2°C gap, on average. Meanwhile at 3 pm, when we took the screen grab of live temperatures in the image below, Thredbo Top tation was hovering on –2.1°C, while Casino was on 28.0°C, a gap of 30.1°C. That gap of 30 degrees or more has persisted for at least three hours. Why such a difference in temps in just one medium-sized Australian state? A cold front passed through southern parts of NSW overnight, bringing snow to the mountains, showers and a few storms here and there, while also dropping maximum temps several degrees on Friday compared to Thursday. For example, Canberra (OK, technically in the ACT but encircled on all sides by southern NSW) had a maximum of 15.9°C yesterday but has not yet nudged 13°C today, and probably won't. That cool air has not yet quite penetrated to the far north-east corner of the state, but it's not too far off, and will arrive later today or overnight, with weekend top temps at most spots in the northeast (below the tablelands) expected to reach the low twenties on Saturday and only the high teens on Sunday. So for now, NSW has a pretty interesting statewide weather situation happening. Is there anything like this happening in any other state or territory? If you pan out and look at temperatures across Australia, you can see a gap of about 21 degrees between the warmest (up north) and coolest (down south) parts of Western Australia. Victoria has a gap approaching 20 degrees between its ski resort weather stations at places like Mt Hotham, and the weather station up in the state's northwest in Mildura. No other state has a differential of more than about 12 to 15 degrees between the warmest and coolest spots concurrently. Whatever you're up to this weekend and whether you like it hot or cold, we hope the weather is kind to you.
Today, 2:43AM UTC
Disappearing Tarn returns as heavy rain transforms Tasmania
The mysterious Disappearing Tarn has returned to kunanyi / Mount Wellington this week after a quintessential late-autumn state-wide soaking caused flooding in Tasmania. August is Tasmania’s second wettest month with a state-wide monthly average of 148.2 mm. This sits just behind July (154.4 mm) and a smidgen ahead of May (135.7 mm) and September (134.9 mm). So, it wasn’t surprising to see a processions of low pressure systems and cold fronts delivering frequent and heavy rain across the state during the past week. However, it was unusual for so much rain to fall in the state’s east, courtesy of a deep low pressure system in the western Tasman Sea. The map below shows that most of Tasmania received around 50 to 100 mm of rain in the last seven days, with a few places exceeding 150 mm. This included 177.2 mm in one week at kunanyi / Mount Wellington, which is more rain than the mountain received during all of June and July combined. Image: Observed rainfall during the week ending on August 18, 2022. Source: Bureau of Meteorology With this much rain in a short space of time, it also wasn’t surprising to see an elusive iridescent turquoise lake suddenly appearing on the rocky slopes of kunanyi / Mount Wellington. The Disappearing Tarn “Like tripping into paradise” is how The Guardian’s Natasha Cica described Tasmania’s Disappearing Tarn when she first laid eyes on it in November last year. The Disappearing Tarn is a small lake that sometimes appears on the side of kunanyi / Mount Wellington after heavy rain. The Tarn’s water is strikingly clear and bitterly cold, and it usually only stays around for a few days before disappearing again. While there is no guarantee that the Tarn will appear after any single rain event, this week’s wet weather was enough to bring the lake to life. Image: The Disappearing Tarn appeared on kunanyi / Mount Wellington this week, following several days of heavy rain. Source: @0dansmith / Instagram Images: The Tarn also filled up during a wet week last winter, seen here on June 14, 2021. Source: @jac_hittheroad / Instagram (top) and @allie_leech / Instagram (bottom). Flooding Continues This past week’s rain has also caused flooding in parts of Tasmania, including the Macquarie, North Esk, South Esk and Meander Rivers. Flood warnings were still in place for these four rivers on Friday, with strong and dangerous flows expected to persist over the coming days. Images: Flooding in Cataract Gorge at Launceston on Thursday, August 18. Source: @tamaratimtamwebb / Instagram Looking ahead, more rain is likely to fall over the coming week as two cold fronts cross the state on Friday night and on Monday. Image: Forecast accumulated rain during the next week (seven days ending at 10pm AEST on Thursday, August 25). Check the latest flood warnings for the most up-to-date information on river heights and future flood risk.
18 Aug 2022, 7:28AM UTC
'Absolutely putrid' conditions ahead of fresh snowfalls
We warned you in our story yesterday that there might be a little rain today ahead of the next snowfalls in the Aussie High Country, and it seems like there's more than just a "a little" rain in some parts of the mountains. "Absolutely putrid at Mt Buller now. Hosing rain, windy, shrouded in fog. Do not like." These words, which no snow-lover wants to hear, were posted by a sodden skier on the forum at leading snow industry website ski.com.au at 2:45 pm on Thursday. This photo from Mt Buller backs up his observation, showing a pretty miserable scene with puddles of slush and water among the snow. Image: Not the greatest arvo of weather up at Mt Buller. Source: Supplied. Rain is also falling at other Victorian ski resorts and appears likely to move through the NSW ski areas this evening. But don't despair – snow is on the way! The question is: when will it arrive? With luck, the rain will turn to snow later tonight, and there’s an interesting way you can tell that colder air is coming. In May this year, just ahead of the ski season, we wrote a story about Mt William, a weather station situated at 1150m above sea level in The Grampians in western Victoria. If snowy weather is heading towards the mountains, the airmass will almost always pass through Mt William, which lies about 500 km west of the mountains. Mt William dropped almost two degrees, from 6.5°C to 4.7°C, between 2 pm and 4 pm. That's a time of day when temps would normally be rising, so it's a good indication that a colder airmass is indeed on its way. Let's move on to this week's wrap of snow conditions in NSW, Vic and Tas. Should I go to the snow this weekend? Go. As we said last week, dress for snowy weather, but go. It should be a really great weekend down there with light to moderate snowfalls on Saturday, clearing at most resorts on Sunday before more snow comes early in the new week. Mt Hotham, Falls Creek and Mt Buller all have most of their lifts open despite Thursday's rain, so check the highlighted links for more info. Australia's lowest mainland resort, Mt Baw Baw, is still suffering from a thin snow cover, but still has four of its seven lifts open, with things set to improve in coming days. More info here. NSW Image: Thredbo has been looking pretty decent lately. Image: Thredbo Resort Facebook. Thredbo, Perisher, and Charlotte Pass all have all or most lifts spinning despite the rain, so check the highlighted links for updates. Tasmania Still not such great news at Mt Mawson and Ben Lomond, where the patchy snow cover remains suitable only for snow play, however a stack of snow looks likely to come in the next few days, and to very low levels by Monday. The tiny Tassie skifields should get a reboot out of the impending system, which they deserve as their winter has not been so great thus far, with all lifts closed for much of the season. As ever, please check the Weatherzone snow page for the latest cams, forecasts and other info.
Weather in Business
11 Jul 2022, 3:11AM UTC
Record month for wind power in Australia's National Electricity Market
New data shows June was one of the best ever months for renewable energy in Australia’s National Electricity Market and a record-breaking month for wind power. June 2022 was a relatively dry and cool month for much of eastern and southeastern Australia, with frequent periods of strong winds and clear skies. NSW registered its driest June since 1986, while Sydney and Brisbane had their sunniest June since 2004. This abundance of sunshine and wind created an ideal month for renewable energy generation in the National Electricity Market (NEM). The combined generation of solar (rooftop and utility), wind and hydropower across the NEM in June 2022 was 5,969 Gigawatt hours (GWh). This is the third highest monthly volume of renewable energy generation in the NEM in records dating back to 1998. Wind power Wind power had a record-breaking month in the NEM, with 2,527 GWh of generation in June 2022 beating the previous monthly record of 2472 GWh from July 2021. Victoria also set a new record for wind power in June this year, with 1,073 GWh easily surpassing the state’s previous record of 922 GWh from July 2021. Solar Power Solar power also had a strong month, with rooftop generation in June outperforming May 2022, despite May usually being the sunnier month. This was the first year on record where June rooftop solar generated more power than May. Utility solar also continued to see strong growth, producing 589 GWh in the NEM during June 2022, which was a big step up from 445 GWh in June 2021. Hydropower While June was a very dry month for large areas of eastern and southeastern Australia, an abundance of rain earlier in the year ensured that there was plenty of water available for hydropower. The NEM received 1,885 GWh of electricity from hydropower in June 2022, which was the 8th highest monthly value in 283 months of records dating back to 1998. The combination of favourable weather and continued growth in the sector caused June 2022 to be an exceptional, and in some cases record-breaking month for renewable energy in the NEM.
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.