Latest news with #LaNina-like
Sky News AU
4 days ago
- Climate
- Sky News AU
Australia's incoming deluge: 'Strong odds' of significantly wetter than usual weather in the NT, Queensland as Pacific Ocean gives clues that La Nina could return
There are strong odds of Australia's late winter and spring months being wetter than usual - and significantly so in the NT and Queensland - with Pacific Ocean indicators pointing to a potential La Nina event in 2025. The year so far has been marked by rain and floods in the east and drought in the south, with wet weather now suddenly picking up in the drought-stricken southern growing regions that need it most. Now, this Sky News Weather climate analysis can reveal that many more rain-bearing systems are on the way. Indian Ocean Avid weather watchers will no doubt be aware that there is plenty of talk about a negative phase of the Indian Ocean Dipole (-IOD) developing and aiding rainfall across Australia. The Indian Ocean lies to Australia's west. It is currently in a neutral state with the IOD sitting at -0.04C. This value needs to fall below -0.4C for at least eight consecutive weeks for these developments to be declared a -IOD event. It's still a long way off, but forecast models have been in strong agreement for some time that an event is a significant chance to take place. Its influence could be noticeable from as early as late August if it drops below the threshold in the coming weeks. Pacific Ocean The ocean to our east is the largest in the world – covering more than 30 per cent of the world's surface. Its size and proximity have contributed to its outsized influence on our weather. This mass expanse of water has played a significant role in helping the last five financial years exceed the nation's median rainfall. We had three back-to-back La Ninas, then an El Nino then a 'La Nina-like' pattern that was declared by Sky News Weather and US Government's climate organisation NOAA, but not by the Bureau of Meteorology. Right now, the official value of the Nino3.4 index is –0.14C. However, when comparing the temperatures in the middle of the Pacific Ocean to those through the rest of the world's tropics we can see that we are more clearly on the La Nina side of neutral. The Relative NINO index is therefore more appropriate to use in a changing climate – currently sitting closer to –0.4C. Forecast models have suddenly come into line agreeing that significant cooling of the central Pacific is likely. Between July and September, the median of nine leading models cools the NINO region by between 0.2C and 0.7C with an average of 0.45C. Therefore, there is a significant chance that the September value of the Relative NINO index will be close to -0.8C. This puts us on the border of a weak La Nina event. But like last year, even if it cools a bit further than that, the Bureau will probably say we are experiencing 'La Nina-like conditions' without declaring an event - as official thresholds are unlikely to be met. Rain odds increasing for most According to the average of the nine aforementioned models – including the Bureau's – there is between a 60 per cent and 90 per cent chance of above median rainfall across Australia from August to October. This is a notable increase on the previous forecast for the same period – indicating the growing confidence in the upcoming rainfall pattern. The odds are strongest in the NT and Queensland – meaning that parts of the dry season and 'build-up' months could be significantly wetter than usual – but this is still nothing compared to the wet season. Further south, rainfall should also be very handy in drought affected regions of SA, Victoria and possibly Tasmania and Western Australia – although their rain chances are not quite as high. Many farmers will remember the last time we had strong rain odds at this time of year. Rain gradually picked up through the winter of 2022 before the country saw its second wettest spring on record. Forbes experienced near-record flooding and the Murray had its biggest flood since 1956. Models are not quite as extreme in their forecasts this year as they were in the lead up to that event. However, similar rainfall patterns cannot be ruled out through the coming months as evidenced by this week's uptick in wet weather. Sydney and the NSW coastline could miss out Sydney and the NSW coast have been pretty wet this year. Historically the first half of the year is the wetter time of year in these areas. It's therefore unlikely that the second half of the year will be wetter than the first half. Further to that – a lot of the upcoming rainfall is expected to favour the NSW ranges and areas further west. Therefore, it seems likely that rainfall in Sydney and up and down the NSW coast should be somewhat closer to normal. Locals in those areas may not notice the drenching affecting much of the country. Watch Sky News Weather on the Sky News App or on Foxtel's Channel 601 for the latest forecasts and seasonal outlooks.
Otago Daily Times
08-07-2025
- Climate
- Otago Daily Times
More drenchings forecast
A truck and a car negotiate recent flooding in Portobello Rd, near Bays Junction. PHOTO: STEPHEN JAQUIERY More significant rainfall and flooding events may drench coastal parts of Otago over the next three months, as moisture from the tropics and low pressure systems flow over the country. Earth Sciences New Zealand (formerly Niwa) forecasting principal scientist Chris Brandolino said global climate models were strongly signalling the possibility of enhanced low-level convergence in the western Pacific and areas north of New Zealand. "This could draw tropical and subtropical air masses into our region, increasing the likelihood of wetter-than-normal conditions over the next three months. "There is therefore an elevated risk for heavy rainfall events, including those associated with landfalling atmospheric rivers." It could lead to potentially significant rainfall and flooding events, he said. However, it also meant seasonal air temperatures between July and September were expected to be above average across all regions of New Zealand. "Thus, while cold snaps and frost will occur, they are expected to be less frequent than usual." Around coastal Otago, temperatures were most likely to be above average, rainfall totals were about equally likely to be above normal or near normal, and soil moisture levels and river flows were about equally likely to be near normal or above normal, he said. "Chances for heavy rainfall events are considered elevated during the three-month period, potentially leading to flooding, particularly in areas with saturated soils." On the West Coast, Southern Alps and foothills, inland Otago, and Southland, temperatures were also most likely to be above average, he said. But rainfall totals were about equally likely to be near normal or below normal, soil moisture levels were about equally likely to be near normal or above normal, and river flows were most likely to be near normal. Mr Brandolino said Enso-neutral weather conditions remained present in the tropical Pacific. Last month, atmospheric patterns in the Pacific continued to be intermittently consistent with weak La Nina conditions, but more recently, ocean temperatures had shifted away from previous La Nina-like characteristics.
Otago Daily Times
01-06-2025
- Climate
- Otago Daily Times
A warmer winter is on its way
Electricity bills may deliver less of a hammering this winter if Niwa's outlook for the next few months comes to fruition. It shows temperatures from June to August are "very likely" to be warmer than average this winter, meaning fewer cold snaps and frosts than usual. Niwa National Climate Centre forecasting principal scientist Chris Brandolino said El Nino Southern Oscillation (Enso) conditions in the tropical Pacific remained neutral at present, but there were "residual signals" that indicated weak La Nina conditions were persisting. Occasional La Nina-like atmospheric patterns might still emerge over the next three months, he said. "However, international guidance indicates about a 70% chance for the tropical Pacific to remain in an Enso-neutral state over the next three-month period." He said higher-than-normal atmospheric pressure was expected to the east of the country, leading to northeasterly flow anomalies that might shift to a more northwesterly direction towards the end of the three-month period. That means seasonal air temperatures are expected to be above average across all New Zealand regions for the winter season. "While cold snaps and frosts will occur, they are expected to be less frequent than usual." On the West Coast, Southern Alps and foothills, inland Otago, and Southland, temperatures were very likely to be above average, he said. Rainfall totals, soil moisture levels and river flows are about equally likely to be near normal or above normal. Temperatures were also very likely to be above average along coastal Otago, he said. "Rainfall totals are most likely to be in the near normal range, and soil moisture levels and river flows are about equally likely to be near normal or above normal." Mr Brandolino said for the remainder of the calendar year, Enso-neutral conditions were expected to persist. "The guidance available, however, suggests the possibility for La Nina conditions to return by summer 2025-2026." La Nina can bring more northeasterly winds to New Zealand, leading to drier conditions in the south and southwest of the South Island.
