Latest news with #NegativeIndianOceanDipole
7NEWS
5 days ago
- Climate
- 7NEWS
Rain intensifies in both Queensland, NSW and the west as we head into the weekend
There are two major weather systems brewing - one on either side of the country. Let's start with the eastern one, which will be another significant rain system for Queensland, particularly in the southeast near the coast. If you are in between Brisbane and Mackay, please keep up to date with the latest forecasts and warnings, as a low develops off the coast, fed by tropical moisture, resulting in heavy rain. The rain should start to spread across much of Queensland and northern NSW during the day on Friday. A nice drop from this one, rather than widespread intense rain. The activity intensifies on Saturday along the coast with modelling suggesting widespread falls of 25mm to 100mm. Locally up to 300mm in the most affected area near the low, which is currently between Maryborough and Yeppoon. This one is relatively fast though, with the weather rapidly easing again on Sunday. High pressure brings a dry weekend to the southeast, but in the west of the country we have the next big system move through. Again this will have a good feed of moisture from the tropics - the Indian Ocean - ensuring that the rainband that moves through with the gusty cold front is moisture-laden and brings 25mm to 50mm to the southwest corner, before slowly decreasing as you head inland. This is a strong cold front, and will be accompanied by the usual wind threats. Most of this is felt later Saturday into Sunday. These are ongoing examples of weather systems meeting up with tropical moisture to bring heavier than usual rain for those in the path of the low, trough or front. The global patterns in both the Indian and Pacific Oceans tell us when this injection of moisture is more likely - when we are in a Negative Indian Ocean Dipole (IOD) or a La Nina. Put simply, a Negative IOD is the Indian Ocean equivalent of La Nina, just without the fancy name. They both act to push extra moisture towards Australia. We crossed the threshold into a Negative IOD about a week and a half ago, and remain there this week. Most forecasts have us remaining below that threshold for the next month or two. If we remain there for about eight weeks in total it will officially be a Negative IOD. The Pacific Ocean has weak signs of heading towards that negative threshold too - ie a La Nina. It is one to watch to see if we have both oceans enhancing our moisture over the next few months. It won't ensure rain for all though - only those in the path of the lows.
7NEWS
30-07-2025
- Climate
- 7NEWS
Jane's weather: Rain system with Sydney and much of the NSW on its radar
Earlier this month we moved into a weather pattern where a new, big rain system affects some part of the country every few days. Tropical moisture is fed into low pressure and turned into widespread rain - for those in the path of the low pressure. The most recent system was huge, affecting every Australian state and territory, because the low crossed the Great Australian Bight near the coast and had a cold front stretching up into northern Australia, ensuring rain fell across a huge swathe of land. As always, there are some spots that miss out and the path of this one meant that it was from Melbourne through to Sydney, if you were taking the coastal route. Conversely, the Hume Freeway did extremely well, with falls over 50mm for much of the journey. The next weather system delivered in the west early in the week, then took a path over South Australia and New South Wales. This part was a nice follow up, but nothing significant. While the low pressure part disappears off the east coast, it does leave behind a pool of cold air in the upper atmosphere. This is the energy needed for the next low to form, and the weather pattern has decided that just off the northern NSW coast is the right spot for that low. Coastal lows can pack a punch, as we saw recently with the headlines that screamed Rain Bomb. That particular low developed quickly and deeply enough to undergo what is known as 'bombogenesis', while this upcoming one isn't likely to be quite as severe. We'll still see a lot of rain, with falls over 100mm highly likely along parts of the NSW coast and adjacent inland to the ranges. The winds strengthen too, especially on the weekend when the low is at its deepest, but may fall just short of widespread damaging gusts. Conditions ease early next week after the next big weather system crosses the west on the weekend. While this is occurring the southeast (away from the NSW coast) takes a break under high pressure. That high is likely to 'get in the way' of the next big system approaching from the west, blocking most of that rain early next week. Then a new feed of moisture from the Indian Ocean could develop mid next week. Another juicy, northwest cloudband. One to watch to see what path it takes and which areas see the next significant rain. Why are we seeing all these feeds of tropical moisture? Earlier this week the Indian Ocean crossed the threshold into a Negative Indian Ocean Dipole. A significant milestone for Australia's weather, and a sign that more rain systems are on the horizon.
7NEWS
11-06-2025
- Climate
- 7NEWS
Jane's Weather: Drought stricken farmers finally receive rain over the long weekend
A quarter of Victoria recorded more than 50mm of rain over the long weekend and the majority of southeastern Australia saw more than 25mm. Many places picked up more rain over the three day weekend than they did in the first two months of the year. A few spots located well inland did only receive 5mm to 10mm, but the vast majority saw good rainfalls, incredibly useful after such a long period of well below average rain, transforming paddocks and dams. The big question is - is there any more rain to come? A big, juicy, follow up rain system would be very welcome, but we don't have one of those lining up for the southeast in the foreseeable future. Most areas are likely to see less than 10mm over the next week. The next low is crossing the Bight on Wednesday, heading towards the southeast. This one is going to take a very different path to the last one (that slowly trekked across Bass Strait then out to the Tasman Sea - a perfect path for big rainfalls in the southeast). This one is going to deliver 5mm to 10 mm for parts of South Australia (over the Eyre Peninsula, West Coast and Northwest Pastoral), then rapidly dissipate, bringing hardly anything to the rest of the southeast. It then re-forms over the Tasman Sea late in the week, brushing the NSW coast. There is another system lining up to cross the southwest on Friday and South Australia on Saturday. Then this one also dissipates, with just a little rain for the rest of the southeast on Sunday. That does pave the way for another weather system to come up from the south (skipping southwestern Australia), barrelling through the southeast on Monday into Tuesday next week. At this stage it just looks like a regular cold front, with the best falls (10mm to 20mm, locally more) near the coast and in western Tasmania, drying up as it heads north and east. The outlook for the next few months has the moisture part of the rain equation working well: A neutral Pacific Ocean, with plenty of warmer than average water off eastern Australia (to bring us a local source of moisture rather than the global effects of an El Nino or La Nina); and a developing Negative Indian Ocean Dipole (to give us a big push of moisture from the Indian Ocean). But that's the moisture part of the equation - not the instability part. You need low pressure to turn that moisture into rain and if the lows can't track where they are needed, there won't be much rain.
