Time to check the SSTs across the nation and to see the impacts for each state and the climate drivers the ENSO and Indian Ocean, to see how they are performing. We can see the influence of the Indian Ocean Dipole presently, is the phase strengthening as forecast?
INDIAN OCEAN - IOD TENDING MORE NEGATIVE
The classic thermal gradient continues to develop throughout the basin in line with the negative IOD which will start to strengthen further as forecast through the remainder of August and into Spring. The waters may look marginally warmer than normal, but the base for a negative IOD phase is present and warming of the waters is being forecast by ALL international agencies, with the more reliable models suggesting a robust IOD that will get to near 2016 values. Will impacts be the same as 2016? Quite likely but not one event is ever the same but looking at the analogues, I would be watching this very closely from WA, through SA and into QLD, NSW/ACT, VIC. It is the first time since record keeping began that back-to-back negative IOD events have been declared. I forecast that back in January.
PACIFIC OCEAN - ENSO - STUBBORN COOL SIGNAL CONTINUES - WEAK LA NINA/COOL NEUTRAL.
Whatever the international agency you read, they will be calling the ENSO region differently from one another. The SSTs reflect the trend towards the La Nina continuing into Spring and Summer, with strengthening possible through the Summer 2022/23. This will be an area to watch over the course of this month and I will have an update on the ENSO coming up next week.
EASTERN INDIAN OCEAN
This is most certainly the engine room for a lot of woe I suspect for many of our agricultural areas in the east, with the basin warming steadily to levels not seen at this time of year since 2016. The BoM declared the IOD active....IT HAS BEEN ACTIVE FOR A WHILE NOW - and no jurisdiction pushes a button and then it starts to have influence, it has been there for a while and if you follow this page, the warming is not a surprise. So, the continued warming is ongoing throughout the basin, and this is leading to significant moisture plumes being transported via the upper-level winds in the jet stream and then propelled into the interior and southeastern interior. Many areas are looking at being influenced via this region of warmer waters. You don't need the basin to be 6C above normal for it to have impact. Some international agencies have the basin at about 0.5C to 1C warmer than what is being shown here.
NORTHERN TROPICAL WATERS
Waters through to the north of the NT and QLD are forecast to remain elevated but they have been pushed further north in recent weeks, but the Gulf has started to warm again and there are some warmer waters emerging closer to the NT through the Arafura Sea. The cooler waters ringing the northern tropical coast is normal in offshore winds in the dry season and these will reverse rapidly to above average throughout the Spring and Summer.
Elevated SSTS continue throughout the Coral Sea are in response to the ongoing and lingering influence of the La Nina/ cooler neutral phase, that will keep the waters nice and toasty throughout the Winter and into Spring, the impacts to be felt mainly up over the northern tropics through Winter with the higher moisture values and shower activity in onshore winds. The broader impacts over these elevated temperatures will be felt through inland parts of QLD and into NSW from the Spring as the nation warms. The influence also increasing as the winds shift into the easterly wind regime. In the short term, we will see moisture drawn throughout the eastern and southeastern inland of the country via easterly winds but bigger impacts int he short term out east of the nation with very much above average rainfall through the island nations and into NZ.
PACIFIC AND TASMAN SEA
The waters offshore the South Coast of NSW have started to ease inshore but in the Southern Tasman Sea, further offshore we have seen the warmer waters expand, which is quite remarkable given the strong frontal weather and low pressure sitting over that region, that usually provides upwelling of the cooler waters from lower down in the sea surface. At this time, it is bucking the trend and this area of warmer waters would support further deep low formation if a system was to sit over the region. Seasonal values generally elsewhere, though in normal years, we see the waters along the east coast cooler, thanks to the persistent westerly winds. Normal impacts are forecast for now from this region.
BASS STRAIT AND SOUTHERN OCEAN
Not much change in the last 2 weeks. The waters around Victoria generally seasonal and cooler through areas nearby the Tasmanian northern coastal areas. The waters in eastern Bass Strait into the Tasman remains above normal which has supported some deep low-pressure formation this Winter. These waters are likely to modify marginally in the coming fortnight.
GREAT AUSTRALIAN BIGHT
The inshore waters remain cooler than normal thanks to the normal westerly and southwesterly winds. These waters have been largely unchanged in recent weeks. The cooler than normal waters not uncommon for this time of year. Warmer than normal waters are trying to stir offshore but overall, the Bight is seasonal, good to see that it is not colder than normal, which would offset the impact of the IOD which can sometimes happen.
SOUTHERN OCEAN AND SOUTHERN INDIAN OCEAN
The warmer waters around the state's south have been evident in the showery coverage leading to above average rainfall in recent weeks. The waters continue to warm up, not uniformly, however there is sufficient warmer waters around the south and west of the state to lift rainfall rates along cold fronts and with the onshore push, which has been evident and is evident today. Temperatures should be colder than normal with the frontal weather but once we lose the frontal weather into Spring, the days should turn sharply warmer than normal.
I will have more information on this in about 2 weeks to cross check where the SSTs are moving and how they are changing as they will be playing a huge role in the rainfall spread across the nation into the important growing and harvest period.