It feels like that all I have been talking about for the past year is rain rain rain, too much over here, not enough over here. Well, it looks like the pattern flipping is starting to shift the wet signal around, thanks to more of a westerly dominance, which is what would expect to see developing in June.
The talk of La Niña having massive impacts through Winter are not quite true. With the waning element in the ENSO ongoing, there is the chance of higher moisture being drawn into the nation from the easterly winds, however, the pattern is now turning into cool season, so the dominance of easterly winds bringing in that moisture should naturally begin to ease and I suspect it will.
The area of interest that many in the media will pick up on as a gimmick is the Indian Ocean Dipole which quite frankly has more of an impact for larger parts of the nation than the ENSO region. Now with that said, we have already been seeing the impacts of the IOD in recent weeks, with widespread rain and flooding over the normally dry northwest of WA.
When this area is running that wet, it is a clue to what is coming for the remainder of the nation down the line of this region, so southern and southeast areas of the country need to pay attention to forecasts in the short and medium term here. I cannot be more clear on this.
Over the far southwest and perhaps pockets of the south, you may escape the worst of the rainfall, but overall, the seasonal average should be met at least regret. Even northern tropics areas are likely to see above average rainfall through Winter, but probably starting in the July through August as everything is at it’s most northern aspect before the warmer season drifts south from August and September.
Let’s take a look at the 6 weeks ahead.
RAINFALL %Chance of exceeding or not exceeding the median rainfall for the next 6 weeks taking us through to the 14th of July
We are looking more winter like in terms of rainfall distribution over the coming period with the westerly wind belt starts to influence weather conditions over the southern parts of the nation. The bulk of the wet bias is looking to be further towards SA, VIC, NSW/ACT and TAS for now, with more infrequent rainfall for the SWLD of WA. This is in line with where the climate drivers are currently placed. The lingering La Nina in the ENSO supports more of a neutral SAM through this time of year, but we are starting to see more negative phases in the outlook which will whip up more cold fronts. But the big impact in terms of rainfall comes from the Indian Ocean, which is running warmer than normal, leading to that above average rainfall over the northwest of the country which then seeds cloud bands over the southeast and central parts of the country, with more rainfall chances spreading nationwide. But this has a habit of bypassing the SWLD of WA. So rainfall in this zone may be somewhat seasonal, but there could be a few that move below average through the Goldfields and Central Wheatbelt. Over the east coast, drier with more westerly winds, but all it takes is one cut off feature to bring about a large scale rainfall event leading to above average rainfall, so for now I am keeping the forecast at seasonal expectations. Above average rainfall over the north of the country is in response to the above average humidity values that are likely to be present at times.
Very much above average rainfall is likely for the Central Inland, through to the Pilbara and Gascoyne and back towards the Kimberly. The rainfall gradient is very tight and the further south you go into the Central West and Lower West, seasonal rainfall chances are expected. However as mentioned, there is a chance that some areas that split the difference between the moisture running through the jet stream and the cold fronts impacting the SWLD, may see below average rainfall, but the signals are not very strong.
Near certainty for above average rainfall to continue through to the middle of July with some heavy falls leading to flooding possible and renewed flooding is also a chance throughout the period. The northern tropics are forecast to be more humid than normal with a chance of dry season rainfall developing. I will mention that in this region, you do not need a lot of rainfall to bring about above average rainfall however, the rainfall numbers over parts of WA are quite excessive, observed and what is to be forecast.
Moving over to QLD, widespread rainfall should nose into QLD but weaken by the time it reaches the west of the state. So, while we are seeing a lot of green, this is typically the drier time of year for the inland so that is to be expected. The east coast looking mainly seasonal, a few pockets may see drier than normal weather but overall, typically seasonal weather expected east of the ranges. The tropics look to be soupy with higher rainfall chances thanks to the elevated SSTs throughout the region.
%Chance of exceeding or not exceeding the median temperatures for the next 6 weeks taking us through to the 14th of July
Not a great deal of change to the temperature guide, with the colder weather expected over large areas of the southeast and south during the next 2 weeks and persistent cloud cover coming through the jet stream over inland Australia, this may lead to areas be well below average for a long duration. The southwest and northern areas could tend seasonal to above seasonal temperatures with higher humidity over the north of the country leading to that region adopting a higher chance of above average temperatures. Mostly seasonal elsewhere but the next 2 weeks does look colder for many Ag Areas in the south and southeast.
Leaning below average for many through SWLD of WA. But where the rainfall is expected to be above the average with thick cloud cover, this is where the below average temperatures will continue with that running towards the SA border and the NT border.
Above average temperatures and humidity values are expected throughout the period for the NT and Kimberly with this a product of the Indian Ocean Dipole developing. The cooler signals are further south throughout the remainder of WA where thick cloud, above average rainfall and humidity will lead to below average temperatures for many.
Above average temperatures are forecast to continue for many areas over the tropics but the further south you go, the more seasonal temperatures are likely to be. There is a lot of blue further south, but that is leaning below average and not necessarily for very much colder than normal weather for the period, but with cloud cover coming through from time to time, this could support some cooler days throughout the period. Nothing brutally hot and dry is expected during this period.
More information is in the video relating to these points
Additional Key Points.
More on this throughout the weeks ahead and should be in the back of your mind where you are looking towards the longer term.
I will try and have a seasonal outlook at some stage this week or into the weekend, depending on the coverage of wild weather moving into the latter part of the week. These will be state based forecasts rather than the broader overview. So more on that in the days ahead.