CLIMATE - A DRY SPELL FOR SOME, BUT HOW LONG DOES IT LAST?

I do enjoy seeing a drier spell in the outlook, especially after how busy the weather pattern has been quite frankly all year at a national level. You get to now sit back and take a look at the data sets with less contamination from widespread rainfall events in the short and medium term.


So, this outlook will offer some very interesting insights into not only the remainder of June, but July as well and what may lay ahead into August and then Spring as well.


Let's get into it and take a look


FORECAST VIDEO - TUESDAY 7TH OF JUNE 2022

RAINFALL

%Chance of exceeding or not exceeding the median rainfall for the period until the 21st of July 2022

The guidance from the models as talked about last week is shifting, we are now moving into the cooler season rainfall distribution and the longer-range modelling becomes a poorer in June and into early July. So it is that time of year we start to see some larger swings from update to update in the data, but you will see more subtle changes to the forecasts on Tuesdays and Fridays over the coming weeks, so stay close to the forecast and cross check these updates with the short- and medium-term forecasts.


NORTHERN WA

The continuation of very high rainfall totals for western and adjacent interior parts of the Pilbara and Gascoyne with local flooding still a risk through this period. A drier bias may develop through the interior at times, but remember, many areas here only see up to 10mm for this period, so it does not take much to get well above the average in this zone. But this is directly linked to the negative IOD which will likely strengthen through this period.

SOUTHERN WA

Not a great deal of change despite the models split on the dry/wetter bias through the SWLD, it is important to look for trends over the course of a few weeks rather than one run at a time. I have moderated the above average rainfall chances for the western coastal areas through this period, most places should scrape together at least seasonal rainfall through this time with the higher probabilities located further to the north into late July.

SOUTH AUSTRALIA AND REMAINING SOUTHERN COASTAL AREAS OF THE NATION.

Leaning towards above average rainfall for many areas, on the back of what we have seen with the cold fronts of late, the rainfall was well above normal in many locations which was opposite to what the modelling was supporting so applying the increased rainfall totals to frontal weather will continue for the time being. Moisture from the Indian Ocean Dipole will remain more active and have higher influence back through WA before it spreads further south and east through July into August as the Winter season peaks. This is where we see widespread rainfall developing over interior parts.

SOUTHERN AGRICULTURAL AREAS

The leaning above average rainfall bias related to the elevated moisture profile running through the nation's south and across the western interior is the right call based on the past 2 weeks of rainfall across southern Australia. But will be watching closely the trends over the coming 72hrs on the myriad of climate data pouring in and I will adjust, if necessary, on Friday. For now, this is a low confidence forecast for the region.

VICTORIA

The wetter than normal weather that we have been experiencing in many areas of the southeast will continue and that drier bias that has been observed in the lee of the Great Dividing Range will also continue in the westerly wind regime. The wet weather is likely to continue despite a quieter period coming up and I do think we see higher rainfall totals developing through the back of June for Victoria and that may increase over the northern areas from July and into August (that is just outside of this period).

SOUTHEAST AUSTRALIA

The leaning bias to above average through a large section of the interior reflects the ability for moisture spreading throughout the interior from west to east, with a drier bias along the east coast to persist. But overall, this may be the quieter and "driest" period through Winter. It is expected that the weather turns wetter throughout July and into August. That is in line with the main influencer, the IOD remaining negative and strengthening further.

EASTERN INLAND

Not a whole lot of change to the forecast from last week, but I am moderating the impact of the moisture spreading through the jet stream as it appears that the moisture out of the Indian Ocean is shifting further south and meeting the westerly wind belt, spreading rainfall through southern and central inland parts of WA and into much of SA and then into the southeast inland, some of that moisture will likely drift into the eastern inland of NSW and southern QLD but the main triggers aligned with the moisture looks to be focussed over the southeast states which is expected at this time of year.

NORTHERN TROPICS

Remaining more humid than normal overall but there will be periods of drier air at times to offset the lingering wet season feel. The higher rainfall chances above the norm are set to be found over the NE Top End and throughout Cape York, but as mentioned, these areas being in dry season, do not need a large amount of rainfall to move above the average in the dry season.

TEMPERATURES

%Chance of exceeding or not exceeding the median temperatures for the period until the 21st of July 2022.

The cooler signal across the nation is set to continue, mainly out through the west and pockets of the interior and along the ranges in the east, which is in response to the higher prevalence of moisture and cloudy skies running throughout the jet stream via the Indian Ocean. Noting that the remainder of the nation may come through the next 6 weeks generally at seasonal values, that is factoring in the colder weather throughout the southeast over the coming week, that means warmer days are also likely to feature at times. So, the talk of the Winter being brutally cold is not factual and based on anything other than the experienced weather right now.


SOUTHERN WA

The cooler bias over the western interior is based on the persistence of cloud and likelihood of further rain. The remainder of the southern coastal areas and along the west, the elevated SSTs are forecast to keep the colder bias at bay for coastal communities and adjacent inland areas. The persistence of wet weather and higher humidity values are forecast to mitigate frost risks.

NORTHERN WA

The cooler bias over the Pilbara and Gascoyne is expected to continue across the course of the next 6 weeks linked to the persistent cloud bands and rain spreading from the coast and inland, these values could be increased further if the frontal weather linked to a negative SAM phase persists in the short- and medium-term forecasts. This will then drag more moisture and cloud across the country. The Indian Ocean Dipole in place keeps northern areas of the nation warmer and more humid than normal.

TROPICS

The warmer than normal bias will spread right throughout the tropics leading to a hot dry season but with the elevated SSTs, the dry season will be interrupted as expected, with higher humidity values in the lower levels making the season uncomfortable. Down to Central Australia, we will be seeing a cooler bias sitting underneath the persistent cloud cover running through the jet stream. That signal will strengthen through August and into Spring. Generally seasonal values for much of QLD south of the sub tropics.

EASTERN AUSTRALIA

The cooler bias is forecast to persist for some parts of the ranges, particularly on and to the west of the divide. Now this cooler bias will come and go throughout the period which is in response to the moisture and cold fronts likely moving through the westerly wind belt. The colder weather we are experiencing right now will moderate and I think we see much warmer weather developing once a large Winter high sits over the Tasman Sea. So, there will be variation in the temperatures over the interior, but brutally cold weather for the whole season we are seeing now, that is not likely under current guidance. But Spring could be much colder than normal if rainfall rates verify.

SOUTHEAST AUSTRALIA

I have just brought back that cooler bias for inland areas of NSW and northeast VIC with the colder air likely behind cold fronts, becoming trapped under high pressure and possibly seeing the increasing frequency of weather events moving out of the west, not allowing the atmosphere to warm up for longer periods. There will be warmer weather on the way, but overall, the cooler bias will continue over parts of NSW. Near seasonal weather is forecast for the southeast and southern Ag areas of the country.

SOUTH AUSTRALIA

Not a huge amount of change to the forecast from last week. Watching that cooler bias running through the interior, the current orientation of the cooler bias will be found along the jet stream running from west to east but that could shift more north to south, if we find that the SAM turns more negative than neutral over the coming 2-3 weeks which the guidance suggests. That could mean more volatile weather on the way.

Key Points

More information on these points can be found in the video.

Additional Points

Refer to video for more information on these points but I will be posting more about these points in the weeks ahead so stay tuned. It is not just talking about weather we can see on the charts in the short term, it is planning for a range of possibilities moving into Spring and the impacts on your bottom line! Plan for the worst and hope for the best!

More to come on further climate information throughout the week including a look at the Climate Drivers tomorrow, and where they are and where they are going, and I will have another look at the August Outlook perhaps later this week or into the weekend. Plus, further issues moving into Harvest 2022 very soon and a look at Summer 2022/23.

201 views0 comments