CLIMATE - LOOKING INTO EARLY HARVEST 2021.

Updated: Sep 11, 2021

This forecast will be updated twice weekly as we move through Harvest 2021/22.


We know the trends have been supportive of widespread above average rainfall chances, but rather than taking stabs in the dark, I think having data sets explained and communicate that the weather is not fixed in one forecast, that it does change so for you to make the most of my product, and if this is all you care about - COME BACK - TUESDAY AND FRIDAYS!!


HEADLINES


  • Indian Ocean expected to strengthen through to a peak during the coming 6-10 weeks, with the rainfall increasing to above average values over northern and eastern Australia in response to that.

  • The warmer than normal conditions are expected to continue over the coming 6 weeks with some moderation in the heat levels over the NT and QLD with above average rainfall.

  • Harvest could be problematic with widespread rainfall at times across the nation and higher humidity.

Rainfall Data - Euro next 6 weeks

Rainfall looks to increase as we work through the back half of September as we see a trend towards more influence from the Indian Ocean and the tropics waking up, the more moisture over northern Australia is likely feed south and southeast over coming weeks. As the rule has suggested, we would be getting wetter through September nationally and this is likely to peak through October, in line with the peak of the negative IOD phase. So that looks reasonable and on track to verify at this time looking at the data.

CMC Rainfall for the coming 5 weeks

CFS Rainfall for the coming 6 weeks

Rainfall Anomalies Next 6 Weeks

Rainfall chances are looking reasonable for those wanting additional rainfall, especially for inland areas, with only a few pockets of drier areas possible during this time, however we are moving into the convective season, meaning rainfall distribution becomes more uneven and as we saw with last week's event, it can take one system to bring a month's worth of rainfall at one time, these models do not have the skills on those specifics this far out.

Euro Rainfall Anomalies - Next 6 weeks.

CMC Rainfall Anomalies - Next 5 weeks.

GFS Rainfall Anomalies - Next 5 weeks.

A much drier bias which I am not siding with at this time, as much as people want to go dry dry dry to feel like they are protecting themselves from disappointment, reality is, the weather will do what it will do, and the truth in these models lay somewhere in the middle so I am discounting the super dry outlook and the super wet outlook, Euro for the win!

SHORT TERM

Week 1 - Rainfall September 10-17th 2021

More details can be found in the medium term forecast about the impending rainfall opportunities.

Week 2 - Rainfall September 18-25th 2021

More details can be found in the medium term forecast for further details about the rainfall in the medium range in mid month as moisture deepens.

Rainfall Anomalies - September 10-25th 2021

Rainfall anomalies for the coming 2 weeks remain fairly seasonal for most of the nation, however as noted, the moisture from the northwest is starting to build and finally impacting chances for meaningful rainfall over much of the nation from the second half of September. With the engine room for the wet phase to continue strengthening, it is likely that moisture will continue to pool over northern and western Australia and be propelled southeast and east.

Rainfall Anomalies - September 10th - October 25th 2021

% chance of exceeding the median rainfall for the next 6 weeks

This is a preliminary forecast and if you are looking for dry weather for the harvest this year, you may need to factor in some difficult periods of weather into October. Does not mean we wont have dry spells, but when it rains, it will be productive!

Temperature Anomalies - This Week - September 10-17th 2021

Note the see sawing temperatures over the coming weeks, an important ingredient in increasing instability as these airmasses clash. Throw in moisture and you get rainfall and storm outbreaks!

Temperature Anomalies - Next Week - September 18-25th 2021

Note the flip of temperatures for the following week and that pattern does look to continue into the end of month and indeed October, though the heat values will increase (as expected) as we go through the coming 6 weeks.

Temperatures Anomalies - September 10th - October 25th 2021

% chance of exceeding the median temperatures for the next 6 weeks

The temperature roller coaster ride is expected to continue for the time being, though I think the heat will likely win out over the coming 6 weeks through southern Australia, just, but there will be cooler periods under rain events and spells of below average temperatures can be expected. As you move into the middle of October, the temperatures over the north may start to moderate a tad with above average rainfall and that may fuel a very wet 6 weeks leading into November and spark up a storm season through NSW and QLD.

Temperature Anomalies next 5-6 weeks.

The models are starting to relax on the temperatures being well above average over much of the nation, banking on the IOD peaking in the negative phase and a developing positive SAM phase into the back half of this month and into early October. Also seasonally, we see more easterly winds dominate the nation in relation to the southern migration of the high pressure belt over waters south of Australia, again, increasing rainfall chances over QLD and NSW, as well as the tropics. That seems relatively normal in any year but with the elevated SSTs over the Coral Sea and Pacific, heavier moisture loads may be projected into the east and north, and then drawn south and southeast with troughs and fronts, leading to more cloudy spells with rain and hence, a moderation in temperature.

CMC Temperature Anomalies for the coming 30 days.

Euro Temperature Anomalies - Next 30 days from September 25th.

CFS Temperature Anomalies - Next 30 days from September 24th.

GFS Temperature Anomalies - Next 30 days from September 13th.

So I will update this again on Tuesday next week and I am expecting the rainfall chances to jump up so even though it is quiet, NOW is the time to prepare.


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