CLIMATE - HARVEST AND THE WEATHER - UPDATED 6 WEEK OUTLOOK.

We are another week closer to many people hitting crunch time with their crops, a crucial 3-4 weeks of weather on the way for the plants in the ground and then we need to know what conditions are like through harvest.


Well I can give you some guidance on both of those issues this morning.


Lets take a look - notes on all the data below with my forecast charts.

Rainfall Outlook - October 5-November 19 2021

% chance of exceeding the median rainfall for the coming 6 weeks.

No real change from the previous update and as stated in the video, the tropics are becoming more alive with rainfall, the moisture is likely to follow the same cycle of being drawn through the Central and Eastern portions of Australia via upper level winds. The features that needs to lift the moisture into areas of rain and storms, will be the presence of troughs. The more persistent the easterly winds over QLD and NSW, the more likely the rainfall will be above average. But near 100% chance of above average rainfall for parts of the NT and QLD as well as southeast NSW and northeast VIC (note nothing is ever 100%). Drier weather may resume over parts of the southern parts of WA which is seasonal, and near normal odds for the remainder.

Temperature Outlook

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

No change from the previous update with the cold bias continuing over the eastern inland and possibly continuing over the SWLD of WA where persistent ridging and onshore flow could keep temperatures down. It is that time of year that you are set to sweat through NT and QLD as the humidity increases, as mentioned in the last tropical update, this was forecast to be the case and continues so. That humidity will be felt more over southern and eastern areas of Australia through November.

CLIMATE DRIVERS FOR THE COMING PERIOD.

The drivers remain unchanged, with the data sets coming through from the ENSO region in the coming days - an update will follow.


For the SAM - It will remain near neutral for most part, it has dropped below the neutral threshold this week as expected (hence the cold fronts) but I am expecting it to turn positive through mid month and stay there for the remainder of the month, and most climate models signal that shift. Once the SAM goes positive, the easterly winds return.

Indian Ocean - It remains negative and with previous updates, expected to play some part in conjunction with the Coral Sea, dragging more moisture throughout the northern parts of the nation and into the central and eastern states. I update this frequently in the medium term forecast.

ENSO - Conditions are trending La Nina like of late and with the SSTs above normal over the western Coral Sea and the SOI values, some of the parameters showing the trend to the La Nina phase. More details to come this week.


RAINFALL DATA - Refer to the video for further information


Euro Ensemble Rainfall Accumulation - Next 7 Weeks

A wet period continues and likely to be more extensive and heavy than what we have seen in the last week over southern and eastern Australia.

Euro Ensemble Rainfall Anomalies - Next 7 Weeks

Note the wet signal for much of the inland - though watching the dry bias about the east coast of SEQ and NE NSW coastal areas. Not so sure on that just now.

Euro Ensemble Control Rainfall Accumulation - Next 7 Weeks

Note the bias of very heavy rainfall off the south coast of NSW - perhaps picking up on the elevated SSTs sitting off the coastal areas there. Not impossible but that sort of rainfall could occur anywhere through the southeast and eastern inland of Australia in current guide.

Euro Ensemble Control Rainfall Anomalies - Next 7 Weeks

This reflects the convective nature of the rainfall and being able to pick who gets above average or below average rainfall nationally is very tricky, however the more likely of rainfall being above average will be over the NT and through NSW and VIC.

CFS Ensemble Rainfall Accumulation - Next 6 Weeks - Member view

I have outlined this in my video - but to show you some of the members that make up the full data that you see. Relatively good agreement on the wet signal to continue, the member in the lower right is clearly the wettest of this bunch.

CFS Ensemble Rainfall Anomalies - Next 6 Weeks

This is messy to look at but you can see the persistent anomalies across the nation, the tropical zones being in red should be ignored as the models render tropical rainfall poorly. The interesting features of the outlook would be sitting off WA and through SA, Indian Ocean influence perhaps?

GFS Ensemble Rainfall Accumulation - Next 5 Weeks

Still looking very damp in the coming 5 weeks, so the remainder of this month, it will be tough to dry out heading into harvest over the east and south, we could also see flooding risks increase over the east and southeast. The remainder of the nation looking seasonal, the northern tropics, wet and humid.

GFS Ensemble Rainfall Anomalies - Next 5 Weeks

This model has started to move wetter for the east, the southern coastal areas of the nation trending drier which is not unusual, especially for the SWLD. For SA it is more conditional on rainfall moving north and east through to the eastern inland. The NT looks wet over the Top End. Note, the rainfall event this weekend into early next week could see 1-3 inches of rainfall above the norm in parts of Central Australia.

CMC Ensemble Rainfall Accumulation - Next 4 Weeks

Next 4 weeks continues to be wet, in line with the shorter term data set from the same model, it has been bullish in keeping the nation wet and has picked the inland event over the NT and SA this weekend ahead of other models.

CMC Ensemble Rainfall Anomalies - Next 4 Weeks

Wetter as we go through October seems to be the theme. Interested that it has the slight bias to wetter than normal back towards northwest Australia and the Indian Ocean, picking up on the dipole influence.

CANSIPS Ensemble Rainfall Anomalies - October

Wetter as we go and note the moisture seeping south from the tropics through the next few weeks, starting from this weekend, I really want you to pay attention to this shift and then verify it against these updates.

CANSIPS Ensemble Rainfall Anomalies - November

The wet signal cranks further over the north and if this verifies, then November and December will turn even wetter than what we have seen. I will state that flooding becomes a high risk especially over the saturated catchments, but inland areas over the NT and into central and western NSW and southern QLD could quickly become saturated increasing flood risks for summer, especially with a La Nina looming.


TEMPERATURE DATA - Refer to the video for further information


Euro Ensemble Temperature Anomalies - Next 7 Weeks

No real change from the previous update.

CANSIPS Ensemble Temperature Anomalies - Next 6 Weeks

The colder bias has strengthened thanks to the wetter signal off this model, so it is conditional.

GFS Ensemble Temperature Anomalies - Next 5 Weeks

This model has calmed down the warm signal, indicating the overwhelming push to bring up rainfall for much of the nation.

CMC Ensemble Temperature Anomalies - Next 4 Weeks

This model has been showing a cooler bias the whole way through for inland areas, I think it is running a little too warm for the east coast, with my belief the easterly wind regime will be in full force. But will watch trends.


AGRICULTURAL


Soil Temperature Forecast Next Fortnight

The soil temperature is expected to increase gradually through the coming fortnight for areas north of SA and into QLD and perhaps northern NSW. But for the remainder, the temperatures are now moving below average for this time of year, thanks to cloud cover and frequent rainfall expected. This may retard some growth in some areas.

Soil Moisture Content

The wet 18 months over the southeast has seen the catchments unable to dry out sufficiently, most areas in the blue shading sitting at 100% capacity in terms of water holdings, including northeast VIC, the ACT and the southern and central areas of NSW. These areas are in a high chance of flooding throughout the Spring and Summer. With the forecast rainfall in the short and medium term, the flooding is expected to remain a high risk over the coming months. Quite wet through the SWLD of WA and moisture over the NT has remained quite decent since last wet season. Can you pick out the Goyder's Line in SA?

Flood Risk Areas Next 6 Weeks

Flood risks remain elevated in areas as explained above and also a low chance for the outback of NSW through SA and into the NT with persistent inland rainfall with troughing in the region.

Drought Risk Areas Next 6 Weeks

Even with areas of below average rainfall and some areas still in drought, with forecast rainfall across the nation there is no new areas of drought developing.

Another update on this is due out by Friday with more.


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