SA - CLIMATE OUTLOOK FOR SEPTEMBER

Lets take a look at the weather heading through September 2021


The weather configuration of the past 2 months has been giving the better rainfall chances for southern and eastern parts of the nation, with coastal areas being the areas that have seen the most frequent rainfall. This will begin to change during the coming 2-4 weeks with the heavier impacts of the seasonal shift beginning in the second half of September. The warmer the temperatures get over the northwest and west, the more moisture in the air, and the larger the rainfall events will begin to move through.


We have already seen in the medium term, some modelling suggesting larger scale inland rainfall events, we will wait and see how that verifies for the end of the month.


Into September, the weather is expected to get wetter as we go, that is in line with the climate drivers and guidance.


Rainfall Outlook for September 2021

% chance of exceeding the median rainfall for the month of September 2021.

The inland areas of the state have the highest chance of seeing elevated rainfall totals against the average, but remember, the outback sees little rainfall, so these values are less impressive. BUT, the chances of exceeding rainfall is a good chance for central parts of the state and decent chance of seeing at lease seasonal rainfall for coastal areas after a few productive months. The wet weather driven by the Indian Ocean Dipole which is expected to strengthen further for the coming 2 months, peaking in the late October or early November. This month will get wetter as we go.

Temperature Outlook for September 2021

% chance of exceeding the median temperatures for the month of September 2021.

Temperatures are expected to be cooler than normal for inland areas due to the increased cloud cover and rainfall chances for the state. This does not mean it won't be warm to possibly hot at times, it just means that there will be longer periods of cooler than average weather underneath rainy spells especially for the second half of the month, but this guidance will continue to refine as we go through the coming 2 weeks, so I will review this again at the end of this month. Some models have a very cool month while others have been milder in their approach which I have covered off in the Climate Updates.

The main climate driver is the Indian Ocean Dipole being in a negative phase bringing that extra moisture and higher chances of rainfall throughout the nation as we track through September, the driver expected to peak during October or early November. In the Pacific we have to keep an eye on the chances of that La Nina developing with another update coming on that early in the new week. Some global agencies have increased the chances to 70% in the spring and summer which would obviously impact the summer and autumnal rainfall as well as head into 2022, so it could be a soggy and humid warm spell.

I will have another look at the chances of La Nina developing on Tuesday and pay attention to the daily forecasts, morning and night for those hanging out for rainfall. Ensure you have the blog page saved on your devices as it refreshes automatically.





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