19 Oct – VIC’s hot corner


SST Anomaly for Australia – RAMSSA

SST anomalies are much more neutral around the country this week, with the negative anomalies in the south and west weakening. One exception is a strong cool anomaly off southern Indonesia due to upwelling.

The stand out feature in Australian waters is a very warm anomaly on eastern VIC coast. SSTs are 2.5 to 3 deg C above normal, even higher than last week.

SST anomaly for VIC and TAS – RAMMSA

There is a strong temperature gradient in a short distance – the inshore waters are much cooler.  SSTs inshore have dropped due to upwelling from several days of northeasterly winds this past week. This was forecasted correctly by last week’s model runs. Batemans Bay is now a chilly 15.8 deg C. Unfortunately the temperature sensor at Eden seems to be broken, but you could expect it to be similar or even colder than Batemans Bay. Port Kembla has also experienced a drop in temperatures due to local upwelling.

SSTs on the slide in southern NSW – MHL

Meanwhile out to sea it is a balmy 20 deg C. As we can see in the SSTAARS climatology below, in October the surface water is usually 17 deg C.

SST climatology for October and the snapshot SST for 15th Oct 2018 – SSTAARS, OceanCurrent

The northeasterly winds along the NSW coast should ease back today and over the weekend, and OceanMAPS suggests that this will allow the warmer water to move back in towards the coast.

The extra warmth is due to a big southward push of EAC water, along with a westward movement of nearby warm eddy. This eddy looked weaker, perhaps dying, a month ago when it was centred at 152.3 E, but now seems to have reformed and strengthened at 150.5 E!

Taking a cross-section west to east – on the same transect and using the same colour scale one month apart – the differences are stark.

Temperature cross section at 38.8 S for 19th September – OceanMAPS
Cross-section of water temperature at 38.8 S for 18th October – OceanMAPS

Firstly, there is a lot more heat. Secondly, the centre of the heat content has shifted westward. This is also confirmed by SLA/geostrophic analysis on the OceanCurrent website .

Snapshot SST images for 19th September and 18th October, red star showing centre of warm eddy – OceanMAPS

The western edge of the warm anomaly is being guided by the bathymetry. The below image shows an overlay of the latest temperature with the OceanMAPS bathymetry.

Surface temperature (shading) and model bathymetry (contours) – OceanMAPS


The following communication has been released to all external users.

The Bureau is making good progress towards solving recent intermittent issues with the ACCESS Global model.

  • ACCESS-G and Auswave-G model output quality in southern polar latitudes could still be impacted.
  • Model output over the  Australian area is not showing any significant reduction in quality.
  • We are working on resolving the issue and are expecting to return to normal operations by mid next week.
  • The Bureau’s official public forecasts and warnings are not affected.

Here at the National Operations Centre we have conducted some verification studies into the performance of OceanMAPS since the ACCESS-G issues arose. There is no obvious reduction in forecast skill. 

  • The data assimilation statistics (innovation and increment) show no significant impact.
  • The ensemble mean forecast error for 2-day forecasts of SST and SLA are unchanged.

Internal users are encouraged to check out the OceanMAPS verification statistics for the Australian region at various lead times:



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