Ugly sea surface temperatures

Local sea surface temperatures — in the Great Australian Bight and northwest Tasman Sea — are the strongest single influence in my snow depth prediction model. That’s for the season peak snow depth at Spencers Creek, midway between Perisher Valley and Thredbo, NSW, as recorded by Snowy Hydro Limited.


Colder winter sea temperature anomalies (differences from the long term seasonal averages) correlate strongly with more snow. Last year local sea surface temperature anomalies dipped sharply in winter, boosting my predicted snow depth and perhaps the actual depth. Low SSTs may have partially counteracted the strong El Niño conditions which prevailed through winter 2015 (the winter average SOI was -15.5).

Where are local sea surface temperatures headed? Here is the recent record:

Recent sea surface temperatures

Recent sea surface temperatures

That spike to +1.1 °C in October was the highest monthly anomaly on record in our area of interest, and by a fair margin. There is of course a strong, long term warming trend, which doesn’t help:

Local sea surface temperature anomalies

Local sea surface temperature anomalies

But it gets worse. The HadISST dataset I use runs up to two months behind real time. The Australian Bureau of Meteorology plots different, near real-time data (anomalies from a slightly different base period — 1961-1990 rather than 1951-1980). The recent form from that source looks, frankly, terrible:


Time will tell.

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