Unexpected Record Hot November Across Australia

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Australia discussion: The Australian Bureau of Meteorology indicated November 2020 was the hottest on record. Additionally, the Bureau indicated spring 2020 was the warmest on record for minimum and mean temperature. Rainfall was well below normal in many parts of Australia but not as dry as last year. The November 2020 national average temperature was +2.9C according to the Bureau breaking the record of +2.4C in November 2014.

The climate pattern is very unexpected given presence of La Nina. Normally, La Nina brings wet weather to northern and eastern Australia in November suppressing heat risk. However, November 2020 was another example of local climate being altered by regional SSTA patterns which prove more influential than ENSO. In November 2020 a large mass of very warm water east of Australia (Fig. 1) was well-correlated to the strong upper ridge stretching from New Zealand to Eastern Australia (Fig. 2). Beneath the ridge the anomalous heat was generated.

The springtime rainfall pattern across Australia was feast-or-famine producing unexpected dryness across eastern continent while South-central and Northwest Australia were soaking wet (Fig. 3).

In the 15-day forecast the GFS indicates two areas of heavy rain related to tropical events (Fig. 4). A tropical system may form off the northwest coast and bring heavy rain to that region centered on the 6-10 day period. Meanwhile, a tropical fetch could bring heavy rain in the 11-15 day period to Queensland. Otherwise the GFS is mostly dry.

Fig. 1: Regional SSTA patterns governed the Australia climate in November 2020.

Fig. 2: The prevailing upper air across Australia in November 2020 produced an unexpected hot and dry ridge in the Southeast.

Fig. 3: The springtime 2020 percent of normal precipitation across Australia.

Fig. 4: The GFS indicates two wet weather zones the next 15 days otherwise dryness prevails.