An active low pressure trough passed through our regions on May 20, accompanied by widespread thunderstorm activity particularly in Victoria and the Riverina and across to the Tablelands.
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Rainfalls were around 15mm at most places.
The low pressure then passed into the Tasman Sea and deepened into a classical east coast low, where it has remained fairly stationary.
With a strong high pressure centered south of the bight, this constitutes a blocking pattern.
The cold, southerly airsteam has penetrated far north into Queensland with record low maximum temperatures for May at Townsville, 16.6; Maryborough, 13.8 and Hervey Bay, 13.5.
Cairns' maximum of 20.3 made it the coldest May day there since 20.0 in 1935, while Charleville's 13.2 last Saturday, May 23 was the coldest May day since 12.2 on May 23, 1959.
Brisbane had a maximum temperature of only 15.1 degrees last Saturday, making this the coldest for May since 1922. Other colder May days at Brisbane were in 1899 and 1904. Such very low maximum temperatures for May in Queensland are not expected to lead to warmer than normal days for at least a week in our regions.
Coonabarabran is facing its coldest May since 1968, and this autumn there could be the coldest since 1956. Melboune is facing its coldest May since 1970.
The first five months of this year in Melbourne have all been wetter than average, and the last and only other time was back in 1896.
There is no need to say that the winter of 1896 was extremely cold over most of the nation - it certainly was; Adelaide recorded its coldest two months on record in July and August 1896.
Coonabarabran's lowest ever temperature was minus 11.4 on July 2, 1896.
The spring of 1896 did warm up nicely and the following summer was very wet with a big deluge about January 8, 1897.
The widespread rain over western Western Australia at present will not reach us because of the blocking pattern.
It will be well into June before the next rain arrives.