The 50.2mm of rain, received on Wednesday night at this location, was just above its previous wettest December days in 2017 and 1988.

Using the former town site records, which go back to 1858, Wednesday night's deluge was the wettest December day since 56.6mm on December 4, 1954.

The main feature on the synoptic surface weather charts for the past week has been the presence of a very strong high-pressure system, which resulted in Melbourne's highest barometric reading, of 1030.1 mbs, for the month of December in 160 years.

Past records show there were 14 occasions in December when the barometer rose above 1027 mbs.

Most of these did lead to above normal warmth for the rest of the summer and then continued well into March in North East Victoria.

As far as rainfall is concerned, the heaviest rains tended to arrive two to four weeks after each episode of very high barometer readings in Melbourne.

The autumn and winter rainfall in Victoria after these episodes were notably wetter than average. I expect this to happen in 2021 and again in 2022.

A lot of damage was done to property at Murwillimbah, which had a record daily fall of 225mm for December on the 13th.

At Lismore, a record 481mm for December to date has been set.

The very strong high-pressure has advected a very humid north-east to east wind airstream into Victoria.

Dew point temperatures in North East Victoria, late Wednesday afternoon, reached 21 degrees at Wangaratta, 22 degrees at Albury, Rutherglen and Yarrawonga. During the big deluge at Lismore, the dew point temperatures were also around 22 degrees.

By a remarkable contrast, Portland in South West Victoria had 10mm rainfall and one of its coldest December days on record, with a temperature of only 15 degrees, compared with low 30s in North East Victoria.