On Thursday afternoon, annual rainfall at the Sydney Observatory overtook the city's annual record of 2194mm, set more than 70 years ago in 1950.

More than 58mm of rain fell at the Sydney Observatory between 9am and 2pm on Thursday, data from the Bureau of Meteorology revealed, as severe weather continues to wreak havoc across NSW.

Australia has entered its third consecutive La Nina, and with more rainfall expected and nearly three months of the year to go, Sydney is likely to decimate the record set in 1950.

Flood warnings are in place across NSW, Victoria and QLD as Eastern Australia bears the brunt of days of drenching rain, filling already-flooded inland rivers.

A Weatherzone spokesperson said NSW would be the hardest hit state by thunderstorms this week as a trough and low pressure system moves across the states.

Earlier this week, the Bureau of Meteorology issued severe weather warnings for parts of NSW, Queensland, Victoria, the ACT and Tasmania, and Australians are unlikely to get a reprieve from wet weather until Monday, a Weatherzone spokesperson told ACM.

On Tuesday, NSW SES Commissioner Carlene York APM said the weather would be another challenge for many communities who have been flooding for close to a year now.

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Flood warnings are current for the Macquarie River, near Bathurst in NSW's Central West, and with a wet weekend ahead for the Bathurst 1000 racing event, SES volunteers are preparing for a busy weekend, SES Commissioner Carlene York said on Tuesday.

"We are preparing for possible flooding along the Macquarie River - and with Bathurst shaping up for a wet weekend it is important people take steps to stay safe," she said.