Bureau of Meteorology predicts up to 100mm of rain could pelt down around Wollongong this week

Heavy rain has potential to make the UCI race route slippery for cyclists, but sun is expected to shine on the final day of the Road World Championships on Sunday.

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The Bureau of Meteorology is predicting temperatures to remain in the low 20s or high teens, while at this stage thunderstorms could develop on Saturday.

Senior Meteorologist Olenka Duma said a low pressure system was expected to bring widespread rainfall to central and eastern NSW from today, shifting further eastwards on Thursday, before weakening during Friday.

"Wollongong area can expect rain to develop from later this afternoon or evening (Wednesday), persisting throughout Thursday," Ms Duma told the Mercury.

"Whilst the low is expected to move further east and away from the coastline during Friday, showers and possible thunderstorms are expected around Wollongong during Friday and Saturday.

"Five day rainfall totals for the Wollongong area are expected to be around 40-70mm, locally isolated 100mm+, which will be highly dependent on thunderstorm activity in the area. Thursday is expected to be the wettest day this week."

It comes as other parts of the state have been put on flood watch: the Central West Slopes and Plains, Central Tablelands, South West Slopes, Riverina and Lower Western Forecast Districts.

"At the moment, the highest rainfall totals are expected along the northern half of the coast," Ms Duma said.

"Severe Weather Warnings are not expected to affect the Illawarra/Wollongong area, however, as this system develops it's advised to keep abreast of any warnings (both Severe Weather and Flood Warnings/Watches) over the next couple of days."

The Bureau forecast widespread rain to affect western NSW on Tuesday, before extending through central and eastern districts on Wednesday and Thursday.

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"Most of the rain is forecast for Wednesday, and peak rain totals are likely to be comparable to those experienced during last week's rain, although the precise locations may vary," the BOM stated late Tuesday.

"For the coast, there is a higher degree of uncertainty regarding rain amounts, with Thursday and Friday being the main days of interest and dependent on the movement of the low.

"Currently, the northern half of the coast looks to be the wettest on Thursday."

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