The NSW State Emergency Service is prepared for an increase in storm activity, with severe weather expected in many areas.
Afternoon storms are likely on Wednesday in the west and far south of the state including the Riverina.
On Thursday widespread and potentially severe storms with heavy rain, damaging winds and large hail is possible in many parts of the state including Western NSW, Sydney, Mid North Coast, parts of the Hunter and Illawarra.
From Friday through to Sunday widespread moderate to heavy rain is expected in many areas as a rain band moves into eastern parts of the state.
NSW SES State Duty Commander, acting Assistant Commissioner Greg Swindells said now was the time for people to prepare.
"Ahead of the onset of bad weather take small steps to prepare yourselves and your families," he said.
"Clear your gutters, trim trees and bushes away from properties and move your vehicles away from trees and powerlines.
"Put away or tie down loose items so they don't get blown around in the wind."
With heavy rainfall there is a chance of flash, localised riverine and creek flooding.
Assistant Commissioner Swindells said flash flooding and water over roads can occur very quickly and without warning.
"Monitor conditions in your area and avoid driving during heavy rain," he said.
"Never drive, ride, walk or play in flooded roads. You should also avoid camping near creeks and rivers."
For the latest information and warnings visit ses.nsw.gov.au or download the Hazards Near Me App.
For help during floods, storm and tsunami call the NSW SES on 132 500 or in life threatening situations call Triple Zero (000).
