Some towns on the New South Wales coast and ranges are at risk of getting a shower or thunderstorm each day from now until early next week.
The atmosphere over the area is becoming more humid and unstable with help from a low pressure trough moving back and forth over the region. The wavering trough won't move too far away at any time, giving some places a chance of some rainfall each day for seven days.
The most likely area for this to happen is in and around Grafton, Lismore and Coffs Harbour.
Any thunderstorm that develops has potential to be severe.
Initially, storms are unlikely to bring much rainfall. Large hail will be the most likely severe feature with help from a cold upper atmosphere.
From Wednesday and Thursday damaging winds become more of a chance as a jetstream strengthens over the region. Thursday should be the quietest day due to the atmosphere heating up.
From Friday there is an increased risk of flash flooding, damaging winds and large hail due to growing moisture, a strengthening jetstream and cooling air.
Places which end up underneath some of the biggest storms are likely to pick up more than 50mm between now and early next week with potential for near 100mm.
The west and the south of the state will be much drier due to a more stable high pressure ridge over the region most of the time.
© Weatherzone 2012
21:32 EDT Severe thunderstorms and damaging winds have caused chaos across Sydney, with the SES looking at more than 500 jobs, mainly roof damage from heavy rain and strong winds.