Weather forecasters are warning north coast residents to expect more hail and lightning this summer storm season.
The Bureau of Meteorology says storms have been characterised by heavy rain over the past two years because of La Nina weather pattern.
Forecaster Mike Logan said the swing towards El Nino will cause more violent storms across the region this year.
He said so far it has been a relatively slow start to the storm season.
"But we are starting to see more storm activity," he said.
"I think we're into the season now and really the storm risk is just going to increase over the next month or two.
"So we really need to start to be pretty vigilant.
"It is the time of year when large hail and damaging winds can certainly be a real player with the storms."
The Bureau of Meteorology said hail and lightning are also linked to the increasing El Nino weather pattern.
Mr Logan says the north coast has experienced heavy rain from September onwards over the past two years.
He said the risk period for severe storms will peak over the next two months and locals need to be prepared.
"I think most people in the north east of NSW are a little bit calibrated to the fact that they get some pretty decent storms up there each year," he said.
"But it certainly doesn't hurt just to remember that that is the case, we are into that period now.
"There are things that you can do ahead of time that will definitely put you in a better position if something comes through at fairly short notice."
© ABC 2012
06:32 EDT Flash flooding has inundated homes in the Port Macquarie and Camden Haven area on the mid-north coast of New South Wales.