Flash flooding has closed roads and stopped trains in New South Wales this morning following giant hail and record rainfall over the weekend.

Flash flooding has led to the partial closure of Industrial Drive at Tighes Hill and trains have stopped on the Hunter line due to the heavy rain.

According to the Bureau of Meteorology, 130 millimetres of rain has fallen at Merewether in the last 24 hours, with 101 millimetres at Broadmeadow and 79 at Waratah.

State Emergency Service personnel are busy clearing more than 360 outstanding jobs today having attended 1475 jobs since 2.30pm on Friday.

Of those, 483 were in the Coffs Harbour and Byron Bay areas, where large hailstones fell on Sunday.

A NSW SES spokeswoman said the service had received 120 calls in the Hunter and Newcastle area this morning.

She said personnel were preparing for a tough 24 hours with the rain system expected to continue through the day.

The storm was expected to peak this morning with the Bureau of Meteorology issuing a severe weather warning for the Sydney metropolitan area as well as the mid north coast.

BOM said to expect gale force winds of up to 90km/h, thunderstorms and rain which may lead to flash flooding.

A flood warning has also been issued for the Paterson and Williams rivers.

In NSW more than 900 calls were made to emergency services over the weekend after storms lashed the coastal areas.

Since 9am yesterday Newcastle has recorded 135 mm of rain, Wiliamtown 127 mm and Tocal 118 mm, with more than 50mm rain expected to fall across the state today.

The weather is expected to begin clearing tonight.

Despite reporting its warmest winter ever, yesterday was NSW’s coldest November day in seven years with a top of just 17.6 degrees.

Today’s weather follows millions of dollars of damage caused by Queenland’s battering on Saturday with hail stones the size of cricket balls hitting the Sunshine Coast.

In coastal NSW, Byron Bay briefly resembled an alpine village instead of a beachside town, the large ice pellets littering its streets.

The insurance industry says it expects the damage bill to run into the millions and it could take weeks to process claims.

Authorities are urging residents living in hard-hit areas to assess the damage immediately.
Hundreds of cars and homes had been damaged, but no major injury reported.

QLD SES volunteers were at a State Emergency Service Week awards night Saturday, with about quarter of the audience forced to leave to attend emergencies.

Queensland Fire and Rescue officer Mark Kelly says the weather bureau correctly forecast dangerous storms with hail, but no-one expected the hail to be so big.

“A lot of the hail has broken rooving skylights and subsequently houses had been flooded by the rain… there are a number of cars that would also be damaged,” he said.

Mr Kelly said emergency services responded to hundreds of calls for help in and around Maroochydore.

-with AAP and ABC