Sydney Airport is in chaos, with passengers experiencing a flow-on effect of delays and cancellations as weather forecasters warn of more storms Friday afternoon and into the weekend.

The Bureau of Meteorology warn of more severe storms for parts of New South Wales as passengers at Sydney airport line-up in long cues in the aftermath of wild weather on Thursday night.

BoM forecaster Jordan Notara told The New Daily heavy rainfall could again hit Sydney, but the probability was lower than warnings for the direct coastal fringe of the city than northeast parts of the state.

Another day of #SevereStorms for parts of #NSW. Majority of storms will be confined to the northeast of the state, though there is a chance we will see some more storms about the central parts of the coastline. Warnings will be issued as storms develop at https://t.co/0nv5XJNXrJ pic.twitter.com/133JCuRo3T

— Bureau of Meteorology, New South Wales (@BOM_NSW) March 15, 2019

“It’s a low probability, but a high impact if it were to occur and it could bring heavy rainfall like what we saw last night [Thursday],” Mr Notara said.

Queues of passengers snaked through Sydney Airport on Friday morning, while airlines warned of domino-effect delays.

At least 10 domestic arrival flights and 10 departures have been cancelled on Friday as well as two cancellations at the international terminal.

It follows more than 40 flight cancellations on Thursday.

Tweets by jbd01

A massive clean-up of branches and debris has been underway in Sydney after severe thunderstorms swept across the city Thursday night, bringing strong winds, giant hail and heavy rainfall.

Volunteers have begun removing branches and clearing storm debris as emergency crews work to restore power to about 8650 homes and businesses across the Illawarra region, Southerland Highlands and Macarthur district.

Very dangerous thunderstorms were detected near Blacktown and Riverstone, the Bureau of Meteorology said on Thursday evening, encouraging people to “bring umbrellas” as the rain is expected to continue for the rest of the week and well into mid next week.

The storms moved east with severe thunderstorms hitting the city and eastern suburbs by nightfall.

More heavy rain is forecast for NSW and Queensland on Friday.

The NSW State Emergency Service responded to more than 620 calls for help overnight across the greater Sydney region and the south coast, with as many as 25,000 homes without power during the thunderstorms.

Images from the city’s west showed golf ball-sized hailstones pummelling cars while almost 20,000 lightning strikes were recorded across the greater Sydney area.

I thought the hail from the first storm was big then the second one came and the hail stones doubled in size, crazy #sydneystorms pic.twitter.com/DsXBSwHVPE

— Lisa (@lisa121078) March 14, 2019

The downpour triggered flash flooding, power outages and more than 350 calls to the rescue service.

Roads, trains and even flights were delayed and diverted away from Sydney’s airports.

Showers are forecast on Saturday extending to northern inland areas while on Sunday showers will likely reach the far northern inland with a chance of thunderstorms in the north.

-With AAP