Brisbane is "unlikely" to see destructive winds with Cyclone Alfred forecast to weaken to a category one system as it moves across Moreton Bay islands on Saturday morning.

Ex-Tropical Cyclone Alfred has been downgraded to a tropical low and is currently sitting off Bribie Island, moving slowly north.

As a sudden rain bomb smashed through Hervey Bay in the early hours of Sunday morning, many residents were left wondering what had happened – and why they didn’t have more notice of what was to come.

South East Queensland and northern NSW are in it for the long haul with ex-Tropical Cyclone Alfred, forecasters have warned, with severe weather and flood warnings still in place for large parts of the east coast.

Tropical Cyclone Alfred has slowed its approach and is now expected to cross the south-east Queensland coast on Friday afternoon.

The Bureau of Meteorology has issued a bleak reminder Tropical Cyclone Alfred could intensify to category 3 as the storm heads towards Brisbane.

Residents in Cyclone Alfred’s danger zone have been warned they only have hours to escape, while there are fears an entire coastal city in northern NSW will be inundated with water.

Tropical Cyclone Alfred is located 560 km east of Brisbane and the Sunshine Coast and gale force winds are expected to develop over the next 24 to 48 hours along widespread moderate to major flooding say the Bureau of Meteorology.

The Bureau of Meteorology has been accused of failing to warn Hervey Bay of severe storms that dumped more than 300mm of rain on the coastal community, causing flash flooding and a string of swiftwater rescues.

Authorities are telling residents to prepare now for wet, windy and wild weather — including potential flash flooding — from Wednesday till the weekend.