Flooding has hit central Brisbane after a massive rainstorm this afternoon.
Police are warning motorists are advised to avoid areas of Fortitude Valley due to local flooding.

The areas currently affected are McLachan Street, Constance Street Gilbert Street and surrounding areas.

Water is believed to be at bonnet level in some areas and traffic is at a standstill coming off the Ivory Street Tunnel.

The weather pattern is expected to dump more than 50mm of rain across parts of the city, continuing the incredible run of rain for 2008 that is filling the southeast's dams.

An astonishing two-and-a-half months supply of water fell in the states dams overnight, leaving the combined storage capacity at more than 31.5 per cent.

A severe weather warning was issued just before 8am this morning for the Darling Downs and Granite Belt, which the Bureau of Meteorology expects to produce damaging winds, very heavy rainfall, flash flooding and large hailstones.

Residents in those areas have been warned to move cars under cover and away from trees, secure loose objects and beware of fallen trees and powerlines.

The same system will cross Brisbane some time after midday or early afternoon.

"We know there's going to be severe weather today," senior meteorologist Vikash Prasad said.

"Thunderstorms will develop around lunchtime. They have the potential to dump a large amount of rainfall in a very short period of time.

"And because the ground is already saturated, it really can't take any more without significant run-off."

About 32mm of rain fell in Wivenhoe while Somerset and North Pine dams had 15mm and 8mm respectively.

The dams have been inundated with an extra 12 months of water in 2008 alone, as predicted by long range forecaster Haydon Walker last year.

The overall supply now stands at 31.53 per cent.

Rain and flash floods have inundated and damage many roads around the central coast and the state's south-east corner in the past few days.

The tourists towns of Agnes Water and 1770 are cut off with bridges over creeks and flood-ways under by water.

On the Gold Coast yesterday, a 15m section of road collapsed on the Isle of Capri.

Flooding has also closed the intersection of the Brisbane Valley Highway and Esk Kilcoy Road at Harlin, near Esk.

But the D'aguilar Highway at Kilcoy, northwest of Brisbane, was this morning reopened to all traffic expect wide loads.

The highway to Kilcoy was cut in two places overnight due to water flowing over the Sheep Station Creek and Kilcoy Creek bridges.

There were also storms reported in the Maranoa, Warrego, Granite Belt and Darling Downs regions.

Flood warnings have been issued for numerous rivers and creeks, including the Lockyer, Bremer, Warrill and Brisbane River below