BoM has warned of a dangerous and potentially life-threatening situation for the south east today and into the next 48 hours.
A spokesperson said any rain that falls would renew river rises, and creeks would rise very quickly.
Premier Annastacia Palaszczuk said it was a very concerning time.
"These are unprecedented times," she said in a press conference.
"I have lived in Brisbane all my life and I haven't seen storms and floods like this all being thrown at us at once."
The Bureau is warning of dangerous storms for the northern Moreton Bay region, Sunshine Coast and Fraser Coast.
Unstable weather conditions are expected to continue throughout today.
As a precaution, parents should be collecting children from school when it is safe to do so.
At Grantham in the Lockyer Valley, people who have just started returning to their flooded homes and businesses after being inundated last week are once again hearing a flood siren.
Lockyer Valley Regional Council has issued an emergency alert for Grantham, advising flash flooding may occur in the Grantham area and water levels may rise quickly.
Residents are being asked to relocate to family or friends in a safe area until conditions settle and to warn others.
There are indications that water levels in and around Grantham could rise fairly rapidly today (starting this morning) and close exit routes.
Police will be conducting a door knock.
If you need assistance to move anyone from the house (disability, aged and frail), please contact SES on 132 500.
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