BROLLY weather is back in the southeast, with falls in Brisbane and surrounds of up to 70mm expected today.
But it comes as long-term forecasters warn that the rain-bearing La Nina conditions of the past two years may be replaced by a drought-causing El Nino event.
Records show that after a two-year La Nina, an El Nino or neutral conditions will follow, 70 per cent of the time.
National Climate Centre meteorologist Andrew Watkins said the bureau had modelled current conditions 30 times.
"None of the models are going for a La Nina,'' Dr Watkins said.
"They are all going for either neutral conditions or hedging towards El Nino.
"We are assessing our modelling against world modelling and will come up with a position on Wednesday. An El Nino can't be ruled out.''
Despite the predicted long-term drier conditions, Dr Watkins said the chances of receiving above-median rain in April to June were up to 75 per cent for southeast Queensland and the border areas in northeast NSW.
Damper conditions will continue in the short term due to a natural lag as the atmosphere gradually dries. Weather Bureau forecaster Rick Threlfall said falls of 30mm to 50mm would be widespread in the southeast today, but storms could almost double that in some areas.
"We've got a high-level low and there's not much wind up there to push it around, so any thunderstorms will likely be slow moving and sit in the same place for a while,'' he said.
"These will be in isolated pockets but maybe will produce falls to 70mm.''
Showers are forecast to continue through the week, from the Wide Bay region to the Darling Downs and NSW, with heavier falls on Friday.