A high pressure ridge has combined with an offshore trough, generating heavy showers and storms over the northern NSW and southern QLD coasts across the past two days.
These have produced widespread accumulated falls of 100mm across the Sunshine Coast over the last two days, with some parts picking up over 200mm. Coolum West has collected the most rainfall in the area so far with 238mm.
Further south falls have been lighter with 30-80mm across the Gold Coast and northern NSW, with only 10-20mm around Brisbane. Today isolated slow-moving thunderstorms have produced 60mm in Kingscliff on the northern NSW coast, with 30mm of this falling in just 30 minutes. Another thunderstorm to the south also produced a waterspout at Cabarita Beach.
Showers and isolated storms are expected to become even more frequent from this evening and into Monday as a coastal trough deepens, before a low develops later on Monday or early on Tuesday.
This is likely to produce further heavy falls across the region with widespread totals of 70-120mm. The Sunshine Coast and Hinterland is likely to see the heaviest falls from the system, with falls in excess of 200mm possible. Winds may also increase, with gusts to 80km-90km/h possible on the coast.
Despite the heavy rainfall, falls should not be as great as was seen during Ex-Tropical Cyclone Oswald. However, the rain will still be enough to cause flooding with flood warnings likely to be issued.
The low should move south during Tuesday, contracting showers to the Gold Coast and northern NSW by the evening. By Wednesday conditions should have eased, although a few showers should persist.
© Weatherzone 2013
18:04 EDT The weather bureau has urged residents in Queensland's Gulf to remain on cyclone alert as ex-Tropical Cyclone Gillian moves overland.