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Brisbane's wettest day in half a century

Tropical Cyclone Alfred was downgraded to a tropical low on Saturday morning, but extremely heavy rain associated with the system has continued to lash Brisbane and surrounding areas, with Brisbane registering its wettest day in 51 years to 9am Monday.

• A huge total of 275.2mm accumulated in the gauge in the 24 hours to 9am Monday.
• That made it Brisbane's wettest 24-hour period since 314mm fell in the 24 hours to 9am on January 26, 1974 – the year of the devastating Brisbane River floods in the wake of Tropical Cyclone Wanda.
• It was Brisbane’s 5th-wettest day on record. The heaviest rain day in the city was January 21, 1887, with 465.1mm.
• It was Brisbane's second-heaviest March rainfall day on record, and the heaviest since 1908.
• Brisbane's total accumulated rainfall since last Wednesday was 466.6mm as at 9am Monday, March 10.
• Brisbane's average March rainfall is 132.9mm, so around three-and-a-half times the average March rainfall has already fallen.

Image: Not since the terrible floods of 1974 has Brisbane seen a wetter day.

Brisbane has of course not been alone in copping extremely heavy rain in recent days.

As expected, the heaviest falls from this system have occurred on elevated areas near the coast, such as the Springbrook Plateau in the Gold Coast hinterland, where more than 1100mm has fallen over the past five days – more than Brisbane's entire annual average rainfall.

But Brisbane itself still received extremely heavy and persistent rainfall over the weekend and into Monday morning, as the city happened to be situated in the convergence zone – the area where winds from two different directions come together, forcing air to rise and causing a focused area of intense rain.

Image: The convergence zone is illustrated in this six-hour radar loop to midnight (AEST), a period in which Brisbane received 92mm of rain as the bands of heavy rain (green and yellow on the radar) appeared to continually replenish themselves.

The good news for sodden Brisbane locals is that heavy rain is expected to ease this afternoon, with showers on the cards for the rest of the week rather than persistent rain.

But the immediate situation remains extremely serious across significant parts of southeast Queensland and northeast NSW. Numerous flood warnings are in place, as well as multiple emergency warnings from NSW and Qld authorities.

Please check the Qld Government Disaster Management page or the NSW SES page for the latest emergency warnings.