Inland Low to Threaten Queensland Deluge as Positive SAM Bites

March 22, 2025

EC accumulated rainfall during the next 10 days showing heavy rainfall across large areas of western to northern Queensland. Source: Weatherwatch MetCentre.

Queenslanders are unlikely to see much reprieve from severe weather this week, as another low-pressure system is set to dump heavy rain across large areas of the state—particularly western to central Queensland, with the potential for impacts to extend into northern and central eastern parts later in the week.

March Still Means Wet Season

In a timely reminder that March is still very much part of the wet season, a slow-moving upper trough is forecast to strengthen a trough over western Queensland into a surface low.

This developing system will draw in deep tropical moisture from the north, while also tapping into a broad easterly fetch across Queensland and the Coral Sea—a setup driven by the current positive SAM (Southern Annular Mode).

A very dominant band of easterly winds will help feed moisture into the system. Note the westerly wind belt is well south, lying south of Tasmania. Source: Weatherwatch MetCentre.

The positive SAM has temporarily weakened the westerlies that would typically push through cold fronts and dry out moisture, allowing this widespread humid pattern to linger.

Potential for Major Flooding

Due to the slow-moving nature of the system, several days of moderate to heavy rainfall are expected across western Queensland, bringing the potential for major flooding next week.

MetGraph showing multi-model rainfall totals near Winton and Cloncurry in outback Queensland. Source: Weatherwatch MetCentre.

Later in the week, a high in the Tasman is expected to push the system northwards, which could cause heavier rainfall to contract into northern and central eastern Queensland, including the Herbert and Lower Burdekin—regions that have already faced multiple flood events this season.

EC Precipitable water showing that the main band of moisture may contract into northern Queensland later next week. Source: Weatherwatch MetCentre.

Townsville, for instance, recorded 301mm earlier this week—its wettest March day since 1997—after already experiencing major flooding in early February.

Southeast QLD Misses the Worst—for Now

While the populated southeast is not currently expected to experience heavy rainfall from this system, its presence is still likely to bring increased cloud, light rain, and showery conditions into the region, especially during the first half of next week, resulting in some gloomy days. We will continue to monitor this for change - in the short term, some isolated showers and storms could occur over the weekend and as they'll be slow moving there is the low risk of some localised flash flooding.

EC CAPE showing areas of instability across NE NSW & SE QLD today. This may bring some local moderate falls due to slow moving storm activity, but localised pockets of hail and strong winds cannot be ruled out for the ranges (particularly across northeastern NSW). Source: Weatherwatch MetCentre.

With multiple days of rainfall expected, residents and tourists in western and central Queensland should monitor forecasts closely and begin preparing for possible road closures or isolation due to flooding.

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