A fairly active pattern of weather is expected to unfold this week across the east with a deepening trough moving through without much fanfare from WA into the NT on Saturday, now starting to show itself as it moves closer into the moisture that is sitting over QLD, being drawn in via those easterly winds. This pattern has been repeated a number of times this year and continues to offer further flooding potential for the east and through southeast areas of the QLD with rainfall chances also increasing for NSW as well.

Heavy rainfall leading to flash flooding is the main concern as is riverine flooding, but the risk of severe thunderstorms developing closer to the upper low during next week also needs to be watched.

Over the southwest and west of QLD near the upper low, severe storms may form, which would be capable of producing large hail, damaging winds and torrential rainfall. There is a low-end risk of tornado activity. This will peak mid week before the system moves to the east.

For NSW, the rainfall should start to drift south from Tuesday night and increase during Wednesday and Thursday before spreading further south and becoming more patchy as the system weakens and the upper ridge starts to take hold. But over far northern and northeast areas of the state, we need to watch the threat of flooding emerging as we track a very deep moisture plume capable of producing heavy rainfall for northern and northeast areas.

The rainfall is likely to drift further south but it is unlikely to be heavy at this time for southern and southeast areas of the state with a ridge holding firm to the southeast of the state.

Conditions should begin to ease from the west and north in QLD from Thursday and clear the state of severe weather later Friday and that should be the same case for NSW.

Lets take a look


NSW into SA.

The upper low is likely to produce strong to severe storms over eastern SA into northwestern NSW and through southwest QLD. Strong to severe slow-moving storms may produce flash flooding, large to giant hail and damaging winds. A tornado or two is not impossible but the risk is low. Heavy rainfall could lead to some areas seeing 100mm in a few hours due to slow storm motion. Large hail accumulation is also possible. Areas of rain shearing off the storm complexes will move southwards from a line from Cockburm through Dubbo to Taree northwards leading to some moderate to heavy rainfall leading to flash flooding in some locations. Heavy rainfall in onshore winds near a trough could lead to intense flash flooding and riverine flooding developing over the northeast inland of NSW and about coastal areas where some locations could see 300mm. If the storms are more aggressive than forecast, it is possible some areas see 500mm in a number of days. This would include disaster zones from previous flood events.


Widespread rain and thunderstorms developing a long a trough anchored over the Great Dividing Range from inland of Cairns to the NSW border will be the focal point for heavy rainfall leading to flash and riverine flooding. Some locations could see 300-500mm in the course of the week, possibly more about the wet areas exposed to an unstable northeasterly flow. The rainfall leading to a significant flood risk. Inland, widespread rain and thunderstorms will likely continue with more scattered heavy falls. Some areas here could see 3-5 months' worth of rainfall. Flooding is also a relatively broad risk but will come down to where storms form, so stay close to rainfall totals in your catchments. Highest risk for severe flooding from storms is in the Channel Country close to the upper low and centre of circulation.

More on this coming up on Sunday.

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