The weather is expected to turn more active from Wednesday with widespread showers and thunderstorms likely to develop near a trough that will once again deepen, bringing the risk of heavy rainfall and damaging winds to parts of SA, VIC, NSW and QLD as this slow moving trough moves through.

Some areas within the path of this trough could see a months worth of rainfall again on the back of severe weather over the weekend just gone so more unseasonal rainfall chances.

Up across northern Australia, the weather is expected to turn widespread over much of the tropics with that rainfall extending further south as the monsoon trough deepens and slowly tracks southwards. Heavy rainfall leading to areas of flooding is possible throughout the interior.

For the west, not much love in terms of rainfall, the southwest is hot and dry for now but the weather will become more humid and unsettled over the central and northern interior with the rainfall grading more widespread clearly over the tropics.

This weekend, the thunderstorm risk may continue for NSW, ACT and QLD with severe weather chances relating to further heavy rainfall is possible. Next week, there may be another strong trough passing through southern and eastern parts of the nation with heavy rainfall leading to further flooding possible.

That system may then flush the humidity out of the south and southeast.

Lets take a look


Rainfall Next 10 Days

The weather forecast remains fairly low confidence over southern and eastern areas of the nation with the speed of the trough and the depth of the trough moving through the southeast and east of the nation remaining very tricky to forecast this week and into the weekend. Where the trough lingers over the east will determine the heavier rainfall for VIC, NSW and QLD. That is being modelled poorly. The monsoon trough over the north driving heavy rainfall with local flooding remains of high confidence. The above average rainfall will descend further south over much of Central Australia and into western QLD with the chance of further flooding. The weather will remain very unsettled through the coming 10 days over much of the interior and through northern Australia. Some of that moisture over northern Australia may begin to drift southwards across WA later on in the outlook period. Finally, the weather in the medium term, which I will touch on later, offers very poor guidance. Some modelling has some very big weather events over the east and southeast while others have high pressure system and stable weather for the same locations.

Thunderstorm Forecast Tuesday

Heavy rainfall associated with thunderstorms may turn intense over far northwest NSW and eastern SA as well as much of southern NT and into the east of the northern interior of WA. Thunderstorms may deliver more than 50mm in quick time on saturated ground. For the remainder, more thunderstorms developing for VIC and NSW with a trough moving into the west of these states. An upper trough may see showers and storms develop very late over inland SA. And the tropical north being under the influence of the monsoon will likely see gusty heavy storms and flash flooding.

Thunderstorm Forecast Wednesday

Thunderstorms becoming more widespread mid week as the trough amplifies over much of the southeast. Dangerous thunderstorms with life threatening flash flooding resulting from intense rainfall a risk through much of northeast SA and into southwest QLD and the southeast of the NT. Thunderstorms with heavy rainfall and damaging winds extending into VIC and NSW. Monsoonal squalls and heavy falls for the northern tropics.

Thunderstorm Forecast Thursday

Thunderstorms will continue along and to the east of a slow moving trough over the central and eastern parts of the nation. Thunderstorms will carry the moderate to high chance of severe weather, with heavy rainfall leading to flash flooding the main concern. There may be damaging winds over northern parts of the nation with squalls rushing into the western coastal areas. The storms will clear out of southeast and eastern SA later in the day.

Severe Weather Watch - Severe thunderstorms

The severe thunderstorm risk continues tomorrow but through mid week with the trough amplifying through the region bringing up the chance of severe weather relating to flash flooding once again over areas that have seen more than 200mm. The risk may persist over the northeast and northern areas through the weekend,. but clear the south by the end of the week.

The severe weather watch for severe thunderstorms will be reviewed again tonight, but for now the risk is for Victoria Wednesday through Friday with the slow moving trough and this may be extended into Saturday and Sunday for eastern VIC and much of interior NSW where the trough stalls out.

Severe Weather Potential - Wednesday through Saturday

Severe weather is possible from around Wednesday or Thursday across western and northern districts of Victoria with storms likely to carry the threat of heavy rainfall leading to flash flooding. With the very high humidity values, thunderstorms will be efficient rainfall producers across the state. The highest risk will be found over northern, western and central areas. The risk may persist into the weekend over northern and eastern areas as the trough stalls out and follow up charts may be produced in light of that signal.

Severe weather potential - Monday through Friday

The risk will continue daily for western and southwest areas with flash flooding the major concern. Areas of heavy rainfall developing with the monsoon trough moving southwards and merging with the southern trough will see riverine flooding become a concern for outback communities with areas cut off for days/weeks possible. The thunderstorm risk will advise eastwards gradually through the weekend and the thunderstorm risk will be reviewed and new charts issued mid week for that if that looks to be a moderate to major event.

Flooding over the majority of NT is of concern this week with clusters of severe thunderstorms, heavy rainfall and gusty winds with the monsoon trough up north and the trough over central and southern areas merging to produce above average rainfall.

Flood Watch Central and Northern Australia

Heavy monsoonal rainfall this week over the north will see some river systems head into minor flooding. Minor flooding may also redevelop in areas impacted by the remains of Tiffany a fortnight ago and the heavy rainfall over recent days. Some areas over the southeast and central NT have observed 200-300mm this week.

Flood Watch Northwest WA

Heavy rainfall of 200-300mm this week could see minor flooding redevelop in areas that were impacted by the remains of Tiffany a fortnight ago. May have to extend the flood risk further south through the northern and central interior if the tropical low moves through the region and will review later today.

Tropical Depression Watch

The risk of tropical depression formation remains very high on land but over the open water as well this week and so will be watching closely. Two areas that carry the highest risk are over Cape York towards the Gulf and over the Kimberly, both systems remaining over land right now. The system gathering pace is the tropical low over the NT and then moving west into northern WA and that system shifting southwest through the state.

DATA - Refer to the video for GFS analysis and your daily run through.

12Z Euro - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

The pressure pattern is largely unchanged from last night with the only element that is moving around from run to run, the tropical low out of WA which may move through the western and southwest interior with widespread rainfall being drawn into the central and southern interior of WA. That will mean some rainfall and thunderstorm activity will be moving into areas that have been rain free for the past two months. The weather is likely to remain unsettled over much of the nation through the weekend and into next week with uneven distribution of rainfall. The monsoon up north driving heavy rainfall with outback flooding risk. The east coast may see showers but not as much as previous weeks with a ridge running up the NSW and QLD coasts.

12Z Euro - Precipitable Water Values - Next 10 Days

The moisture profile remains very deep across large parts of the nation through to the weekend with the moisture moving out of the southern states across the weekend but briefly, likely to return once again from next week in easterly winds and the monsoon trough way south of where it should be. A tropical low over the west may take moisture and rainfall into the western interior and possibly into southwest WA which would produce the better chances of rainfall since November for the region so will watch that element. Otherwise the nation is looking unsettled and soupy with showers and thunderstorms for the next 10 days with southern areas of the nation possibly seeing a reprieve over the weekend into early next week before the humidity returns with the tropical afternoon downpours returning.

12Z Euro - Rainfall Accumulation - Next 10 Days

Refer to video for more information.

12Z CMC - Rainfall Accumulation - Next 10 Days

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12Z GFS - Rainfall Accumulation - Next 10 Days

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12Z Euro - Rainfall Accumulation - Next 15 Days

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12Z GFS - Rainfall Accumulation - Next 16 Days

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More weather information on the updated 6 week outlook with details on this wet phase and whether it is strengthening or weakening.