The weather has been very active for the past fortnight but we are seeing the back of it in the coming 2 days. As mentioned throughout the past week here, the last of the ECLs would help to pull up dry air from the south and we are set to see that influence increase from later tomorrow through Wednesday, easing the rain and thunderstorms with heavy falls and squally winds.

Western inland parts are settled and dry with sunny skies and that sunny drier weather is expected to spread further east during the coming few days, with a full clearance of the east expected by Friday.

However, the drier weather over the western interior is forecast to come to an end this weekend as a weak trough over QLD beginning to dig in, tapping into some moisture left over to produce showers and thunderstorms about the western and northern interior with the chance of these producing some moderate rainfall. Along the coast, we will not lose the showers altogether, but the coverage should be lighter and more sparse than what we are expecting in the coming days.

Another trough from SA will run into the developing feature over western NSW during the weekend and this will see a substantial band of cloud with areas of rain and thunderstorms developing this time next week, again some moderate rainfall is possible before that trough clears north and east through the state.

Cooler nights are on the way later this week for a brief period and those cooler drier nights will also return in the wake of the system passing through during next week. That is a sign that we are moving into more of Autumnal weather building through the outlook period.

Lets take a look


Rainfall Next 10 Days

Rainfall is expected to remain heavy over the coming 2 days, that is clear for the Mid North, through the Hunter, into the Upper Hunter, Central, Metro, Illawarra and Shoalhaven Coasts and extending through the coastal escarpment into the eastern face of the Tablelands. Some of it could push a little further west over the Central Tablelands. The showers and thunderstorms over the northeast will be more isolated in the coming days with a slow moving trough but that too should move off by Thursday. Once we lose the low later tomorrow, just gusty southeast to southerly winds and showers running parallel to the coast can be expected with dry weather remaining in place for inland areas west of the divide for the next few days. A new trough may emerge through northwest NSW during Friday and linger over the weekend leading to scattered showers and a few storms about. The coverage of thundery weather may increase early next week as a trough approaching from SA runs into the east with modest moisture in place being lifted into another round of rain and thunderstorms. No widespread severe weather is expected beyond the immediate risk along the coast.

Thunderstorm Forecast Tuesday

Thunderstorms are possible near the upper low as it moves to the south off the coast of the Hunter and then moving southeast of Sydney. There is a trailing trough on the northern flank of the system which may spark a few showers and thunderstorms over the northern inland and across the central and northern inland tomorrow but no severe weather is expected. Thunderstorms about coastal areas through Hunter down to about Wollongong could be severe overnight and during Tuesday with damaging winds, heavy rainfall leading to flash flooding and the risk of a weak tornado/waterspout.

Flash Flood Risk Monday into Tuesday

Heavy rainfall is ongoing and the risk of flooding is now focussed in on the Upper Hunter, through the Central Coast region of NSW down to about Wollongong. The flash flood risk will extend inland to the coastal ranges and maybe the Blue Mountains, especially from about Linden eastwards.

A closer look in on those disaster zones!

Damaging Winds Risk Monday into Tuesday

Damaging winds near to the south of a low pressure system developing near the NSW coast, around Gosford, is forecast to see tree damage become quite a feature overnight and during Tuesday. A brief isolated tornado or waterspout near the coast cannot be ruled out.

DATA - Refer to video for more details and model analysis and context behind the forecasts above.

00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

The severe weather risks for the east should begin to ease on Tuesday as the low pressure system over the Tasman deepens into a surface low and moves east. The winds and showers persisting through the week but the rainfall intensity coming down. Storms will contract into QLD through this week with the risk of severe thunderstorms still relatively elevated. Across the remainder of the nation it is looking fairly benign with only a handful of showers and storms over in WA along the central and northwest coast. The weather over the tropics seasonal. Temperature wise, hot to very hot in the west, grading to warm to hot in SA but milder along the coast and into the southeast and eastern inland where conditions will remain below average over the east coast. Hot and very humid for the north with routine showers and storms about.

00Z GFS - Precipitable Water Values - Next 2 Weeks

Moisture values are coming down for parts of the eastern and southeast inland which has been well documented here for a while. Moisture will increase over northern and western Australia with moisture being pulled in from the jet stream which is running over the Indian Ocean. The moisture over NSW will contract further east and northeast into QLD and that is where it should stay until it is reintroduced into inland QLD and NSW this weekend and into next week. Moisture from the west will spread through SA and into the southeast inland and eastern inland next week. That will see rainfall chances come back up.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to video for more on the rainfall accumulation and model assessment.

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to video for more on the rainfall accumulation and model assessment.

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to video for more on the rainfall accumulation and model assessment.

A closer look in - refer to the video for my analysis on the state based look. There may be some agencies and ideas on the board that are fixed on statistics about where places will be dry and others not so dry, the overall trend is for low confidence forecasting until we get the upper low off the board in the east.

More coming up from 8am EDT tomorrow. I will resume the models and rainfall outlooks from tomorrow night once we lose the east coast low event and see what we are looking for in the medium term. I will have the 6 week climate outlook as well.

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