NSW/QLD - SEVERE WEATHER UPDATE - LATEST INFORMATION - THURSDAY 30TH JUNE.

ANALYSIS - THURSDAY 30TH JUNE 2022 10AM EST.


THURSDAY

A band of rain is currently developing through QLD on with moderate falls developing later in the day. This extends back into the NT with moderate falls also possible. An upper low over the southeast inland will drive a few showers over SA and VIC and showers will also develop over inland NSW through the afternoon and evening with the bulk of the rainfall found in the Central and Southern Inland but the falls hit and miss, this mainly this evening and overnight. Showers developing along the east coast of NSW with some moderate falls possible along the coastal fringe from Sydney to Narooma from later tonight into Friday morning.


FRIDAY

Friday, the rain increases further with moderate to heavy falls developing from Mt Isa through to Longreach and southeast into the Great Dividing Range. Some areas could see 2-3 months of rain in a day. Showers increasing over the coastal areas of NSW with further moderate to heavy falls developing along the coast with local thunder. Pinning that down is tricky but anywhere from Newcastle to Narooma needs to watch the forecast still with a bullseye around Wollongong appearing on some of the modelling. Showers over the inland of NSW with that spreading through to the ACT and Riverina during the evening with moderate rainfall possible overnight into Saturday. Drier weather developing over the southeast.


SATURDAY

Saturday, rain with local thunderstorms with moderate to heavy falls over QLD contracting south and east through the day. Some very heavy falls possible about parts of the QLD coast from Mackay through to Hervey Bay. Showers turning to periods of rain along parts of the NSW coast mainly south of Newcastle with an upper low remaining slow moving. Some very heavy falls are possible about the South Coast and Central Coast of NSW. Periods of rain under the upper low with moderate falls possible but the rainfall not uniform.


SUNDAY

Sunday, rain and local thunderstorms with moderate to heavy falls over eastern QLD remaining slow moving as a trough becomes stationary from inland of Cape York, through the FNQ, Capricornia and Central QLD coasts and this will extend into the Wide Bay and Burnett later in the day. Some areas could see very heavy falls along the coastal fringe. Rain periods under an upper low over inland NSW, mainly on and to the west of the Great Dividing Range with patchier falls over the southern inland but dry in the far west. Heavy to very heavy rainfall possible IF we see a deepening surface form offshore the Central Coast. There may also be the risk of damaging winds as well along the coast if this does indeed develop.


MONDAY

Monday, rain and local thunderstorms continues over parts of eastern QLD with some moderate to heavy falls about the Capricornia and extending southwards to the Wide Bay and Burnett with a slow-moving trough. Rain and strong winds for the NSW coast with a trough and deepening low pressure system driving the severe weather risks, mainly south of Sydney at this time with showers and moderate falls further north. Rain over inland NSW begins to clear eastwards as the upper low weakens.


TUESDAY

Tuesday, rain and local thunderstorms may begin to contract eastwards and clear during the afternoon along the QLD coast, but some modelling suggests that the rain may linger for a while longer over the NSW coast with another low-pressure system running southwest down the coast with moderate to heavy rainfall continuing.


SEVERE WEATHER WATCH - QLD

The risk zone for severe weather is unchanged from Wednesday, with the trough over the interior driving up the chance of moderate to heavy rainfall and the coverage of that heavy rainfall could see riverine flooding develop. Also with the high rainfall rates, flash flooding is also a risk. The risk of riverine flooding is highest along the QLD coast from the Mackay region southwards to about the Sunshine Coast at this time. The focus of the riverine flooding builds later in the weekend into early next week along the coast.

FLASH FLOOD RISK - QLD

Pockets of heavy rainfall is expected to feature along a sharp surface trough combining with deep moisture and this is leading to widespread rain but embedded in that will be some heavier convection leading to those locally intense rainfall rates. A moderate to high risk of this unfolding throughout the interior during Friday through Saturday and along the coast from Saturday through Tuesday. Clearance of the severe weather risk dependent on the movement of the trough to the east with a secondary upper low likely to form over the inland early next week which could keep the rain in place until mid week.

RIVERINE FLOOD RISK - QLD

A low risk of riverine flooding for the inland and a moderate to high chance along some of the coastal catchments in response to heavy rainfall developing near a stationary trough from the weekend and into next week, the risk may be increased further to very high in the coming days if the guidance becomes more supportive of heavy rainfall with the secondary trough sharpening over the east coast from Mackay through to Hervey Bay during Monday into Tuesday.

SEVERE WEATHER WATCH - NSW

An upper low is moving into NSW today and remain slow moving over the interior from Friday and into the weekend, leading to showers over the inland. But the upper low will help to draw in deep moisture from the north and east with a trough forming along the coast. It will be this trough that increases the risk of severe weather over parts of the NSW coast from Friday and then persisting through the weekend with the risk of high impact flash flooding with the slow-moving areas of heavy rainfall near the coast and then damaging winds developing in the presence of a surface low during the latter part of the weekend and into early next week. Also watching the heavy rainfall threat spilling south from QLD into northeast NSW later in the weekend and heavy rainfall in pockets under the upper low over the inland.

FLASH FLOOD RISK - NSW

Flash flooding is a high risk at this stage, could easily lift it to very high chance over parts of the coast from Wollongong to Narooma with a trough on Friday night into Saturday and over the Northern Rivers and then extending up and down the coast this weekend into early next week. A low risk at the moment under an upper low over the inland, particularly Central West during Saturday and Sunday with slow moving areas of rainfall, this may extend towards the Southern Tablelands and Southwest Slopes and ACT, placement of the upper low key. While it has been drier the past 2 weeks or so, be aware that it won't take much to get the runoff going again.

RIVERINE FLOOD RISK - NSW

A moderate to high risk of riverine flooding developing once again along the coast from Narooma northwards with a few pockets where the risk is higher in relation to the topography and shape of the coast and how the trough/low pressure behaves and sets up. Understand that this forecast is a heads up and the risk zones will become more refined as we move forward through the days ahead, but we could see conditions supportive of flooding emerge from Friday night onwards through the weekend and into early next week. With the upper low over the inland we could see 40-50mm in scattered pockets falling over wet ground, it won't take much to get some further peaks down the river systems which are leading

More in the state-based forecasts this evening. Remain weather aware and be across the changes.