QLD - WIDESPREAD SHOWERS AND THUNDERSTORMS REDEVELOPING FOR THE EASTERN COAST LATER THIS WEEK.

The inland has dried out and should remain fairly dry overall in comparison to previous weeks, with more ridging and drier air being trapped into the region over the coming 4-5 days.


Another trough over the south of the state is likely to sharpen through the next couple of days, invigorated by an upper low which is situated over NSW. This will add more wind shear and dynamic support for heavier convection to form.


Another upper low is expected to develop over the inland of NSW over the weekend and this could once again lead to an enhanced risk of severe thunderstorms with heavy rainfall rather than a long drawn out rain event for the state. So we transition to a severe storm outbreak.


For the north, the rainfall is looking a little below average at the moment with onshore trade winds weakening and the forecast MJO from last week that was due to pass through, now looking more likely to bypass to the north of the state so looking at a period of build up conditions again.


Lets take a look at the latest details.

FORECAST

Rainfall Next 10 Days

Rainfall is forecast to remain very much over eastern third of the state as we see a clean out of the instability, not the humidity, from the interior of the state. With a reduced monsoonal impact over northern areas of the state, this is expected to lead to less influence for the remainder of the state in terms of follow up rainfall. Some areas have missed out in recent weeks, Central QLD and pockets of the Tropics and I am anticipating these areas to continue to miss out under the current guidance. The rainfall over the eastern third from the Great Dividing Range to the coast will be scattered and uneven in distribution but the coverage more widespread over the SE QLD region where flash flooding may become an issue this weekend again.

Thunderstorm Forecast Wednesday

Thunderstorms are forecast once again on Wednesday, mainly for areas on and east of the Great Dividing Range where wind convergence develops through the afternoon and evening. Slow storm motion will lead to some storms dropping significant rainfall totals in quick time of saturated land. The biggest risk for flash flooding is in the southeast of QLD during the afternoon and evening but more likely in NSW. Scattered storms over the tropics will remain near seasonal in terms of coverage but the rainfall has been a little below average of late.

HEADS UP SEVERE WEATHER THREAT

Another low pressure system in the upper levels is forecast to approach VIC and NSW this weekend and run into a deep moisture profile and easterly winds. Scattered to widespread showers and thunderstorms are likely to develop with those turning severe through VIC on Friday afternoon with a band of heavy thundery rainfall leading to flash flooding. Then the storm risk breaks out over northern VIC through NSW into southern QLD this weekend with dangerous thunderstorm activity possible with all modes of severe weather possible including giant hail and destructive winds (tornado activity) over parts of the east. Heavy rainfall also looks set to redevelop along the coast with intense rainfall rates but determining who is in line for that remains to be seen so stay weather aware.

DATA - Refer to video for more information and for the daily run down


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

There is more analysis in the video, but the areas of concern to watch have been well forecast ahead of time, and we will start to see them unfolding now. So that being the flood event for the NSW coast and adjacent inland, the approach and passage of TC Anika and the severe weather potential for inland areas with flooding. We may see another wave of low pressure in the upper levels on Friday drive severe weather for eastern SA, VIC, NSW/ACT and southern QLD this weekend with follow up severe storms. The remainder of the nation away from the southeast, east and northwest looking at seasonal conditions. In the medium term you can see the impacts of the positive SAM phase.

00Z GFS - Precipitable Water Values - Next 2 Weeks

The very deep moisture profile is expected to dominate for the coming week over the northwest and over the east and southeast with a dynamic atmosphere in both locations leading to the above average rainfall. Elsewhere, the drier air is planted firmly over the southwest of the nation and in pockets of central and eastern inland areas on the backside of low pressure moving through the east. The pattern may begin to shift in the medium term but at this stage, it looks like the models are keen to keep the easterly wind bias in place.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to video for more details

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to video for more details

A closer look in - severe storms will produce further flash flooding for the severe weather impact zones over the course of the next week in the east.

More coming up tonight with a look at all things modelling and rainfall after 9pm EDT.


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