As models update and we draw closer to the storms it has the potential to be very nasty even dangerous.
The best I can do is post the ABC article with the link. It has been very well written to explain the synopsis of this system.
https://www.abc.net.au/n...christmas-2023/103257550Violent thunderstorms are likely across eastern Australia this Christmas, rivalling some of the most intense and widespread storm outbreaks of the past few decades.
The spell of explosive thunderstorms will result from an unusual weather pattern in late December — polar air currently escaping from Antarctica will drift directly over south-east states from Christmas Eve to Boxing Day.
Two children, a boy and a girl, play in muddy waters in Western Queensland
Parts of Australia have seen widespread flooding, bushfires and a tropical cyclone in recent days.(Supplied: Tara Rule)
The arrival of a wintery air mass in a hostile summertime environment will create an exceptionally volatile atmosphere, capable of producing severe thunderstorms from northern Queensland to southern Victoria.
While severe storms are not ideal for Christmas, it's still a more favourable forecast than widespread flooding, bushfires or a tropical cyclone.
Storm potential nearing theoretical maximum
Thunderstorms develop when warm, moist air sits below cold air, and the set-up of polar air drifting over high temperatures and humidity up and down the eastern seaboard is the perfect recipe for a major storm outbreak.
a graph of southeast australia shows a pool of cold polar air sweeping across
A pool of cold polar air will drift over southeast Australia this Christmas. (ABC News)
One measure of storm potential is called Convective Available Potential Energy (CAPE), and the higher the CAPE, the more energy is available for a thunderstorms to grow.
During a standard Australian storm day, CAPE can often reach about 500 to 1,000.
However, modelling of CAPE for this Christmas is forecast to reach up to about 3,000, comparable to instability seen during infamously destructive storm outbreaks across the US plains — the most severe storm-prone region on Earth.
Another consequence of the out of season cold pool will be an
Jetstream forecast expected to enhance thunderstorms
The jet above eastern Australia will further enhance storm intensity, generating organised long-lasting thunderstorms and a high likelihood of supercells, the most dangerous storm type which can produce giant hail and destructive winds.
Storms growing in intensity through weekend
The storm zone today will include most of inland NSW and Queensland, although most storms should remain below the severe intensity.
Saturday forecast rain
Thunderstorms will develop over much of eastern Australia tomorrow.(ABC News)
The peak of the event will arrive from Christmas Eve when the polar air mass and jet arrive.
Tomorrow is likely to produce severe storms across much of Queensland, including Brisbane and northern NSW, possibly down to about Sydney.
While the skies are lighting up for Santa's arrival in the north, further south a developing low-pressure system — as a result of the polar air aloft — will cause areas of heavy rain with embedded storms over southern NSW and parts of Victoria.
a weather map of australia show where rain will fall along eastern australia
Severe thunderstorms and heavy rain are likely across much of eastern Australia on Christmas Eve.(ABC News)
Severe Christmas Day storms for eastern capitals
Widespread severe storms will then continue through Christmas Day from tropical Queensland to the Victorian coastline, and have the potential to bring flash flooding, hail and damaging winds to Australia's most populated stretch of coastline.
All eastern capitals could potentially see severe weather from thunderstorms on Christmas Day, and would be rated as a high chance in Brisbane, Sydney, and Canberra.
a weather map of forecast rain along eatern australian states for monday 25 december
A wet and stormy Christmas is forecast for eastern states.(ABC news)
While the most explosive storms impact Queensland and northern NSW, the heaviest rain should fall over Victoria and southern NSW, and areas of localised flooding could even develop into Boxing Day, although for now widespread major river flooding is unlikely.
Severe thunderstorms will continue to impact many parts of eastern Australia on Boxing Day before the polar air mass retreats into the Tasman Sea from Wednesday.
The stormy Christmas will ensure a wet finish to 2023, with an average of 20 to 100 millimetres of rain across the east during the next four days.
Up to 100mm of rain expected along east coast
Complicating the rain forecast is powerful thunderstorms which often produce hyperlocal rain bullseyes, and in some cases well over 50mm could fall in just a few hours.
On the opposite side of the spectrum, areas which happen to lie between storms may only receive a few millimetres
