December 27, 2024
Last year, SE QLD and NE NSW endured repeated days of destructive storms over the Christmas period. Fortunately, this Christmas brought sunny, warm, and stable weather—but that’s set to change in the coming days.
Changing Weather Patterns - Cold Fronts Return
The shift in weather is due to increased cold frontal activity across southeastern Australia. For much of November and December, persistent easterly winds brought high humidity and scattered showers to Queensland while pushing severe summer storms inland. However, stronger cold fronts over the next 5–7 days will drive the main surface trough closer to the east coast, where it will collide with the humid northeast flow, creating stronger instability and an elevated threat of showers and storms. This will also allow for cooler air to occur in the upper atmosphere - aiding in instability.
MetGraph for Brisbane showing the 300mb temperatures which are likely to fall be between 6 and 8C over the coming days thanks to the cooler air in the upper atmosphere which will aid in generating instability. Source: MetCentre
Storm Risks Today: Central Eastern and Northeastern NSW
Today, most storm activity will focus on central eastern and northeastern NSW, where very hot temperatures—reaching into the low 40s in parts of the Hunter and western Sydney—will combine with elevated instability. These conditions are likely to support damaging wind gusts, with a smaller chance of large hail.
EC CAPE & G3 rainfall showing instability and precipitation potential today. Source: MetCentre
Sydney could experience strong wind gusts in storms, but the highest risk is likely just north, in the Hunter region.
Forecast maximum temperatures for NSW & Sydney today. Source: MetCentre
Southerly Change Brings Relief to NSW - Contracts Storms into NE NSE / SE QLD
A gusty southerly change tomorrow will cool large parts of NSW and push a trough into Queensland, triggering showers and storms in central inland and southeastern Queensland, as well as northeastern NSW. Temperatures in Southeast Queensland could locally approach 40°C, with the primary threat being damaging wind gusts.
Forecast maximum temperatures for QLD & Brisbane today. Source: MetCentre
For Brisbane, storm activity is most likely during the evening if it occurs but the main concern will be south and west of Brisbane. Unlike recent storms that caused flash flooding, tomorrow’s storms are less likely to bring widespread heavy rainfall. However, large hail could occur in isolated areas, although the high temperatures may melt hailstones before they reach the ground.
EC CAPE & G3 rainfall showing instability and precipitation potential tomorrow showing storm potential favouring the Northern Rivers and Southeast Coast, but broadly extending northward also. Source: MetCentre
ACCESS sounding showing moderately levels of instability and supportive wind shear for severe storms in parts of SE QLD tomorrow. Source: MetCentre
Sunday: More Storms But Outlook Becomes Less Certain
On Sunday, a stronger cap may limit storm development in the Southeast Coast but could allow storms to form further north, in regions such as the Wide Bay & Burnett. Severe storms remain a possibility, though the risk is expected to be more isolated.
EC CAPE & G3 rainfall showing instability and precipitation potential on Sunday. Activity may favour areas north of the more populated Southeast Coast, though if storms occur in the Southeast Coast there is a reasonable chance they could be severe thanks to the increased levels of instability. Source: MetCentre
Monday: Potential Weak RCT Setup in the Darling Downs
Monday could see a weak Ridge Cradled Trough (RCT) setup in the Darling Downs, which often produces supercells due to strong low-level wind shear. However, mid-level wind shear appears weaker in this instance, which might reduce the intensity of these storms. Nonetheless Monday appears to be a day of interest for inland areas of Southeastern Queensland.
EC CAPE & G3 rainfall showing instability and precipitation potential on Monday - activity may favour areas inland from the more populated Southeast Coast region. Source: MetCentre
ACCESS sounding showing a classic, deep NE wind shear into a trough however mid-level wind shear is currently lacking to make this a more volatile setup. Source: MetCentre
A Complex Outlook for New Year's Eve & New Year's Day.
From early to mid-next week, a broad area of cool air is expected to combine with a humid E/NE flow. This pattern will likely continue the trend of showers and storms, though the severe storm risk may shift to flash flooding concerns. Current indications suggest a humid, showery and potentially thundery day for both New Year's Eve and New Year's Day, even in Brisbane.
Multi-day storm periods are notoriously difficult to forecast, as each day’s activity influences the next through remnant outflow boundaries and atmospheric changes. While the forecast may shift day-to-day, the main metropolitan areas should largely escape severe storm impacts until early next week, when flash flood risks could emerge.
More showery and thundery conditions could occur on Tuesday and Wednesday with high levels of moisture and slow moving activity possibly re-introducing some flash flood risks. Source: MetCentre
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