Tuesday, 10th September 2024
Yesterday, showers and storms developed over northeastern NSW, but the NSW/QLD border acted as a near-imaginary boundary, with almost no activity extending northward into Queensland. This occurred because storms that developed along the ranges were generally pushed east/southeast by upper-atmosphere winds, preventing them from moving north into Southeast Queensland. Additionally, a band of mid-level moisture stalled across northeastern NSW, initiating much of the storm activity there.
Recorded rainfall yesterday showing very little activity moving north of the NSW/QLD border via the Virtual Rain Gauge Network. Source: Weatherwatch MetCentre
Today, that band of mid-level moisture is expected to extend into Southeast Queensland, likely bringing a few showers and isolated storms. Fortunately, most areas in Southeast Queensland will experience only a few claps of thunder and brief bursts of heavy rain, with severe storms not being a major threat. This is despite the presence of a southeast change—a feature often linked to severe storm development in the region. The reason for the reduced risk is that, being early in the season, the southeast change will bring cooler air and strengthen the "cap"—a small layer of stable air that inhibits storm development.
Satellite imagery showing mid-level showers and moisture streaming across Southeast Queensland & Forecast C3 rainfall for Southeast Queensland today. Source: Weatherwatch MetCentre
However, if storms can survive the transition from mid-level to surface-based, brief bursts of severe activity could occur, as deeper easterly winds in the lower atmosphere increase low-level helicity. The highest chance of this happening will be in the inland areas of the Southeast Coast region, possibly extending into the eastern Darling Downs and southern Wide Bay & Burnett regions.
C3 forecast sounding for inland Southeast Queensland. The low-level easterly flow (10-15 knots) combining with the moderate westerly flow at 500mb (30 knots) can locally enhance storm intensity even in areas of weak instability. Source: Weatherwatch MetCentre
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