Coastal Low To Bring Heavy Falls to NSW Coastline - Isolated Storms to NE NSW / SE QLD with Hail Risk

Weatherwatch
Apr 27
3 min read

April 27, 2025

ACCESS 500mb temperatures showing a strong upper cold pool of air is tracking into northeastern NSW which has developed a low off the NSW coastline and may bring storms to NE NSW & SE QLD.

An upper low is tracking across northern NSW and has induced a small low off the Hunter Coastline this morning. This will generate moderate to heavy falls along the central NSW coastline while bringing the chance of some isolated storms to SE QLD & NE NSW with the risk of hail (particularly in NE NSW).

Heavy Rainfall, Possible Gales for Central NSW

A small low can be seen tracking to the SW along the Hunter coastline this morning.

A small low is tracking southwest along the Hunter coastline this morning. This is driving onshore easterly winds into a cool upper atmosphere, helping to bring moderate to heavy falls today. Falls of 60-120mm are possible across parts of the Hunter, with moderate falls extending towards Sydney and the Mid North Coast where totals of 40-80mm are possible, particularly favouring areas close to the coastline.

EC rainfall to 10am Monday showing the potential for moderate to heavy falls today.

Winds may also strengthen along the coastline today, with gale force wind gusts possible and localised damaging gusts about exposed parts of the Hunter coastline later today as the low potentially crosses inland. Wind and rain may then ease overnight as a second low develops further offshore, shifting winds from easterly to southerly.

ACCESS C wind gusts showing the progression of a small low (note that wind gusts appear to be over-forecast in this model, but could reach 90-100km/h about the coastal fringes locally).

Storms Possible for NE NSW & SE QLD

The storm setup for NE NSW and SE QLD is a little more complex than usual. Normally when a low develops off the NSW coastline, it pushes drier westerly winds inland, eroding the potential for storm activity. However, with today's low tracking westwards and potentially moving over land, the onset of drier air will be delayed.

Surface winds & LIS and surface winds & dew points. Despite the drier westerly winds, instability will still be present across NE NSW and then to a lesser degree, SE QLD.

Meanwhile, the axis of the main upper cold pool will track into northeastern NSW. The combination of delayed drying and enhanced upper-level cooling should be sufficient to generate a few showers and storms across NE NSW. Thanks to the colder upper atmosphere, hail is a notable risk in any storms that do form.

Forecast sounding for the Northern Tablelands showing some instability thanks to the cold air in the upper atmosphere from the upper cold cool despite the drying trend.

Lower Risk Further North into Southeast Queensland

Further north into Southeast Queensland, afternoon showers and possibly very isolated storms may develop. However, the hail risk will diminish quickly moving northwards away from the border. This is due to the warmer upper atmosphere and greater distance from the upper low's influence.

Moisture Will Be Key to Today's Storm Potential

As is often the case with meandering low pressure systems, confidence is a little lower today:

If moisture levels hold higher than expected, there could be greater storm and hail activity than initially forecast.
If westerly winds advance faster, the atmosphere could stabilise too quickly, reducing the storm risk.

Current satellite imagery suggests enough moisture should linger until at least the early afternoon, keeping the door open for storm development. In other words - the highest chance may be earlier in the afternoon rather than later in the afternoon when the westerly winds become more established. However should any stronger activity occur it will remain quite isolated and be more likely in NE NSW.