Storms to Increase for NSW, Tropical Cyclone Risk Looms in Tropics

January 27, 2025

After a brief respite from severe weather, conditions across Australia are set to intensify again. Last week saw Tropical Cyclone Sean drenching the Pilbara coastline and severe storms delivering everything from giant hail to a tornado in eastern Australia. Unfortunately, the break will be short-lived, with storm activity ramping up across NSW and an elevated tropical cyclone risk emerging in the tropics.

Storms & Severe Potential for NSW

A cold front sweeping through southeastern Australia today will bring scorching temperatures, with Melbourne expected to hit 41°C. Isolated afternoon showers and storms are likely to accompany the front (with the threat of strong winds in this activity), but the main focus will be along a trough in eastern NSW, where storms will bring the potential for damaging winds and large hail. However storms will continue in NSW for some days yet.

ACCESS C temperatures at 4pm in Melbourne showing temperatures in the low 40s, while ACCESS CAPE across NSW suggests sufficient instability for storms across eastern areas (particularly along the ranges). Source: MetCentre

Storms may increase tomorrow as the same cold front nudges into NSW and helps provide increased convergence. While the highest threat of storms tomorrow will once again be just inland, some coastal areas (including Sydney) won't escape the chance of storms with a gusty southerly change likely to provide convergence required to initiate more coastal storm activity also. A combination of high temperatures and slightly drier air approaching from the west will make conditions conducive to the development of damaging wind gusts in particular.

Instability will generate further storm potential across central eastern to northeastern NSW tomorrow bringing the further threat of severe storms.

Mid-week, the trough will stall through northeastern inland NSW and generate several days of showers and storms here with some further localised severe storm threats, but unlike the previous systems the chance of storms should decrease further north into southern Queensland.

ACCESS CAPE supports instability across northeastern inland NSW during Wednesday and Thursday that may maintain the risk of isolated, severe storms. Source: MetCentre

Tropical Cyclone: A Likely Threat, but Uncertain Position

A mix of ensemble and global member forecasts indicating very poor alignment in tropical cyclone positioning and direction of systems. As such, while the chance of a system developing is high (>50%), where the system will develop remains uncertain. Source: MetCentre

Across the northern tropics, westerly winds from an active MJO pulse will collide with the trade easterlies, generating increased shower and storm activity. This pattern is conducive to the development of low-pressure systems, particularly in the Gulf of Carpentaria and the Coral Sea.

• Late this week onwards: At least one of these lows is likely to develop into a tropical cyclone. However, forecast models show significant variation, with each predicting different locations and tracks for the system. While the likelihood of a tropical cyclone is high, confidence remains low regarding its exact timing and location. Expect this to continue - each model run is sometimes shifting the position of these lows by nearly 1000km! For this reason, it’s important not to focus on daily fluctuations in forecasts with better alignment between models expected later this week.

  
  
  
  
  

  

  

  GFS, ACCESS and EC forecasts of the position of a tropical cyclone early next week showing differing scenarios. Source: MetCentre

  
  

• Short-term impacts: A small low and associated trough system north of Townsville will bring higher rainfall potential to the northeastern Queensland tropics. Moderate to heavy falls are possible between Cairns and Townsville, with Australian models predicting heavier rain than their international counterparts.

Small low to the north of Townsville will bring increased convergence across northeastern Queensland that will bring the potential for some moderate to heavy falls over the coming days.

Comparison between EC, ACCESS and GFS forecast rainfall across northeastern Queensland. While there is significant variation, patterns appear conducive for some moderate to heavy falls along with an elevated flash flood risk over the coming days between Townsville and Cairns. Source: MetCentre

With the peak of the tropical cyclone season approaching, residents and businesses in tropical cyclone-prone areas should remain vigilant. Be sure to monitor updates and always ensure your emergency weather kit is up to date!

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