Prosper in a dynamic world
Search

Massive swell arriving this weekend

A Tasman Low pressure system will whip up large and powerful swell for several days from Saturday, with the potential to impact port operations along the eastern seaboard.  

The images below show that a stubborn high-pressure system will cradle the low and keep it over the Tasman Sea between Saturday and Wednesday.  

 Images (top to bottom): Mean Sea Level Pressure (showing the low in the Tasman Sea marked with an ‘L’) together with 24-hour precipitation on Saturday, June 15, Monday, June 16, and Wednesday June 17. 

The low will generate fierce winds along coastal areas of NSW, Vic and Tas between Saturday, June 15 and Wednesday, June 19. The image below shows that the low will strengthen further on Sunday, with the potential for gale force winds to impact the waters off the NSW, Vic and Tas coasts. 

Image: 10-metre instantaneous wind gusts at 4pm AEST on Sunday, June 16, according to Access-G. 

While the winds should ease below gales on Monday, they will continue to be strong through till Wednesday. 

The stubborn Tasman low will generate a long fetch, meaning these tireless southerly winds will move over a large swath of open water causing large waves to impact the coast for several days. 

The swell will build over the weekend, before easing in the middle of next week. However, there is potential for the low to linger over the Tasman until Friday, June 21, continuously pumping massive swell towards the east coast. 

The images below show significant wave heights reaching 4 to 6 metres during this period, with the potential for 6-8 metres off the Vic, Tas and southern NSW coastline on Sunday.  

 Images (top to bottom): Significant wave heights at 4pm AEST between Sunday and Wednesday, June 19, according to Wave Watch III.  

These large waves will also be powerful with the wave period potentially reaching 13 to 16 seconds. 

The wave period is the time between successive wave crests or troughs. The longer the time, the greater the energy is within the wave. Wave periods over 11 seconds are associated with stronger waves.  

The wave height and period expected over the coming days has the potential to impact port operations along eastern Australia. These large and powerful waves should cause coastal erosion along southern facing beaches in NSW, Vic and Tas. Dangerous surf warnings will likely be issued, so keep an eye out for the latest warnings.  

DTN APAC offers a comprehensive suite of services, refined through years of collaboration with the marine, ports and offshore industries, to optimise the safety and efficiency of your operations.

We work with you to understand your intrinsic operational challenges and customise high-precision forecasting, metocean and aviation services to your exact location and operational scope.

When working offshore, our solutions can underpin planning and safe execution for offshore oil and gas enterprises and wind farms. Our data can support your exploration, development, rig moving, shuttle tanker operations, and production and decommissioning phases. Whether your crews are on-site, being transported to shore, or diving to perform maintenance, we deliver tailored weather risk briefings to ensure you choose the optimal time to proceed.

Weatherzone’s trusted nowcasting and forecasting system, OpticastTM, allows you to rapidly respond to changing conditions offshore, en route and in port. We take your port topography and berth orientation into account, ensuring site-specific forecasts. For offshore oil & gas, wind farms, ports and logistics, we have your weather situational awareness covered, no matter where you are. We deliver real-time severe weather and lightning alerts to your team via your integrated dashboard: Portzone, and our Weatherguard app.

Weatherzone’s Total Lightning Network (TLN) ensures you avoid hours of unnecessary downtime by providing the most accurate technology in lightning detection and alerting. Safeguard your teams and assets with lighting and Dangerous Thunderstorm Alerts (DTAs), customised to your existing parameters and delivered in real-time across all devices in your network. You gain full spatial awareness of developing severe weather systems, allowing you to plan ahead and, where needed, execute your shutdown and evacuation procedures.

With extreme conditions slowing production and affecting infrastructure, safety and transport, trust us to deliver Australia’s most precise weather data and tailored insight, giving you decisive confidence when it’s most needed. For more information please contact us at apac.sales@dtn.com.

Latest news

Satisfy your weather obsession with these news headlines from around the nation, and the world.

How does DTN help businesses monitor bushfire induced pyrocumulonimbus thunderstorms that ignite more fires?

Intense heat from bushfires during elevated fire danger days can trigger fire-induced pyrocumulonimbus thunderstorms that ignite additional fires. In early January 2026, an extreme heatwave sweeping over southeastern Australia brought catastrophic fire danger to Victoria. Intensely hot bush and grass fires spread erratically and quickly in hot, dry and gusty winds, with pyrocumulonimbus generating lightning, […]

Active seas to the north and east of Australia disrupting port and maritime operations

Seas to the north and east of Australia are experiencing periods of increased activity this week, leading to disruptions to port, maritime and offshore operations. Intense and hazardous Tasman Sea Ocean conditions across NSW’s South Coast rapidly deteriorated last Friday as a deep feed of easterly winds whipped up large and dangerous seas. The Batemans […]

Transport, emergency and energy industries flooded across Greater Sydney with weekend deluges

Transport, emergency, energy and port industries in eastern NSW and Sydney were impacted by significant flash flooding with intense and heavy rainfall this weekend. Rainfall rates between 80 and 140mm in one to three hours were registered across parts of Sydney’s Northern Beaches and Central Coast on Saturday afternoon and evening. In some areas, these […]

DTN Dangerous Thunderstorm Alerts in action with severe thunderstorms disrupting Perth industries

Severe thunderstorms impacted southwest WA and the Perth region on Sunday, December 14, 2025, triggering Dangerous Thunderstorm Alerts (DTA) by DTN for industries and businesses in the region. DTN operates Dangerous Thunderstorm Alerts (DTA) which alert businesses and industries to thunderstorms based on intensity and movement. These alerts provide advanced notice of thunderstorms moving into […]