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Ex-Tropical Cyclone Tam brings huge waves to NSW coast on Good Friday

Source Weatherzone Sat 19 Apr 2025

An ex-tropical cyclone underwent explosive cyclogenesis over the Tasman Sea, generating massive waves sent to the NSW coastline on Good Friday. Tropical Cyclone Tam had a short-lived life as a tropical cyclone this week, but as drier mid-latitude air wrapped around the ex-tropical system, the central pressure of the system rapidly dropped. Through a process called explosive cyclogenesis, the pressure of the system dropped 18hPa in 24 hours, classifying it as a bombing Tasman Low. As seen in the image below, powerful winds reaching 45-50 knots (85-90 km/h) were circulating around the system on Wednesday. Image: ASCAT winds over the Tasman Ocean showing the strips of data collected by the low orbiting satellite. Source: NOAA These winds generated large waves reaching 8-10 metres well in the Tasman Sea. This swell reached Sydney and the NSW coastline overnight into Good Friday, with significant wave heights reaching 4.5-5.5 metres on Friday, April 18. As seen in the images below, surfers were able to surf in Balmoral Beach, well inside the Sydney Harbour. Images: Surfers enjoying the novelty waves deep in the Sydney Harbour at Balmoral Beach. Amazingly, this is the second time in just over two weeks that keen Balmoral surfers have been able to surf the harbour beach. The powerful swell of April 1, 2025 sending swell lines well into the harbour. Outside the harbour’s heads, the ocean beaches were coping a flogging. Huge waves made it impossible for beach goers to get a dip in with otherwise fantastic conditions with a warm and sunny day. Unfortunately, two people have drowned, and one is missing in part, due to the large and unpredictable waves. Images: Huge waves batter the Sydney coastline on Friday, April 18. The swell peaked in the late morning and early afternoon, around the high tide at 11:30am, and conditions are slowly easing across the coast. However, a Hazardous Surf Warning remains in place for the whole NSW coastline on Saturday, April 19. Significant wave heights of 2.5-3 metres on Saturday morning will gradually ease to 2-2.5 metres into the afternoon, and becoming much more manageable on Sunday. Keep up with the latest weather warnings here. - Weatherzone © Weatherzone 2025