A tropical low which hived off the monsoon trough and which has been providing days of chunky E swell to sub-tropical regions is now, finally, on the move. Compared to model runs the system has been much more slow moving than f/cast- which is delaying the arrival of stronger E/NE swell to temperate NSW.

A dual-centred high straddles New Zealand with an elongated monsoonal low pressure trough located in the Coral Sea and extending into the near South Pacific. This is creating a long and broad E’ly fetch which is slowly extending southwards. As we near the end of the week, a more discrete surface low hives off the end of the monsoonal low pressure trough and retrogrades back into the Tasman Sea as it intensifies, generating large E’ly swells over the last days of 2022 and first days of 2023.

The broad pattern will be setting up by Boxing Day with a dominant, slow moving high in the Tasman and low pressure expected to form along the monsoon trough line in the Coral Sea and in the South Pacific near the North Island. That will see at least dual swell producing fetches aimed at the Eastern Seaboard.

Pressure gradients will now slowly ease as the low starts to dissipate and the strong high weakens as it moves South of Tasmania through tomorrow. As this swell generating pattern breaks down we’ll be left with a weak, troughy pattern coming into the Xmas weekend with no major swell sources on hand, so you’ll need to get your grovel boards ready for Santa.