This swell will be generated by a deep low centred around 50S which is expected to track south of Tasmania, with a slight NE wobble as it transits the Tasman on Tuesday. This is a powerful storm, with storm force winds and a large area of seas in excess of 30ft, and as a result swell periods will be in excess of 15s which will produce some real bathymetric focussing effects on deepwater reefs through Wed PM as swell trains get tripped up.
By Mon morning the Tasman sea will be inflamed with severe gale to potentially storm force winds, as a robust low and reinforcing cold front push into the lower Tasman.
Spring starts with pattern change and an unstable, dynamic synoptic outlook with several swell sources incoming.
The surf will continue to fade into the middle of the week ahead of building surf from the east-northeast on the weekend and more so next week.
Current ASCAT (satellite windspeed) passes show our Tasman low in a great place, slowly drifting E of Tasmania towards New Zealand, maintaining a nice pressure gradient squeeze with a high pressure cell SE of Tasmania. As expected, the low has filled in a bit, with a corresponding lessening of windspeeds, mostly low end gales, compared to the storm force winds of it’s “bombing” phase.
The Tasman low finally moves into better position later Thurs into Fri, weakening as it does so. The weekend still looks great though, just smaller due to the declining windspeeds on the SW flank of the low, compared to Monday’s notes.
The weekend's extremely warm, benign weather is about to be swept away by a wintry blast as a trough following the passage of a cold front later today interacts with a cold pool and forms an explosive surface low Tuesday morning.
Not much joy for the weekend but we'll see the surf ramp up rapidly through next week as a Tasman Low develops right off the southern NSW coast.
Next week looks really active now, with a few different swell sources in the offing and a fair bit of model divergence which we will need to resolve on Friday.
Gales exiting Bass Strait today will see a first pulse of weaker refracted S swell early tomorrow but the real juice is being generated by a deeper fetch of severe gales tracking from 55S up to 40S, into the Tasman sea through today and early tomorrow.