Eastern Tasmanian Forecast by Steve Shearer (issued Wed Aug 28th)

Features of the Forecast (tl;dr)

• Larger  NE windswell Fri  easing into the weekend from gales out of Bass Strait
• Gusty NW winds continue all week, with W’ly periods
• Strong and gusty W-NW winds continue over the weekend
• Stronger S swell Tues next week from front pushing up into the Tasman

Recap

Small levels of NE windswell yesterday were in the 1-2ft range, a notch bigger today in the 2ft range with gusty NW-W winds.

This week and next week (Aug 28 - Sep 6)

No change to the pattern with very strong, zonal frontal activity below the continent driving strong to gale force W’lies across the immediate Southern Ocean into Bass Strait and the Tasman. Weak, mobile high pressure is being pushed quickly into sub-tropical latitudes. The gale force fetches out of Bass Strait are supplying small S’ly pulses favouring Central/Mid North NSW with pre-frontal N/NW-NW winds supplying N’ly wind swells to NETas. 

In the short run we’ll see the current severe gales out of Bass Strait (60kt gusts recorded at Hogan Island!) lead to tiny N’ly windswells tomorrow with size to 1-2ft and fresh/strong W’ly winds easing and tending N/NW in the a’noon.

The more N’ly tilt in winds across Bass Strait later tomorrow and o/night into Fri (see below) should lead to another burst in N’ly windswell for Fri with the morning seeing size to 3-4ft under fresh gusty N’ly tending NW winds.

More N'ly fetch o/night Thurs see plenty of N'ly windswell into Fri morning

Same again for Sat but with winds tending more gusty W’ly we’ll see size ease to 2-3ft then 2ft during the day.

Size then eases further into Sun with more gusty W’ly tending NW’ly winds.

Into next week and it looks like a less zonal, better aligned fetch moving into the Tasman early next week (see below). Still with W’ly biased winds but they will have a S’ly component. Under current modelling we’d see fresh NW tending W’ly winds Mon, with winds shifting W/SW-SW as a front and low pass into the Tasman. We’ll finesse the timing and size Fri (EC still has a much more bullish outlook than GFS) but at this stage we’re looking at small surf to start Mon before an a’noon increase looks likely, possibly up into the 2-3ft range.

Swells then build Tues into the 3-4ft range with SW winds shifting back W-W/NW as the day goes on.

That swell looks to tail off quickly into Wed and we’re back to small surf for the rest of the week with some minor NE windswell possible.

There is some suggestion of a pattern change by next weekend with a more favourably positioned long wave trough steering a stronger front into the Tasman (bringing a stronger S swell) and a supporting high moving at a more S’ly latitude. That’s too far off too have any confidence in but we’ll flag it for now and see how it looks on Fri.

Seeya then!