Eastern Tasmanian Forecast by Steve Shearer (issued Fri Sep 20th)

Features of the Forecast (tl;dr)

• S groundswell wrap to 2-3ft Sat , easing back Sun
• Minor N’ly windswell Sun
• Gusty W-NW winds continue over the weekend
• Minor N’ly windswell Mon
• S swell spike Wed
• More S swell Thurs easing Fri
• Low confidence in outlook next weekend due to dynamic synoptic, check back Mon

Recap

Tiny blends of NE windswell and S swell yesterday to 1-2ft with fresh NW-W winds. Size has eased off this morning with minor swells to 1-1.5ft and mod/fresh W tending NW winds. S swells to 2-3ft are filling in through the day.

This weekend and next week (Sep20 - Sep 27)

No change to the wind outlook for the weekend- zonal fronts and weak high pressure to the west and well out in the Coral Sea supply W’ly ridging across Tasmania so more mod/fresh W tending NW winds across the weekend with minor S swells.

Surf-wise we’re looking at S groundswell wrap Sat with 3ft sets at S facing beaches, tiny elsewhere.

That swell eases into Sun with some 1-23ft leftovers early and minor N’ly windswell wrap to 1-1.5ft expected.

Into next week and we see another strong front push through Bass Strait Sun into Mon with strong to gale force W-NW winds Mon, tending more W/SW-SW in the a’noon. We should see some N’ly windswell from NW gales out of Bass Strait to 2ft during the day. 

By Tues we’ll see high pressure sliding into the Tasman with winds shifting N’ly and freshening in the a’noon. Small S swells from the front passing under the state Mon to 2ft with some NE windswell likely to build in the a’noon.

Another strong front and polar low passes to the south Wed with winds shifting back W then SW-S as the front passes. That front should see a spike in mid period S swell to 2-3ft in the a’noon.

Further ahead and a front and  trough then brings a more dynamic pattern into the second half of next week. We should see early offshore W-SW’ly winds Thurs with a mix of NE and S swells to 2-3ft. From there the trough deepens and moves Northwards, backed by a strong front in the lower Tasman and a large high in the Bight (see below). The combination of those elements strongly suggests a  surge in S swell Thurs, with freshening SW-S winds. We’ll pencil in a build to 3ft Thurs PM and see how it looks on Mon.

Model divergence reduces confidence in the outlook with GFS suggesting the trough deepens into a broad surface low  which would be too far north to deliver surf to NETas.

ECMWF prognosis features a less dynamic outlook with the trough moving north and dissipating into the end of the week with the high pressure dominating the Tasman by the weekend, bringing an E tending strong NE flow through this period and building NE windswell into next weekend.

We’ll flag a dynamic outlook for later next week and see how it looks on Mon.

Seeya then and have a great weekend!