Eastern Tasmanian Forecast by Steve Shearer (issued Fri July 25th)

Features of the Forecast (tl;dr)

• Small fun E/NE swell persists Tues/Wed
• Small S swell Tues, easing Wed AM before kicking again PM
• SW winds Tues, tending S’ly
• S’ly winds persist Wed
• Easing S swells Thurs
• Long period S swell wrap Fri
• Small swells this weekend
• Possible NE windswell episode Mon
• Good quality E/NE groundswell likely next week from intense low in Tasman, building Tues PM, peaking Wed
• Still a way away so check back Wed for latest updates

Recap

Large stormy NE swells Sat cleaned up and held in the 6ft range on Sun. Today offered clean 4ft surf from the E/NE-NE with offshore winds.

This week and next week (Jul 28- Aug8)

High pressure is up over sub-tropical NSW, drifting into the Tasman and a massive low which swept up over the SE of the continent is now moving SE of Tasmania without showing too much in the way of swell generating winds for the east coast. A retreating broad trade fetch feeding into a trough is still supplying small E’ly swells. As mentioned on Fri- we’ve got an unstable atmosphere expected over the Tasman this week with an inland surface low pressure modelled to move into the Tasman mid week before moving away swiftly to the east. Over the weekend there’s now growing agreement on a coastal low (possibly some variant of an ECL) to form off the NENSW or SEQLD coast and intensify as it moves into the Tasman, with potential for severe weather and sizey swells. There’ll be plenty of revisions as we move closer to this event so we’ll outline it today and tighten the focus as we move through the week.

In the short run troughs related to the current decaying low SE of Tasmania generate bands of W-SW winds across NSW and adjacent to  Tasmania. That will see SW tending S’ly winds at fresh paces and a flush of short period S swell reaching 3-4ft at S facing beaches but of low quality. Small E-E/NE swells will continue to offer 2 ft sets, similar into Wed.

S swells ease through Wed AM before kicking again in the a’noon to 3ft with winds staying fresh S’ly as a strong high pressure ridge fill in behind the trough. Expect mostly low quality stuff. 

By Thurs we’ll see these local S swells ease off and winds ease from the S. Still 2-3ft early easing through the day with E swell still offering some 2-3ft sets. 

Back up from the S on Fri as a long period S swell wraps in from a polar low passing the lower Tasman earlier in the week. Winds shift more W’ly through the day and sets will show to 3-4ft at S facing beaches through the a’noon.

Not much over the weekend justly decreasing S swells Sat, becoming tiny on Sun.

Next week looks more interesting. 

We’re likely to see an episode of N-NE windswell Mon as an approaching front tightens the pressure gradient with a high being squeezed in the Tasman by a sub-tropical low. 

That low looks to be a monster of a system. As the deep low moves eastwards towards the North Island (see below)  it aims up gales to severe gales back towards the east coast and we’re on track to receive some powerful swell from the E/NE through next week. 

Source of E/NE groundswell next week

That looks to offer some real size and quality up again in the 6 occ. 8ft range with bigger sets possible on Wed with swells first showing Tues a’noon.

High pressure should be drifting over NSW during this time suggesting NWW winds.  

Still a lot of water to go under the bridge before we get there - so expect revisions when we come back Wed. 

Seeya then.