Submitted by Craig on Fri, 03/21/2014 - 11:38
South Australian Forecast (issued Friday 21st March)
Best Days: Saturday morning in protected locations down South for keen surfers, Thursday morning, Friday morning
Yesterday was great across both coasts with an easing SW groundswell from 1-2ft on the Mid Coast and generally 3-5ft across the South Coast with offshore winds. Conditions remained clean down South into the early afternoon before a weak sea breeze kicked in.
Early this morning a trough drifted in from the west, bringing a strong onshore change to the region with poor choppy 3-4ft waves across the South Coast and choppy 1ft waves across the Mid Coast.
A small windswell has since kicked up on the Mid with the S'ly winds to 2ft, while the South Coast is also see a junky windswell developing.
This weekend (Mar 22 - 23)
There's plenty of swell on the cards for the weekend but the fly in the ointment will be the local winds.
The swell will be unfortunately too south for the Mid Coast, which will be cleanest, while protected locations will offer the best waves Saturday morning with a morning E/SE breeze. Size wise, the swell should provide 3-4ft+ waves across the Middleton stretch with 4-5ft sets at Waits and Parsons.
A considerable drop in size will be seen into Sunday but winds will be poor and from the S/SW.
Next week onwards (Mar 23 onwards)
As touched on last update, after a couple of pulses of medium sized S/SW groundswell through Monday-Thursday next week, we'll see a good week at least, if not longer of suppressed swell activity and small waves.
This will be related to a strong upper level block moves in from the west and sets up across the Bight.
Similar to the way the Long Wave Trough steers frontal systems up and into us when it's positioned across the south-east of the country, an upper level block will steer frontal systems away from us, suppressing storms and swell activity. This is illustrated in the diagram to the right.
But this will only take effect after we see a couple of medium sized S/SW groundswell pulses through early to mid next week (with one final pulse of S/SW groundswell on the cards for Thursday).
Winds will unfortunately be average Monday and fresh from the S/SE, but winds will tend more E/SE into Tuesday and Wednesday before swinging NE into Thursday and Friday favouring protected spots across the South Coast.
The Mid will unfortunately be tiny to flat with the southerly direction of the swells being blocked by Kangaroo Island.
Longer term, into next weekend and the following week, as explained above, the blocking weather pattern will keep swell activity to a minimum resulting in small waves best suited to exposed spots across the state. Winds look generally favourable though and from the NE.