Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 6th March)

Best Days: Large surf each day this week 'till Sat, though mainly S'ly winds will confine the best waves ot the points and sheltered southern ends. Lighter winds from Thurs onwards. Strong but easing swells this weekend with light variable winds. 

Recap: Building short range E’ly swells on Saturday ended up being bigger than forecast, though onshore winds created generally miserable surf conditions across much of the coast. Winds swung offshore through Sunday morning at many locations, improving surf conditions as wave heights temporarily abated, ahead of a rebuilding S’ly swell throughout the day. The Tasman Low responsible for the weekend waves clicked into fifth gear overnight and this morning, and surf size today has built far bigger than Friday’s estimates - we’re now seeing solid 6ft+ sets across south facing beaches, and early SW winds are now strong S’ly in most regions.

This week (Mar 7th - 10th)

What a crazy couple of days in synoptic land. 

After holding strong all last week with a sustained forecast for large waves from a slow moving Tasman Low, the wheels came off on Friday with a couple of consecutive downgrades. 

Then, over the weekend, the trend reversed - and now we're looking down the barrel at the biggest and best Tasman groundswells since last June’s Black Nor’easter.

Make no mistake: large, slow moving low pressure systems like this are not common in our neck of the woods. We wish they were, and some years hand them out in droves (see 2007) but they don't always position themselves like this one is suggesting. More times often than not we'll get a day or two of solid surf, with tricky winds. Extended, sizeable runs of swell out of the eastern quadrant just don't happen very often. 

We’re already seeing 6ft+ sets off a small thin (but strong) fetch off the developing low. But over the coming days it’ll broaden across the entire Tasman Sea, and hold easterly gales in position from Tuesday to Friday, with the south-western flank of the low skirting the East Coast of Australia and the south-eastern flank of the low pushing into north-west New Zealand. That's one heck of a sizeable system, and the majority of the associated fetch will be aimed in our general direction.

It’s one of the best looking synoptic charts I have seen for a long time (I was overseas last June; my counsellor advised me to purge that weather event from my memory), so we are looking at a sustained run of large E/SE swell across the entire Eastern Seaboard.

So, on to specifics. 

Today’s swell is currently holding from the S tending S/SE, and through Tuesday we’ll see the swell direction swing from the S/SE to the SE, before tending E/SE through the second half of the week. This means that initially south facing beaches will see the most size, but as the week progresses we’ll see a more uniform size distribution across the coast. 

With the low remaining slow moving, it’ll display a broad supporting fetch around the primary system - generating a strong underlying level of groundswell - but also several embedded fetches of stronger winds which will create a couple of pulses of larger surf. The first is expected throughout Tuesday afternoon into Wednesday morning, with a second, similarly sized pulse late Thursday and into Friday. Surf size may drop a little between these pulses (i.e. with a “low point” around Thursday morning). 

I’m expecting background energy to hold in and around the 6ft mark throughout the week, but the embedded pulses should come in higher than this, around 6-8ft at times. Obviously, sheltered points and protected corners will be smaller though this ratio will tighten up as the swell direction develops more east.

Local winds look like they’ll create some problems over the next few days at open beaches across the Sydney, Hunter and Illawarra coasts, with a fresh to strong S/SE flow. We should see pockets of SW winds early mornings, but this will be confined to just a few locations (the Northern Beaches usually does well under these patterns). Winds should be lighter south of the Illawarra and there’s a greater chance for early SW winds here too.

By Thursday we should start to see a more broader morning offshore pattern with moderate S/SE breezes settling in through the middle of the day, as the lcoal pressure pattern eases. Friday should deliver great conditions will light offshore winds and afternoon sea breezes. 

All in all, this is shaping up to be a long run of sizeable waves. So pace yerself!

This weekend (Mar 11th - 12th)

The Tasman Low is expected to begin weakening on Friday. And with a rough translation time of 1.5-2 days from the eastern Tasman Sea to the Australian East Coast, this means Saturday morning should still be quite sizeable across the coast - though surf size will be easing. 

More importantly, as the low ease it’ll leave a weak pressure gradient across the coastal margin. This means light variable winds, likely all weekend.

Saturday morning should see early 6ft sets across open beaches, with an easing trend to 4-6ft during the day (swell direction should be E/SE, thus a relatively uniform size range at most coasts). A more pronounced easing is expected into Sunday, easing from around 4ft to 2-3ft during the day. 

All in all, it’s shaping up to be one of the better weekends in recent months. Let’s hope this week’s large swells don't create problematic offshore storm bars. 

Next week (Mar 13th)

A couple of moderate frontal systems through the Southern Ocean this weekend are likely to kick up some minor south swell early/mid next week, but really, is anyone interested in the specifics? There are much more important matters at hand in the short term.

Let’s see how it’s all tracking on Wednesday. Until then, take care in the water as there’s likely to be a lot of energy moving around.