Tons of action ahead as Easterly Trough low forms off Sydney tomorrow
Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri 1st July)
Forecast Summary (tl;dr)
- Range of wind conditions over the weekend depending on exact position of developing low
- Most likely best from Central Coast to Hunter, onshore from Sydney south
- Small S swell groundswell Sat, easing Sun
- Short range E-E/SE swell Sat, becoming large and stormy Sun PM
- Large E/SE swell Mon with onshore winds for most of the region (possible variable/offshore on the Hunter, depending on trough)
- Easing E/SE swell Tues, with rebuild in large S/SE swell and strong S/SE winds
- Plenty of SE winds and swell Wed, slowly easing Thurs/Fri
- Strong E/SE groundswell likely next weekend with good winds
- Potential for more strong swell following week, stay tuned for updates
No great surf to speak of since the last f/cast. Yesterday saw a declining signal of SSE swell, topping out around 2-3ft own the Hunter, smaller 2ft elsewhere and clean early before SSE winds kicked in. Today is similar with a small, sloppy signal of S to SSE swell in the 2ft range and S’ly winds now kicking in as we enter into a dynamic coastal weather event.
This weekend (July 2-3)
OK, here we go. We are starting to get some model agreement on a developing easterly trough low expected to form off the Sydney/Hunter coast through tomorrow. There’s still a degree of uncertainty as to the exact position of the low axis, which will make wind f/casts a bit rubbery and really, coming down to a game of kilometres.
Let’s look at what we know. The South Coast to Illawarra and South-side Sydney looks the most likely to be in the direct onshore flow of the developing low, so expect a write-off for the weekend for these areas with onshores and rain and building short-range E’ly swells becoming very large through Sun a’noon.
Sydney north of the Harbour is the most in doubt, with a possible light and variable flow if the low axis is slightly south of Sydney (GFS scenario). Central Coast and Hunter are far more likely to have a variable, lighter offshore flow through Sat. That may extend into Sun morning (likely) before all hell breaks loose and E’ly to SE’ly strong winds to gales extend through the entire region as the low winds up and deepens.
Surf-wise there will be some longer period S’ly groundswell in the mix from a passing frontal system Thurs/Fri which will add around 3-4ft of surf to S facing beaches on the Central and Hunter coasts on Sat, easing into Sun.
Further south building short range SE-ESE surf will whip surf up into the 4f range by close of play.
Sunday sees the proximate fetch to the NSW Central and Southern Coast really increase in strength (see below). Winds increase to gale force, possibly strong gales and with proximity equaling a rapid increase in size we can expect surf through Sun, especially after lunch to become very large and stormy. Size up in the 6-10ft range is expected, with rideable locations limited to a handful of novelty spots.
Next week (July 4 onwards)
We’ll still be playing a game of Kilometres on Mon morning. The low axis is expected to be off Sydney with a trough line linked to the low hovering around the Hunter Coastline. Areas on the trough line or north will see a variable flow, becoming more offshore (W’ly) the further north you get from the trough line. That trough line may still meander further south during the day, extending variable winds into the fringes of the Sydney basin, or it may retreat inland, with winds freshening from the Southern quarter.
Most of the f/cast region is going to be under the influence of a stiff, SE-SSE flow and surf is expected to be solid and stormy. Likely in the 8ft range early, but easing a notch or two during the day as the fetch rotates more SE through S. That will open up some protected locations during Mon.
The low moves away through Mon, although a secondary centre may linger about the Central Coast region- stay tuned for updates over the weekend. As it does, it aims up a more SE angled fetch at the region which then tracks in a NNE direction through the day. This should see a renewal in more SE-SSE angled swell through Tues. Plenty of wind from the same direction through the day, keep expectations pegged. Size should rebuild from 3-5ft during the morning up into the 8ft range, bigger on the Hunter and more exposed S to SE facing stretches. Expect smaller surf at more protected locations, which will be the only places surfable under 20-30knot winds from the SSE.
By Wednesday it looks like a classic La Niña map. Strong high just SE of Tasmania with a low in the Central Tasman directing a huge windfield through most of the Central to Northern Tasman Sea. Expect plenty of SE winds and swell, likely in the 6-8ft range, easing a notch during the day.
Further into next week, and allowing for the fact the dynamism leads to low confidence this far out and it looks like the low in the Tasman moves northwards and connects with the remnants of the trough line in Coral Sea. That reinvigorates the low near the North Island, with a fetch of gales then activating off the west coast and back into the Tasman, with the low doing a slow loop de loop back south through the Tasman.
If that model scenario plays out (both GFS and EC suggest some version of it) then we will be looking at more strong swell from the E/SE to SE as the low tracks down the West Coast of New Zealand (see below).
So expect an easing trend through Thurs/Fri, although still with plenty of size and winds from the SE-S.
Strong new E/SE swell is then probable by next weekend 9/10 July and beyond.
Stay tuned to the comments over the weekend as the event unfolds and we can update using real-time Obs and check back Mon for a fresh and full update.
Have a great weekend!