South-east Queensland and Northern NSW Surf Forecast by Steve Shearer (issued Mon 19th May)

Features of the Forecast (tl;dr)

• Very complex outlook as low pressure trough deepens off MNC coast this week, potentially with multiple low centres within
• Building swells Tues, staying elevated Wed
• Likely SW-S winds for most of the region, possible W-W/SW near trough line or small low centres- keep tabs on local winds!
• Easing but still sizey Thurs with tricky winds- likely offshore for most of region
• Size and winds dependent on movement of trough/low- E swells stay sizey into Fri and the weekend but low confidence on specifics
• More E swell next week, this time longer range
• Potential for sizey S swells next week as front/low push into Tasman
• Very dynamic situation, stay tuned for updates and revisions!

Recap

Saturday offered up some small, fun E swell in the 3ft range with clean conditions under light winds.  Smaller swells from the E on Sun but a strong signal of S swell pushed across NENSW in the a’noon with sets topping out at 4ft+ at S exposed breaks, under mod SW-S winds. That swell has eased back across NENSW, still showing some 2-3ft size across SEQLD S facing beaches with a new signal of S swell now building across NENSW as a trough deepens off the Mid North Coast. Mod/fresh S’ly winds are developing across most of the region, although there are pockets of more W/SW-SW wind around the trough line between Yamba and Coffs.

Another flood plume out of the Tweed with bluewater and fun S swells in close

This week (May 19-23)

A very unstable, dynamic synoptic chart this week with a large high (1034hPa) moving from the Bight through Victoria, with a coastal trough deepening on the leading edge of the high directing very moist onshore winds across Central NSW, extending up into the sub-tropics. We still have some model uncertainty over the fate of this trough. Fridays forecast of a low or ECL variant was downgraded into a persistent trough over the weekend but there are still model runs suggesting a low or (more likely) multiple embedded lows will form in the trough line this week. These small lows may move north, then east and finally south or may coalesce in a more classic Tasman Low or ECL variant. With so much uncertainty still around be prepared for major revisions as we move through the week. This is a nightmare to forecast!

In the short run the trough is likely to deepen and angle NE-SW with a position around Coffs. Areas around or north of the trough line see W-SW winds, SE to the south of the line. Further north a more general SW-S’ly flow is expected. Keep tabs on local winds if you can- with so much instability around we may see wind reversals around small, local circulations. Building swells are expected with size expected to trend upwards from 4ft into the 5-6ft range, likely bigger on the MNC and grading smaller the further north you go into QLD. Expect big intra-regional differences in surf size and quality!

Plenty of size Wed, thats about the only thing we can have confidence in. E/SE’ly swells to 5-6ft with bigger sets on the North Coast to MNC are on the menu. As far as local winds go- confidence is extremely low. EC is the only model suggesting the trough or low remains off the MNC with similar winds to Tues. GFS and ACCESS move the trough/low northwards (potentially pushing a small low centre onshore) which would bring widespread onshore SE-E winds across NENSW up to the Gold Coast, with a SW-S flow on the Sunshine Coast. Keep tabs on local winds and below the line commentary as we update in real time. Lots of potential outcomes are on the table, including really good, offshore surf. 

Forecast confidence remains low as we move into Thursday. Lots of outcomes still on the table.  The trough off the MNC-North Coast may deepen into a low and track southwards as suggested by EC and ACCESS. Or the whole pattern may just wash out  into a generalised onshore flow with easing swells (GFS resolution). We’ll still see plenty of size though with E’ly swells at least 4-6ft, bigger on the MNC. Stay tuned and we’ll try and update below the line before Wed’s notes. 

Similar low confidence for Fri as model divergence widens over the fate of the trough/low in the Tasman. European model and ACCESS favour the low to move southwards with offshore winds through Fri. GFS is less bullish with easing but still onshore winds and smaller swells from the E.

This weekend (May24-25)

Same very low confidence applies to the  weekend f/cast, so take current wave model output with a grain of salt. About the only thing we can be sure of is swell will be from the E through E/NE. Either solid from a low moving southwards through the Tasman or more modest from an E’ly fetch off the top of the high. For the sake of it, we’ll pencil in 3-5ft and adjust up or down as we get more clarity though the week. 

Winds are likely to tend N’ly through NW’ly over the weekend as a major low-pressure approaches from the west. 

Next week (May 26 onwards)

A broad E’ly fetch developing through the South Pacific will provide more E’ly swell into next week with improving quality as wavelength draws out.

That’s likely to be overshadowed in NENSW by strong S swells as a front and parent low moves aggressively into the Tasman early next week (see below). 

Too early to have confidence in size or timing but early indications are looking like it will be significant S swell event, likely developing late Tues/Wed. 

Lot’s of short em uncertainty to get through before then so check back Wed and keep tabs on below the line comments as we track this dynamic Tasman Sea weather event. 

Seeya Wed!