South-east Queensland and Northern NSW Surf Forecast by Steve Shearer (issued Fri Sep17)

SE Qld Forecast Summary (tl;dr)

• Better angled SE swell Fri PM, easing slowly through Sat with a small window of favourable winds before strong N'lies kick up
• Lighter N'ly winds Sun with leftover SE swell favouring exposed beaches
• Potential strong S swell Wed/Thurs, biggest in NENSW, as deep Tasman low forms

Northern NSW Forecast Summary (tl;dr)

• Better angled SE swell Fri, easing into Sat with a small window of favourable winds before strong N'lies kick up
• Flukey winds Sun, shallow SE change expected in NENSW, with some fun leftover SE/ESE swell
• Potential strong S swell Wed/Thurs, biggest in NENSW, as deep Tasman low forms
•  S pulses likely into next weekend, stay tuned for details

Recap

Yesterday came in at the top end of f/cast expectations, with greater amount of ESE swell in the mix, along with dominant SSE swell. Size was in the 3-5ft range across NENSW, though the 5ft sets were few and far between. SEQLD saw 2-3ft surf with some nice peelers getting into the more protected locations courtesy of the E’ly component of the swell. Fresh S’ly winds kept surfing confined to more protected locations. Energy has dropped back a notch today, although there were still some inconsistent 4ft+ sets in NENSW, grading smaller 2-3ft in SEQLD. Conditions were clean early with a morning offshore breeze, before winds tended E/SE, clocking around to the E/NE as the a’noon wore on. Another fun few days of waves to add to the great run we’ve had. 

This weekend (Sep 18-19)

We’re now on the tail end of the swell from the Tasman low, with a last little fun sting in the end of the tail expected this weekend and some tricky (largely unfavourable) wind shifts expected. Read on for details.

Elongated high pressure now covers the Tasman sea adjacent to the East Coast, with a pressure gradient squeeze expected to intensify over the next 24 hrs as a trough and front approaches from the west. That will see N’ly winds freshen through Sat, with only a brief period of more favourable WNW to NW winds on offer early in the morning. There’ll be swell in the water from the ESE, mid period swell generated by a flare up of the low later Thursday. This is expected to be in the 3-4ft range, with an easing trend through the day.  By close of play N’ly winds are expected to reach 20/30 knots in NENSW, a little lighter in SEQLD but you’ll need to find shelter at a backbeach to get anything surfable.

Sunday see plenty of action as far as wind changes go. Winds are likely to tend light NW through N early and it’s likely there’ll be plenty of leftover N’ly scarring. A weak trough then brings SE winds along the coast, with the wind change sputtering out somewhere around the QLD border. Expect light NE winds north of the change, and these NE winds will re-establish through NENSW later in the a’noon. A last little pulse of well angled ESE swell from the Cook Strait fetch today provides some mid-period surf in a fun sized package with some inconsistent 3ft sets. This swell is likely to back down quickly through the day so get into mop up mode early Sunday. 

One last swell source is possible Sun, with a fetch of W’ly winds exiting Bass Strait Sat PM. At present models show windspeeds maxing at strong wind/low end gale level- which is at the bottom end required for a Bass Strait fetch to produce anything meaningful due to the refraction back to the coast from such an off-axis fetch. 

Despite that flukey nature of the source fetch, it may produce a few stray 2-3ft sets, at S swell magnets in NENSW through late Sunday a’noon.

Next week (Sep 20) and beyond

Another very dynamic week ahead and with major model divergence between the main weather models it’s likely we’ll be back in here with revisions on Mon.

We’ve got a series of fronts and deep Tasman lows passing through, with an unstable troughy pattern in the Tasman sea. This pattern is being anchored by a large high which is expected to become slow moving in the Bight early next week and maintain tight pressure gradients with fronts and a possible low in the Tasman.

Monday will be the low point of next week, so we can book that in for a lay day. Pre-frontal winds maintain a fresh NW to N’ly flow through the day,  A few stray 2 ft sets  in the morning will drop right back to tiny surf during the a’noon. 

Tuesday is where life gets very interesting for the Tasman sea. The crux of the matter is a major front pushing NE up into the Tasman, an upper cold pool moving across the interior , both interacting with a lingering trough line. 

GFS (and other) models develop a low in the increased vorticity between the advancing front and lingering trough, likely off the Hunter Coast. Under this scenario, severe gale to storm force winds rapidly develop just off the coast in a broad fetch extending from north of the Hunter to the far south coast. Surf is likely to stay tiny/flat across the region Tues as offshore winds wind up and iron out any leftovers.

Under current modelling we'd expect to  see a rapid, step-ladder increase in S swell, likely early Wed morning across the Mid North Coast, mid morning through Yamba, and reaching the QLD border by lunch-time. We’d expect strong to gale force SW to S’ly winds accompanying the building swell. Under this scenario we’d be looking at surf building into the 6-8ft range during Wed at S facing beaches in NENSW, grading smaller 3-4ft in SEQLD. Surfing will likely be confined to sheltered spots and regional Points where size will be determined by exposure to the full brunt of the S’ly swell. 

Keep in mind under the EC scenario we are looking at a much more modest swell event. A mix of S swell trains building through Wednesday, likely into the  6ft range with fresh S’ly winds and a much steeper roll off in size through Thursday. 

A broad easing trend is likely under both scenarios through the end of next week, with winds likely to ease and tend offshore. 

Thursday and Friday offer potentially good to excellent surf across regional Points in NENSW with slow easing surf in the 6ft+ range, with smaller but fun surf in SEQLD in the 3-4ft range. We'll come back and finesse those sizes on Monday.

Into next weekend and further strong low pressure systems under Australia are expected to generate more S swell for the region, potentially long period and quite sizey. With so much instability and short term dynamism on the charts we’ll flag next weekend for at least moderate S swells with most major models showing S’ly component winds in the central and lower coast of NSW as fronts push northwards along the coast.

Don’t put the step-ups and guns away just yet. Have a great weekend and check back Mon for a fresh analysis of next weeks developments.