South-east Queensland and Northern NSW Surf Forecast by Steve Shearer (issued Wed Dec 18th)

Features of the Forecast (tl;dr)

• Vigorous S’ly change Wed with a spike in S swell building across NENSW, late in the day possible for SEQLD
• Solid short range S swells Thurs, easing during the day with moderating S’ly winds
• Long range E swells filling in Thurs and offering an inconsistent pulsey signal through Fri/Sat
• S/SE swells building Fri a’noon with light winds
• Sizey S/SE swells Sat with light morning winds tending N/NE in the a’noon and freshening
• Easing swells Sun with light morning winds and N’lies freshening
• Building NE windswells Mon under fresh NE winds, biggest on MNC
• Small E swells likely Mon/Tues
• Increasing confidence we may see a surface low develop off NSW South Coast with increasing S swells Xmas Eve and Xmas Day, favouring NENSW for size

Recap

We saw some workable E swell yesterday, in the 2ft range, generally with light enough winds for an all day grovel. Small E swells again today with light winds before a brisk S’ly change works it ways north, reaching fresh to strong paces through the a’noon. A steep spike in S swell is expected through the a’noon in NENSW, building into SEQLD late in the day/evening as strong winds to low end gales penetrate into sub-tropical latitudes.

Small, clean E swells before the S'ly hit

This week (Dec 18-20)

We currently have a deepening trough of low pressure developing behind a front which is bringing fresh and gusty S’ly winds up the NSW coastline, extending into the sub-tropics through the day. This trough of low pressure deepens into a surface low in the Tasman and is expected to track in a northerly direction through the short term. The initial spike in short range S swell will be reinforced by better quality S/SE swells late this week into the weekend. Still some very juicy possibilities for Xmas week, particularly Xmas Day as model runs start to coalesce on the probable  outcome of a deep low in the Tasman which generates sizey S swells. Read on for details.

In the short run we’ll see sizey S swell stabilise into tomorrow morning with fresh/strong S’ly winds tending S/SE at moderate paces in NENSW, fresh/strong in SEQLD.  Size in the 5-6ft range at S facing beaches in NENSW, smaller 3-4ft in SEQLD with small peelers available on the Points. We’ll see an easing trend in play through the a’noon as the initial spike in short range S swell starts to fade out. We should start to see some long range E swell fill in through the a’noon with very inconsistent sets to 3ft showing- that will add some extra energy into the Points. 

Winds start to ease on Fri as pressure gradient relax across the region. A lighter S’ly morning flow should tend to mod SE breezes before clocking around light E/SE in the a’noon. We’ll see S swells to 3ft with better quality S/SE swells filling late in the day to 3-4ft with the occ. bigger set. Conditions won’t be perfect across exposed breaks but there should be plenty of workable options under a light onshore flow. A small signal of long range E swell continues to offer an occ. 3ft set in the mix as well.

This weekend (Dec21-22)

Sat still looks good under light morning land breezes tending to light E/NE-NE breezes through the day, getting up to mod/fresh N/NE during the a’noon in NENSW, lighter in SEQLD. Good quality mid period S/SE-SE swell in the 3-4ft range with occ. 5ft sets offers up plenty of opportunity across open beaches to reefs and points. Long range E swell throws up the odd 2-3ft set into the mix.

Easing swells into Sun with early NW breezes tending light, then moderate/fresh NE in the a’noon across NENSW as weak high pressure sits in the Northern Tasman and a trough lingers off the coast. SEQLD looks to have a much lighter NE flow so open beaches and backbeaches should stay cleaner longer. Fun sized SE swells to 2-3ft (occ. bigger set) early, ease back during the day. The last dregs of E swell will supply a very occ. 2ft set. 

Next week (Dec23 onwards)

Very complicated synoptic set-up as we move into the Xmas week. First, looking to the north a weak monsoonal low looks to form off the North QLD Coast and drift into the Coral Sea. Under present modelling the system remains weak and only generates small E’ly swells for the sub-tropics. We’ll monitor that in case of any further development. 

To the south, things look to escalate quickly during Mon as a low forms off the Gippsland Coast. We should see some NE windswell develop into Mon- focused on the MNC to North Coast- from winds feeding into the developing low. We’ll pencil in 3ft surf for Mon, under an initial NW flow before the low brings a S’ly change late in the day or just after dark. 

A rapid deepening of the low o/night Mon into Tues is now progged by major weather models as it moves slowly E-E/NE into the Tasman (see below). 

Under current modelling the resulting fetch of SW-S gales would generate a spike in new S swell Tues up into the 4-6ft range, smaller 2-3ft in SEQLD, under a mod SW-S flow tending S-S/SE during the day.

If the low behaves as currently modelled we’d expect a similar sized surf into Xmas Day in the 4-6ft range in NENSW, smaller 3ft in SEQLD,  under S’ly-SE’ly winds, easing during the day as the low slowly moves Eastwards.

Surf then slowly backs down through Boxing Day then eases more rapidly into the weekend with light winds expected tending N’ly and freshening.

Further ahead, more troughiness in the Tasman is expected into the New Years week. We may see another low pressure form, although models are in poor agreement. 

Still plenty of moving parts, particularly if the monsoonal low gets wound up.

Let’s see how that looks Fri, as well as another look at this potential Xmas Day swell. 

Seeya then.