Sydney, Hunter and Illawarra Surf Forecast (issued Friday 6th March)

thermalben's picture
thermalben started the topic in Friday, 7 Mar 2014 at 7:48am

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

Best Days: No great days in the short term. Lots of great days from Thurs onwards! Read ahead...

Recap:  Monday's late arrival of southerly swell held through Tuesday before bottoming out on Wednesday and Thursday. A small pulse of SE swell has filled into southern NSW today offering clean sets thanks to an early light offshore wind.

This weekend (Mar 7-8) 

Nothing great expected this weekend. Today's small pulse of SE swell will fade into Saturday, leaving us with small residual energy across much of southern NSW. 

A small high in the southern Tasman Sea will strengthen over the weekend, forming a modest band of east winds in the central Tasman Sea but of no great strength in our swell window (however, it'll generate strong trades in the northern Tasman, perfectly aligned for SE Qld and Northern NSW). As such a slight lift in size is likely through Sunday but I'd be surprised if we see more than a couple of feet at exposed beaches.

As for local winds, a trough over eastern NSW will combine with the Tasman high to direct moderate NE winds about most regions. However local areas of early offshore winds are possible. So in general expect small waves all weekend with variable conditions.

Next week (Mar 10-14)

We've got quite a dynamic weather chart at the moment, with strong activity expected to dominate the Tropical South Pacific and Coral Sea for some time (this is long overdue as well!). However, all of this activity will initially be mainly focused into the SE Qld/Northern NSW region, with smaller surf expected across southern NSW. 

Let's break down the forecast into specific features:

1. Broad, stationary belt of trades. Thanks to the weekend's Tasman high, which is expected to move only slowly eastward throughout the forecast period, we're looking at the existing trade belt strengthening and remaining stationary right through the next week or so. We'll initially see only a small percentage of swell from this source between Monday and Wednesday (slowly building from 1-2ft at first, to 2ft to maybe 3ft by mid-week) however we are looking at a further intensification of these winds throughout the week that may lead to a bigger increase later next week.

2. Coral Sea cyclone. Won't generate any swell for southern NSW (hell, won't directly affect SE Qld either) but it's presence will assist in anchoring the trade flow across the region, of which we'll be an indirect beneficiary by way of the trade swell mentioned above.

3. Tropical South Pacific cyclone. Model guidance is suggesting we'll see a bigger, more prominent Tropical Cyclone form near the Vanuatu region later this weekend or early next week, before slowing tracking east (towards Fiji) then possibly south.

As this system will be somewhat embedded within the sustained, stationary monsoon trough, it has strong swell generating potential in a couple of areas - firstly, it'll restrengthen the existing trade flow (see my notes re: trades above and a possible increase in swell later next week). However because of the favourable synoptic setup, the cyclone itself has good swell generating possibilities for the Australian East Coast sometime later next weekend or early in the following week, depending on how it behaves.

At this stage the models are split between a slowly meandering journey through the tropics - which may not deliver us much swell - or an extra-tropical transition along a southward path from Fiji to New Zealand. 

Gut feeling right now is that we'll see the latter develop, however the large distance between the mainland will cap wave heights on the East Coast. That being said,  I'm expecting this system to be large, slow moving and very intense - so the large, long period swell generated by it should kick up some pretty serious wave heights. 

As such I'm going to go out on a limb and call a 5-6ft+ long range E/NE groundswell for southern NSW, arriving sometime around next Sunday (16th) or Monday (17th). I'll update my thoughts on this on Monday.

4. S'ly change and associated swell. The change is due late Wednesday so we'll see a subsequent increase in small short range S'ly swell Thursday. At this stage some models have a small low forming in the Tasman Sea that may boost wave heights a little, however other models have the low skirting quickly to the SE (with no swell generating capacity). And with a dominant, building E/NE swell in the water it's not worth getting too caught up with this system. Let's review on Monday.

Long term (Mar 15 onwards)

Well, I've already covered the period up Monday March 17th (as per the E/NE groundswell) and this swell event is more than likely to be the dominant feature for at least the first half of that week, and possibly the back half too.

After what's been a pretty ordinary summer of waves from this particular swell window, I'm confident that we're looking at an extended period of quality, sizeable E/NE swells in southern NSW for the next few weeks. More on this on Monday. 

scoopmaster's picture
scoopmaster's picture
scoopmaster commented Friday, 7 Mar 2014 at 12:10pm

As much as I like the sound of a 5-6' E/NE groundswell I currently can't see it happening from this system. Looking at the 7 day synoptic charts on weatherzone, the strongest fetch is located directly above NZ north island on tuesday night before sliding east of new zealand during wednesday - shadowing the southern NSW coast behind the north island and also dropping in size and becoming more inconsistent due to distance. After wednesday the swell producing systems closer to NSW are not looking to generate more than a couple of feet of short range junk.

My forecast based on current charts for sydney / south coast would be an inconsistent 3-4' from the ENE friday, dropping slowly saturday. There is significant potential for an upgrade but the strong fetch expected to develop between the south pacific cyclone and high pressure to the south will have to extend west of NZ, or at least remain anchored in position above NZ.

thermalben's picture
thermalben's picture
thermalben commented Friday, 7 Mar 2014 at 12:59pm

All good SM, that's what these forums are good for (with regards to the forecast notes) - for people to throw in their two cents before it happens. I'm stoked you've had a say beforehand, rather than jumping in after the swell event with a "I could have told ya that ages ago" kinda comment.

However, personally - I don't really like sitting on the fence. My long range forecasts (and even short range) have a lot of gut-feel in 'em, rather just describing what the models are doing and verbalising the graphs.

Sometimes this pays off, sometimes it doesn't - but it's a lot more fun than taking the middle road :)

donweather's picture
donweather's picture
donweather commented Friday, 7 Mar 2014 at 1:18pm

Latest EC is off TAP!!!! However based on my observations this year, the Access G model actually seems to be the one on the money most of the time, especially with respect to tropical developments. At present, Access G and GFS are more aligned compared with EC, so I'm leaning towards the next cyclone whisking away to the SE and under going extra-tropical transition. Question is how quickly she'll do this along with how quickly she'll move SEwards behind the swell shadow of the sheep shaggin isle!!!

But by god, I'd kill for EC to come to fruition!!!!

Notwithstanding the above, until the imminent Coral Sea cyclone forms and meanders just off the Qld coastline, my confidence in any of the models past 3-4 days is VERY LOW!!!!

thermalben's picture
thermalben's picture
thermalben commented Friday, 7 Mar 2014 at 1:39pm

Yeah Access has been pretty good lately. Fortunately it's got a great prog too!