Sydney Hunter Illawarra Forecast by Steve Shearer (issued Mon June 30th)

Features of the Forecast (tl;dr)

• Long range E swell persists Tues, easing Wed- completely overridden by large local swells
• ECL or Tasman low now expected to form in trough late Mon
• Building E’ly swells Tues with strong to gale force SW-S winds developing 
• L-XL E’ly and S’ly swells Wed with SW-S gales continuing
• Potential large rebuild in SE swells later Thurs into Fri depending on evolution of complex low
• Easing swells and improving winds Fri PM
• Fun leftovers this weekendwith light winds
• Check back Wed, dynamic forecast so revisions likely!

Recap

Plenty of fun sized S-S/SE swell over the weekend with 2-3ft surf both days, a notch bigger on the Hunter. Winds were offshore both mornings with a’noon SE breezes Sat, light NE seabreezes Sun. A clean morning on hand today with some small E swell filling in and offering up inconsistent 3ft sets under offshore breezes which are expected to tend mod to fresh S’ly this a’noon. A dynamic week is ahead with a deepening trough expected to spawn an ECL late today or o/night into Tues.

Long range E swell making landfall, will be completely overwritten by large swells tomorrow

This week (Jun30- Jul 4)

The Tasman Sea is poised to explode into storminess with a pair of troughs now in action. A Coral Sea trough deepens into a small low and becomes continuous with a NSW coastal trough which deepens today and forms an ECL over the next 12-24hrs. By first light tomorrow morning and ECL or variant thereof will be positioned off the lower end of the MNC, likely due east of Seal Rocks. Areas to the north of this low will be receiving W’ly to W/SW’ly gales to severe gales (storm force gusts possible) with winds moderating north of Coffs Harbour  while to the south we’ll see a narrow band of S’ly to SW’ly gales establish southwards to Ulladulla.  Winds on the south-east to north-east flanks of the low will be gale force E to E/NE infeeds, extending out into the Tasman and Southern Coral Sea. 

In the short run, weather and winds escalate o/night and into tomorrow morning with just a brief window of slightly more settled conditions allowing for some long range E swell to be utilised. By late morning that swell will be overridden by a rambunctious mix of short range S swell and large E swell. Size in the 4-6ft ramen by lunch-time will be orders of magnitude bigger by close of play- up into the 6-8ft range with 10ft sets. Bigger surf is on the cards if there is any extra ramp up in windspeeds with proximity leading to quick increases in size. 

The low remains close to the coast into Wed morning , hovering off the Hunter under current modelling as a powerful system. If it behaves as expected we’re looking at gales to severe gales (possible storm force gusts) from the SW-S/SW along the coast. It will be wild and woolly. 

The E’ly infeed looks to be split by a secondary low centre which moves SE of the centre and then rotates around it in a Fujiwhara type affect.

This is a very dynamic system close to the coast so any small differences in actual outcomes as opposed to modelled outcomes will see significant changes in surf conditions . Wed remains very sizey with initial E swells levelling off, tending more E/SE and still blended with large local S swells from proximate gales. That’s likely to see a stormy blend of swells to 6-10ft, favouring big wave reefs with some wind protection.

Confidence is lower as we head into the back half of the week.  There is a modelled scenario where the secondary low slingshots around the primary low and aims up S-S/SE winds at NSW. That would see a major rebuild in size from that direction later Thurs into Fri morning before easing off. Potentially up into the  8-10ft range with bigger sets. As a minimum size remains elevated through Thurs and Fri with winds easing laster Thurs and further into Fri. 

Keep tabs on comments and updates in real time. 

This weekend (Jul 5-6)

Conditions will be settling right down into the weekend with the ECL expected to rotate out of the swell window later Fri into Sat and high pressure moving over over the inland and then off the NSW Coast on Sat.

That should bring settled weather, light winds trending N’ly on Sat with winds potentially swinging even more NW on Sun as a broad inland low approaches from the W. 

Clean leftovers to 3-4ft (occ. 5ft) on Sat, dropping through the day.

By Sun we’ll be mopping up with small leftover from the S-SE to 2ft. 

Next week (July 7 onwards)

Nothing much to get frothed on next week- although we will probably be stoked to have some clean-up weather. The broad low moves off the South Coast and tracks south, aiming swell generating winds at Tasmania that are likely positioned too far south to have much impact on the NSW Coast. That would see small surf and offshore winds for the first half of next week. 

Plenty to focus on short term with the upcoming ECL so check back Wed for the latest.