Sydney Hunter Illawarra Forecast by Steve Shearer (issued Mon April 29th)

Features of the Forecast (tl;dr)

• Fresh SW-S winds establishing tomorrow with some short range S swell building in the a’noon
• Slow moving high now brings SE winds through the working week and into the weekend
• Moderate S swells Wed
• Longer period S swells build in Fri PM, extending into Sat
• More long period S swell Sun PM into Mon
• Trough may develop Sun into Mon bringing SE-E/SE winds
• Surf potential next week depends on evolution of trough, possibly sizey SE-E/SE swells - check back Mon for latest revisions 

Recap

Cleanish and still some chunky S swell Sat with a range of sizes reported from 2-3ft to 4-5ft on the Hunter under light morning land breezes which tended SE then NE in the a’noon. Clean again Sun morning with some leftover 3ft sets, easing through the day with a mod NE seabreeze. Today is seeing some small leftovers in the 1-2ft range under morning NW winds, expected to tend pre-frontal N’ly and freshen through the day.

Few small beachies around for the early

This week (Apr 29-May3)

We’ve got another monster high S of WA (1039hPa), expected to move into the Bight and strengthen (1042hPa) with a trough and front expected to track north along the NSW coast from tonight and bring a robust SW-S change before the southwards positioned high holds a ridge along the entire NSW coast for most of the week with a S-SE flow. A trough of low pressure NE of the North Island is deepening today but moving southwards at a clip through the swell window with reduced swell potential compared to Fridays notes. A strong frontal progression will bring S’ly groundswell during the week. Later polar fronts in the far southern/central Tasman remain strong and although better aimed at Pacific targets we’ll still see some significant sideband S’ly energy from them.

Just a note about winds first. The monster high becomes very slow moving this week, as it inches through the Bight. Thus we can expect a constant S/SE flow through the working week, probably extending into the weekend. You’ll have to hunt more protected spots for a clean wave with brief SW breezes likely not enough to clean up open stretches and S facing beaches through the week. 

In the short run we’ll see mod/fresh SW winds tending S’ly as the trough works it’s way north. We’ll see short range S swell build through the a’noon, likely up into the 3-5ft range but ranging much smaller into protected spots away from the wind.

Not much to recommend Wed as S/SE winds persist at moderate paces. A brief winds of SW breezes north of the harbour will open up a few semi-protected spots with swell in the 3-4ft range. There will be some better quality longer period S swell in the mix from the parent front with all sources easing during the day. 

The ridge does relax a notch into Thurs and with a shallow troughy area inland we may see a more definite land breeze for the early. Not a great deal of surf to play with though. S/SE swell to 2 occ 3ft from the fetch of SE winds in the Tasman. SE winds will likely kick back up to moderate paces after lunch.

Rinse and repeat wind-wise for Friday.  Early SW breezes at the usual locations before mod S/SE-SE winds kick in. Small S/SE swell to start with a few 2 occ. 3ft sets. Through the a’noon we’ll see a long period pulse fill from a strong polar system passing through this week. Fri a’noon should see some significant 4ft sets, with a few bigger outliers on hand. Unfortunately winds will still be from the southern quadrant so it’ll make accessing the full swell energy a real challenge.

This weekend (May4-5)

Strong S’ly groundswell will be on tap for Sat morning, likely up a notch on Fri a’noon with some 4-5ft surf at S facing beaches and bigger outliers possibly at magnets. Expect an inconsistent, flukey swell though and with more S-SE winds as the high slowly edges towards Tasmania. Early morning should see a SW breeze and that is worth aiming for.

Easing swells on Sun AM with SE winds expected. Through the a’noon we may see a super long period pulse push through offering some inconsistent 3ft sets.  We mentioned a trough system potentially deepening in the Tasman on Fri and models have now pushed this back into the late weekend or early next week. That leads to low confidence in modelled outcomes.

Nonetheless there is a chance we may see a deepening trough off the MNC to Central Coast during Sun, with SE-E/SE winds freshening to the south of the trough line into the f/cast region. We’ll refine this outlook as we go through the week. 

Next week (May 6 onwards)

Uncertainty remains high into next week with outcomes resting on the potential trough forming off the coast.

EC suggests the trough will deepen and create a complex system with a broad infeed through the Tasman Sea.

Under this scenario we’ll see moderate/sizey SE-E/SE swell developing next week, as S’ly groundswell eases from Mon.

GFS suggests there trough will dissipate early next week with moderate SE swells and winds from the same direction, gradually tending NE as the high finally moves into the Tasman.

We’ll keep track of things and report back Wed.

Seeya then.