Sydney Hunter Illawarra Forecast by Steve Shearer (issued Wed July 3rd)

Features of the Forecast (tl;dr)

• Average but surfable conditions for the rest of the week with plenty of chunky SE swell rebuilding from Wed PM
• Easing winds over the weekend with slowly easing SE swell, biggest Sat
• Long period flukey S swell showing Sat a’noon and into Sun 
• Long period S swell pulses Mon/Tues next week with favourable N-NE winds
• Increase in E/NE swell likely by Wed
• E/NE swell filtering down from sub-tropics at increasing levels from mid next week, extending into next weekend with winds looking good

Recap

Plenty of chunky S-S/SE swell in the 3-5ft range on hand through yesterday and today but winds have been tricky to negotiate with basic mod/fresh S-S/SE flow. The unstable air mass has led to some local wind circulations around squalls and storms which offered periods of calmer or even offshore winds yesterday but you had to be Johnny on the spot. Otherwise, yesterday saw the cleanest conditions early with a morning SW-S flow. Today is less benign with onshore S-S/SE winds up earlier and blowing out most spots. There are some smaller, cleaner waves around for the keen at sheltered spots but quality is mediocre.

Very ratty this morning under SE winds

This week (July 3-5)

The synoptic pattern remains dominated by a massive high pressure belt under the continent, currently with two large cells of 1036 and 1037 hPa below either edge of the continent. This eventually converges into one huge high (1042hPa) through there end of the week as it slowly moves towards Tasmania over the weekend and the Tasman Sea into next week. A low in the Tasman is moving north with a slingshot fetch of S-SE winds expected to rebuild wave heights from the S-SE later today and into tomorrow while a trough of low pressure in the Coral Sea is sending more E’ly angled swell into the sub-tropical Points. The combination of low and high pressure is maintain a firm ridge along the eastern seaboard with plenty of S-SE wind.  A very active July map.

In the short run and winds will remain mod/fresh SE with a brief window of cleaner conditions in the morning, more likely across the usual suspects north of the Harbour. S/SE swell from todays boost will continue into tomorrow in the 4-5ft range with some bigger sets with the slightly improved swell direction helping more protected locations see a little more size. 

Rinse and repeat for Fri. Similar mod S-SE winds with morning SW breezes across the region, more W-W/SW across the Northern Beaches. Size will be similar, but offset by the angle going a little more favourable SE. Expect raw, lumpy 4-5ft surf across open stretches with 3-4ft surf in more protected locations. 

This weekend (July 6-7)

We should see coastal pressure gradients start to ease over the weekend as high pressure drifts over Tasmania and the dominant S/SE-SE swells of this week will be on an easing trend as well.

Sat still looks a little iffy for winds with the S-SE flow hanging in there. Reasonable confidence we’ll see a morning land breeze but we may still see some residual lump and bump across open and especially S facing stretches of coast. Swells from the SE should hold in the 3-4 occ. 5ft range, easing through the day. The series of S’ly groundswell pulses we mentioned on Fri now look flukier and even less well aligned for the East Coast. Nonetheless we should see traces of long period S swell Sat, boosting a notch into the a’noon. Winds won’t be favourable but a few 3ft sets should be showing after lunch.

Sunday looks a better bet for winds, with morning offshores well entrenched into mid-late morning at least and light winds in the a’noon, possibly even tending NE south of Jervis Bay, more SE in the Sydney region. Surf will be generally small, with leftover SE swell to 2ft. S swell magnets should see some S groundswell to 2 occ. 3ft but it will be flukey and not showing everywhere.

Next week (July 8 onwards)

High pressure moves into the Tasman next week, setting up a broad E’ly flow, initially in the Coral Sea and then extending into the South pacific and Northern Tasman. There are some elements suggestive of a "trough block" with a stationary trough line in a N-S position in the Tasman and Coral Seas and winds feeding into it (see below)- we'll review that on Fri.

We should see light winds to start the week, tending variable/NE in the a’noon Mon and more true N-NE on Tues.

There should be a few fun beachies around with small E’ly swells starting to filter down in the 2ft range Mon, possibly a notch bigger Tues. A last pulse of S swell looks to show Mon a’noon and persist into Tues with 3ft sets at S facing beaches and reefs. Worth a hunt around with favourable winds.

By mid next week and certainly later next week we should see E-E/NE swells start to slowly boost as the fetch starts to thicken in the swell window and migrate into a more favourable position for temperate NSW. Wed onwards looks fun as winds shift more W’ly under the influence of an approaching inland trough and frontal system. We’ll see how it looks on Fri but it’s worth pencilling in Wed-Fri next week for fun sized 2-3ft surf  likely building to 3-4ft or bigger 3-5ft depending on how the fetch shapes up. There are reasons to have a more bullish outlook but let's see how it looks Fri.

Longer term and it looks likely that quality E/NE swell will extend into next weekend. A complex low system approaches from south of the continent during this time frame so we’ll see how that looks on Fri. Best case, we get a return serve from the S as it enters the southern swell window.

Check back Fri for the latest.

Seeya then.