Tropical cyclone expected to bring strong E swells for most of the coast
Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 6th Feb)
Forecast Summary (tl;dr)
- Light onshore E-NE pattern extends through most of this week, lightest winds in the AM
- Easing surf Tues
- Small S swell Wed PM, holding into Thurs
- Small portions of E/NE swell showing later Thurs, holding into Fri
- Potential longer period NE cyclone swell later Fri, more likely Sat
- Increase in E/NE cyclone swell later Sat (still small)
- Much larger E/NE-E swell Sun, holding Mon, slowly easing next week as Ex TC slowly drifts towards North Island
- Stay tuned for updates on this dynamic swell event
Nice mixed bag over the weekend with Sat seeing mostly E swell, clean under offshore winds. Size was in the 2-3ft range for most of the day wit a late pulse seeing more consistent 3ft surf. Sunday eased in size from the E with early light offshore winds tending S through E/SE as the day worn on. A pulse of S swell worked it’s way up the coast, mostly apparent in the a’noon with a few S swell magnets in the 4ft+ range, mostly 3ft at S facing beaches. Today is seeing more S swell in the 3ft range at S facing beaches, bigger 3-4ft on the Hunter. Early light winds have quickly tended to onshore breezes with surface conditions rapidly becoming ordinary. Looks like we have some juicy tropical developments on hand this week, with a chunky swell expected from a southwards tracking cyclone. Read on for details.
This week (Feb6-10)
We’ve got a return to a typical Summer synoptic pattern after a large, mid-latitude low cleared Tasmania on the weekend and quickly exited across the Tasman Sea. Weak high pressure has now moved into the lower Tasman, with light/mod onshore flow across the Eastern Seaboard- NE in temperate NSW, tending more SE in the sub-tropics. A convective cloud mass between the Solomon Islands and Vanuatu is expected to consolidate and deepen into a tropical cyclone by mid week, tracking back into the Coral Sea towards the tropical QLD coast before recurving and drifting Southwards through the Coral Sea and eventually towards the North Island. Swell from this system is expected across most of the Eastern Seaboard.
In the short run and both swell sources from the E and S dry up overnight and through tomorrow, leaving a small mixed bag topping out around 2ft at open beaches. Light onshore E’ly winds will tend E/NE to NE through the a’noon so you’ll need your grovel head on to get a surf in.
A front briefly tracks NE into the lower Tasman today and tomorrow sending a pulse of refracted S swell up the NSW Coast (see below). Wind speeds are decent enough and the entire fetch is long so swell periods in the 13-14 second band are expected. An undersize start is on the books for tomorrow with S swell filling in across the Sydney Basin mid-late morning in the 3ft range at S facing beaches, slightly bigger on the Hunter. Mod E to NE winds continue so you’ll need to hunt around for clean conditions.
No change to winds on Thurs, more mod E to NE winds, likely straight E/NE at most spots. S swell should hold into the morning at similar sizes- 3ft or so at S facing beaches- before easing during the day. All eyes will be to the North where a tropical cyclone is likely to be dominating the charts. A precursor tradewind fetch through the Southern Coral and Northern Tasman seas will see small amounts of short period E/NE swell start to filter down to temperate NSW. No great size is expected, just a weak 2ft or so of summer slop.
More of the same winds to round off the working week- straight E/NE, possibly tending to NE sea breezes. We may see light land breezes develop but any W’ly component wind is likely to be light and brief. A weaker following front to Mon/Tues’s affair supplies a small S swell signal Fri-likely 2ft or less at S swell magnets. We may see a rare NE-NNE swell start to filter down from the tropics as potential TC Gabrielle develops gales to severe gales across the NE quadrant as it drifts back into towards the QLD coast. These swells, when they occur are usually very flukey but models are in reasonable agreement on the fetch and the track. We’ll flag for now some potential 2ft sets winding down the beach Fri a’noon, although Sat looks a safer bet.
This weekend (Feb 11-12)
The TC is likely to tracking slowly SE by this weekend, just on the inside track of Norfolk Island, and likely to be undergoing extra-tropical transition as it does so. Local pressure gradients are likely to be weak, with light breezes expected Sat, and a possible S change Sun as a trough moves north along the south Coast.
We’ll finesse size and timing as we move through the week but Sat is likely to remain quite small, with rare long period NE swell offering up 2-3ft sets. Through the a’noon a bigger payload of E/NE swell, generated as the TC moves more properly into the temperate NSW swell window, makes landfall. That's likely to push size up into the 3-4ft range during the a’noon.
A step change in size is expected Sun under current modelling as stronger E swell fills in. Size in the solid 6ft range is a fair ballpark to start with- with plenty of upside if the system stalls as it undergoes transition. Light N’ly winds tend NE, with a potential S-SE change for the late.
Next week (Feb 13 onwards)
Strong E swell maintains plenty of size into Mon, with a conservative expectation of solid 6ft sets. S to SE winds are on the menu as the trough stalls on the Mid North Coast.
A slow easing trend is then likely through Tues/Wed as the system( likely a serious extra-tropical storm smashing the North island) becomes slow moving with the fetch truncated by the North Island.
Pencil in plenty of E swell through Tues/Wed with light winds likely in weak, troughy synoptic pattern.
Further ahead and looks frontal activity into the Tasman by mid next week, suggesting the next swell cycle will be another small series of S pulses.
Confidence is low this far out and we have a potential cyclone to deal with before then.
Check back Wed and we’ll start to dial in size and timing of upcoming cyclone swells.