Analysis: Cold water and green seas

Craig Brokensha
Swellnet Analysis

Regular Swellnet readers would be familiar with the yearly article explaining the phenomena behind the cold water upwelling that's most noticeable during East Coast summers.

It's a fairly simple process where persistent strong north-east winds transport the surface ocean water away from the coast. Though the wind blows towards the coast, the surface water counter-intuitively moves offshore due to the Coriolis Effect, or the spinning of the Earth on its axis.

As the warm surface water moves offshore it's replaced by deeper colder water in a process called coastal upwelling.

The phenomena is pronounced as it usually happens during bouts of hot weather weather when surfers get more than they bargained for. Keen for a refreshing session they're forced to freeze in boardies.

This cold water is usually upwelled from the continental shelf, but if the process continues for a sustained period we get even deeper colder water brought up from beyond the shelf break. When looking at Google Maps or any other map showing details of the ocean floor (bathymetry) you can identify areas where the shelf break comes close to the coast.

It's these areas that see the most pronounced upwelling events and concurrently the biggest drop in temperature.

Along the East Coast you can identify these regions as close to Jervis Bay, Narooma, Seal Rocks followed by the upper Mid North Coast and Ballina.

Upwelling is a major source of primary production, as the nutrient rich water is bought into the photic zone - where the sunlight impacts the water column - causing photosynthesis and the blooming of phytoplankton.

Phytoplankton are the base of the food chain and everything builds up from here.

Chlorophyll is needed for the photosynthesis process to take place and this is what we observe when the water starts turning that greeny colour.

The more concentrated the phytoplankton the more intense the colour but also the lower the visibility. This is why if you're a diver or spear fisherman you'd be best to avoid swimming after days of strong north-east winds on the East Coast as the visibility will likely be compromised. You may also notice in some areas the upwelling also causes corn-flake like red/brown floaties in the water.

The amazing thing is that the chlorophyll can be observed by satellite and if we look at the latest available data for the East Coast (18th December), where we've had nearly a fortnight of non-stop and at times strong north-east winds, we can see a few hot spots.

The main one is off Seal Rocks and this is one of the most productive zones for upwelling off the East Coast. Being close to the shelf break and having the coast bend away to the south-west lends the area to rapid and prolonged upwelling events.

The other is just south of Ballina from Evans Head to Yamba with the East Australian Current sitting further offshore.

Currently the sea surface temperatures (SST's) off the Mid North Coast are well below what's sitting just offshore in the East Australian Current. Steamers are a must with 18 deg water, while it's 24-25 degrees only 20-30km offshore.

For this warm water to move back in shore we need a strong southerly change and unfortunately this doesn't look to occur within the next fortnight at least across the northern NSW coast, with a brief burst of southerly winds Sunday across the southern NSW coast, bringing SST's up a touch temporarily.

Therefore we're set for a continued period of cold greeny water.

On the upside, at least the fish should be on the bite.

Comments

freeride76's picture
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freeride76 commented Thursday, 3 Jan 2019 at 4:07pm

Unfortunately, while theoretically that cold green water might be nutrient rich, it completely shuts down the summer pelagic fish bite.

and all the inshore summer species like whiting, flathead, etc etc.

That cold green water is a fishos nightmare.

Craig's picture
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Craig commented Thursday, 3 Jan 2019 at 4:10pm

Ah yes I remember you mentioning this last time. Are they sitting on the edge of this boundary then you think? Offshore where it meets the warmer clear EAC?

tubeshooter's picture
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tubeshooter commented Thursday, 3 Jan 2019 at 8:36pm

Check the thermocline levels and go from there. Pelagics are still around .

jez's picture
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jez commented Thursday, 3 Jan 2019 at 4:57pm

thanks Craig,
Great article.
As a spearo, i am very interested to know where i might find that satellite chlorophyll map online?

Jezdawg

Craig's picture
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Craig commented Thursday, 3 Jan 2019 at 7:35pm

Here ya go Jez, click the Ocean Colour chart.. http://oceancurrent.imos.org.au/index.php

jez's picture
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jez commented Friday, 4 Jan 2019 at 7:10pm

Thanks Craig, much appreciated!

Jezdawg

donweather's picture
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donweather commented Thursday, 3 Jan 2019 at 5:37pm

When on gods earth are we going to see any wind with the letter "S" in it!!!

martymcnab's picture
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martymcnab commented Friday, 4 Jan 2019 at 4:46pm

Hey DonWeather, it's been happening for the last two weeks - "Sh*t" winds.

Gee I hate summer. Bad surf, hot humid weather. Roll on autumn!

Marty

Roystein's picture
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Roystein commented Thursday, 3 Jan 2019 at 6:39pm

i think you will find that chlorophyll is vital for photosynthesis to occur but is not produced during the process, but as you correctly mentioned the conditions cause an increase in phytoplankton concentration in coastal waters

Craig's picture
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Craig commented Thursday, 3 Jan 2019 at 7:42pm

Ah yes corrected.

The phytoplankton have chlorophyll which is used for photosynthesis. And when the nutrients are brought up from the deep the phytoplankton feed on them and increase in concentration, hence being visible from satellite.

blindboy's picture
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blindboy commented Thursday, 3 Jan 2019 at 8:37pm

Better green water than red tides.

nextswell's picture
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nextswell commented Thursday, 3 Jan 2019 at 10:24pm

Love these articles. Just north of coffs, hasn’t been a southerly wind for well over 2 weeks.

Casp's picture
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Casp commented Thursday, 3 Jan 2019 at 10:38pm

Hi Craig cheers for the article, I was thinking, “why the green water” in the surf this afternoon... during this surf the water had a very fishy smell about it! (like a can of sardines) is this a coincidence or would it have some sort of correlation with the Phytoplankton phenomena?

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 7:38am

Yeah that'd be a part of it for sure, had a similar solo green water surf on the lower MNC at the end of last year, was a bit on edge and could see the baitballs at times. Feet up!

Groper's picture
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Groper commented Thursday, 3 Jan 2019 at 10:41pm

Yamba surf report photo depicts it perfectly.
Start of a Fishers dream. First will come the Manta carrying Cobes!!!
We also get upwellings caused by strong currents pouring downhill past Byron that drag the inshore surface waters out.

freeride76's picture
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freeride76 commented Friday, 4 Jan 2019 at 7:35am

the downhill current is almost always warm blue water from the EAC.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 7:36am

I think he's referring to at the interface?

Groper's picture
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Groper commented Saturday, 5 Jan 2019 at 7:27am

Shape of the Coastline. The EAC pours past easterly point of Byron and doesn't bend back to the coast until around Coffs. As it flows down it drags the inshore waters around the Clarence Coast out which are replaced by upwelled water. Can often result in a mixture and clear green water.

lomah's picture
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lomah commented Friday, 4 Jan 2019 at 12:12am

Spent 3 hours in the water today on nsw south coast in boardies. Much warmer than Sydney Newcastle and mid north coast last week.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 7:37am

Great example and feedback. Thanks.

chook's picture
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chook commented Friday, 4 Jan 2019 at 11:59am

...if you do get any upwelling down that way, it is savagely cold. the continental shelf is very close to land along the narooma/bermagui/mimosa rocks stretch. (that's why it's a good place for catching marlin). coldest surf i've ever had is a summer surf at bermagui.

Lalic's picture
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Lalic commented Friday, 4 Jan 2019 at 7:46am

Surfed palms area last week and it was freezing (I reckon an honest 16 degrees two days) and in town the beaches were about 20. That often happens up there. Why is palms colder than Forster itself?

Now I'm down south coast just south of gerringong, and it's boardies and at least 20 degree water maybe a touch more.

Ps both coasts the water was as clear as I've ever seen it and totally pristine. No green?

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 7:51am

Interesting, maybe fresh upwelled water that's yet to really bloom? I have had murky green water at Palms many times before, but usually it's super clear.

cd's picture
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cd commented Friday, 4 Jan 2019 at 6:44pm

Most likely an influence from Wallis Lake. The cold water hasn't yet pushed into the system. Well was still warm where I was fishing last week.
Water dark in colour now at the Palms.

tidak_bagus's picture
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tidak_bagus commented Friday, 4 Jan 2019 at 7:21pm

My understanding is that cape Hawke interrupts the process and you won’t get upwelling north of the cape but south of the cape is cold. Yeah Boxing Day was warm but the day after was definitely down 16-17 degrees. Interestingly north of the cape today was warm but very green

thermalben's picture
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thermalben commented Friday, 4 Jan 2019 at 7:45am

Little patches of upwelling on the Tweed yesterday. Was super shallow too - duckdiving under a wave would bring an instant warmth, and then a brief colder flush as you came back through the surface layer.

P'tai's picture
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P'tai commented Friday, 4 Jan 2019 at 7:49am

Just been for a swim this morning at Forster, the water is cooler and has a green tinge to it, looks quite murky. Still nothing ridable tho.

Spuddups's picture
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Spuddups commented Friday, 4 Jan 2019 at 7:54am

I was up in Northern NSW in July and the water was nice and warm. The nights and mornings were rather cold (6 deg) with S-SW winds predominating till lunchtime every day. I was wondering if this situation is the opposite of the NE wind/ cold upwelling thing, meaning that the water from the warm E.A. current is being dragged onshore by the southerly.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 7:57am

Yep. Southerly winds push the displaced warmer water back into the coast.

That's why when we get a strong southerly change persisting for 24 hours or more it should start bringing the warm water back in.

Also coastal eddys can enhance (when flowing with the north-east wind) or prohibit upwelling in some instances.

donweather's picture
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donweather commented Friday, 4 Jan 2019 at 4:16pm

And this is one reason why i want winds with the letter "S" in them to return sooner rather than later. This by far is one of the most sustained cold water spells I can recall at this time of year for a long time.

groovie's picture
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groovie commented Friday, 4 Jan 2019 at 8:00am

The same high pressure system has sat in the Tasman now for well over 2 weeks, producing varying degrees of nor/nor/Easters & junky wind swell with a period of less than 7 sec. this pattern produces the Ekman effect which delivers our upwelling. It really is an early summer pattern that we haven't seen for the last few years on the east coast. Hopefully we also see strong lows develop in the Coral sea that drop into our swell window to produce some long period north swells with south winds, as we used to see in previous years after an extended period of no decent waves.

blindboy's picture
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blindboy commented Friday, 4 Jan 2019 at 9:31am

First week of Feb is always a good bet for a decent swell.

Spuddups's picture
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Spuddups commented Friday, 4 Jan 2019 at 8:03am

It's a fascinating subject. It has always intrigued be how Lima Peru is so close to the equator but has such cold water.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 8:06am

Those who frequent the South East coast of South Australia would be familiar with wearing 4/3 streamers in the peak of summer while outside the north-east offshore is blowing 40+ degree heat in.

The upwelling off that region is very cold under strong persistent summer south-easters.

thermalben's picture
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thermalben commented Friday, 4 Jan 2019 at 8:20am

Was chatting to a mate about that yesterday, who's heading west in Autumn, and asked what wettie he should take.

I said "I don't think I've ever gone to the west coast and thought jeez, I wish I had only brought a vest or a springy!"

Even if it is a little warmer, you'll probably benefit from the extra sun protection anyway. So the steamer always gets packed, even if it's in the middle of summer.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 8:25am

Yorkes was beautiful over Christmas, probably 20deg and fine in a 2mm short-arm springy. The gulfs do warm up a lot in summer though. Port Lincoln/Coffin Bay also experiences upwelling under those same south-easterlies in summer.

thermalben's picture
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thermalben commented Friday, 4 Jan 2019 at 8:45am

Yeah Yorkes has the benefit of both gulfs, the northern end of which can get very warm (and saline! As you know from your Honours thesis).. but crikey I have had some cold surfs over west in summer, mainly because the upwelling tends to occur in the lee of particular (small) geographical peninsulas, that also offer good waves on their eastern side under the prevailing sou'easters.

Tuna spotters reckon that's where they see some big biteys too.

freeride76's picture
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freeride76 commented Friday, 4 Jan 2019 at 10:03am

We've been pretty lucky here so far, a strong EAC and eddy around Byron has kept water temps nice.

it's amazing what effect the EAC and water temps have on local wind strengths and how they can mediate synoptic wind strengths, and conversely how easily strong feedback loops from Ekman transport and subsequent cold upwellings can create increased gradient wind Nor-easters.
When that pattern locks in it can really take a fair bit to dislodge.

The other day was a classic.
Synoptic nor-east wind was blowing all night and dawn had 15-20knot nor-easters at Cape Byron.
By mid-morning, with warm water and roughly equal land/water temps the arse dropped out of the nor-easter and we got something that happens quite frequently in these types of conditions: a mid-morning "glass off".
Glass off is used loosely but conditions definitely improve.

I think Hat Head is closest to shelf on east coast Oz and that stretch from Grassy Head to Point Plomer has the most extreme cold water upwellings in my experience.
Literally seen it go from 24 to 18 overnight under strong nor-easters.

On the other hand if anyone ever wants to see the strength of the EAC in summer go up to Smokey Cape light house and look roughly due east to Fish Rock.
When the EAC is flowing it's like a buoy sitting in a really strong tidal flow.

Paddledamnit's picture
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Paddledamnit commented Sunday, 6 Jan 2019 at 11:49am

Freeride, try spearfishing Fish Rock then in those conditions. My most memorable time was drift diving the rock while the EAC was in full force, and around 200m south of the rock I tried to reach the bottom in 30m of water. I dived down to around 23m and decided to return to the surface, casually. After ascending for a period of time (which felt long) I realised I was not getting to the surface and found out why. The enormous eddies behind the rock extending for hundreds of meters were sending spiralling currents downwards as also witnessed by small trapped air bubbles spiralling down. I shat myself and put the pace on for the surface and made it only thanks to my freediving fins, experience and fitness. Respect for the ocean

Craig's picture
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Craig commented Monday, 7 Jan 2019 at 9:52am

That's incredible and super scary. Wow.

gcart's picture
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gcart commented Friday, 4 Jan 2019 at 10:57am

Great analysis Craig , any similar data available for us over here on the West - between the capes ? Given that it has been a cooler than average summer so far , with consistent S/SE wind trend , the highs seem to be coming in at more northern latitudes..

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 1:33pm

Yep, you can access the data here: http://oceancurrent.imos.org.au/index.php

SST wise it looks cooler off the northern end of the Cape which would be a result of upwelling. 18deg or so? You can also see the warmer Leeuwin Current further offshore as well.

joakse's picture
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joakse commented Friday, 4 Jan 2019 at 1:26pm

Took my pool thermometer down to the beach this morning. 16 degrees. Wowsers. I guess the positive is there are definitely less people in the surf or they're in and out for a quick hour session. Bloody cold and windy here.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 1:28pm

Wow, where you located? Port region?

joakse's picture
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joakse commented Friday, 4 Jan 2019 at 2:02pm

Yep. Interesting as the BOM water temp shows high teens to low 20s. Not even close here and has been sitting at this temp for at least 10 days. Maybe offshore at the buoy it could be warmer. We have the trifecta...cold water, red weed and blue bottles...oh plus endless NE winds.

Craig's picture
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Craig commented Friday, 4 Jan 2019 at 2:04pm

Here's 2nd of Jan!

thermalben's picture
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thermalben commented Friday, 4 Jan 2019 at 1:30pm

Jeez, even Vicco beaches are still 19 degrees!

Cp's picture
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Cp commented Friday, 4 Jan 2019 at 6:26pm

Great read Craig. I went for a dive and a surf around gerringong yesterday. Crappy dive in the morning - next to no visibility in both shallow and deep water. Then an afternoon surf in boardies for a couple of hours in what looked like crystal clear water from above. Obviously deceiving.

Distracted's picture
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Distracted commented Saturday, 5 Jan 2019 at 7:17am

Craig, re the water colour. I wonder if it is also partly a seasonal factor. On the lower MNC, there are patches of weed being moved around by the wind but they don’t seem to be getting bigger and are mixed in with pools of very cold relatively clear water.
I think that the really cold green upwelling water that is filled with weed, jellies and Sea hares may occur more in spring when the upwellings coincides with rising air temp and the phytoplankton is ready to bloom. Now might be too late in the season for it to really bloom?

Groper's picture
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Groper commented Saturday, 5 Jan 2019 at 7:45am

Laurieton upwelling is well researched and strongly influences the coastline to the south.
Check out Trapped Coastal Waves for another interesting coastal process not only in terms of water temperature but also sea level heights. Could add up to another 50cm of water depth to a break.

thermalben's picture
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thermalben commented Saturday, 5 Jan 2019 at 9:14am

We’ve discussed coastal trapped waves before, not a dedicated article though it’s mentioned in the comments in this one below (which has other interesting info).

https://www.swellnet.com/news/swellnet-analysis/2016/04/19/inverse-barom...

big wave dave's picture
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big wave dave commented Saturday, 5 Jan 2019 at 8:59am

hi Ben. I'm in South West Rocks and have noticed that these black NE'ers really crank up overnight, which is counter intuitive for me. I would have thought that the sea breeze would be strongest when the temp difference between sea and land is greatest ie early/mid arvo.
Any theories?
ps-very cool article and comments. Love that stuff...

thermalben's picture
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thermalben commented Saturday, 5 Jan 2019 at 9:16am

BWD, you’re under the influence of a gradient wind right now. Because of your position relative to the common migratory pattern of Tasman high pressure systems, it occurs more often in your neck of the woods than further north (though not always the case). As per the forecaster notes, the wind was expected to be up early across your region.

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Feralkook commented Saturday, 5 Jan 2019 at 9:31am

Reading started me thinking whether there is a correlation between these upwelling events and shark presence. Given the increase in plankton I would have expected an increase in bait fish which would encourage the predators. Then someone's comments that upwelling is a fisho nightmare put a curve ball into that one.
I really appreciate these sorts of posts as it takes me into a different realm from my other interest of severe storms.
Cheers!

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Craig commented Saturday, 5 Jan 2019 at 9:45am

On that note I know there was some research a couple of years ago looking at the correlation between shark interactions and attacks in regions with high chlorophyll readings, not sure if it is still going but lots of reports have been in crystal clear water.

Distracted's picture
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Distracted commented Saturday, 5 Jan 2019 at 9:54am

Blindboy said it was better to have green water rather than toxic red tides, however, the green water can occasionally have localised negative impacts on coastal water bodies.
When there is a Red weed bloom following the green water, sustained nor’easters can drive the weed up into shallow tidal creeks where it then dies in the shallow hot water. If there is enough it can cause a deoxygenated water event as the decomposing weed is broken down by organisms that consume all the available oxygen. This results in a localised fish kill including shellfish and yabbies.

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Lanky Dean commented Saturday, 5 Jan 2019 at 3:43pm

Seen this scenario first hand, man its spooky .......

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STRATTOS28 commented Saturday, 5 Jan 2019 at 3:35pm

Very interesting reading great article and also some more knowledge in the comments ! I surf everyday here in sydney and those severe drop in water temp really seems to always occur overnite maybe also pushed by new buidling NE windswell... all week water been beautiful and this morning it was freezing

thermalben's picture
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thermalben commented Saturday, 5 Jan 2019 at 4:11pm
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Craig commented Tuesday, 8 Jan 2019 at 1:06pm

Crowdy Head dropped to a freezing 15.25deg Saturday night.. The upwelling wasn't picked up by many of the other buoys.

freeride76's picture
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freeride76 commented Tuesday, 8 Jan 2019 at 2:32pm

I'd say inshore water temps in Ballina are now well below 20......maybe 18-19

Blowin's picture
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Blowin commented Tuesday, 8 Jan 2019 at 3:26pm

Warmer here.

Just saw a thumping bull mahi at the boat ramp. Fish everywhere. Had a noah do a u - turn a couple of metres in front of me on the paddle out this morning.

Surf was shit though , should’ve gone fishing.

Craig's picture
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Craig commented Tuesday, 8 Jan 2019 at 3:26pm

Yeah southerly has brought in the warmer water back to Sydney, though still probably 20, up from the weekends 16 or so.

freeride76's picture
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freeride76 commented Tuesday, 8 Jan 2019 at 4:05pm

few days before Christmas I went for a midday fish on the low tide change.
10 mins later I was back at the Camry with a 10kilo jew.

2 weeks later on the same tide change I did exactly the same thing.

Got to admit that was far more exciting than any of the either slop surfs or super crowded surfs I've had during this never ending pattern of onshore winds and 3ft E swell.

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Blowin commented Tuesday, 8 Jan 2019 at 5:17pm

Not sure how I got there , but I was reading an old surf report you’d done fora magazine in your area and there was a photo of a nice tunny you’d caught flicking soft plastics , now it’s dialing in the Xmas Jew bite.

Happy days.

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qbctm commented Tuesday, 8 Jan 2019 at 3:30pm

Down at Werri a few days after Chrissy and I walked in for a surf in boardies...got up to my thighs and walked out ...bloody winter cold..must've been around 16c or less

love youse all ...TM

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Craig commented Tuesday, 15 Jan 2019 at 2:31pm

Those surfing since last week would of noticed that the southerly change and lack of north-easters saw the warm clear water move back in, kicking back to 22-23 deg in Sydney. We'll see the upwelling kick back in over the coming days again, so don't put away the rubber just yet.

thermalben's picture
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thermalben commented Wednesday, 23 Jan 2019 at 6:43am

Incredible SSTs recorded at the Byron buoy over the last few days, peaking at 27.95 degrees on Sunday afternoon.
​​​​​​​

freeride76's picture
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freeride76 commented Wednesday, 23 Jan 2019 at 8:35am

it's been a very strong downhill run from the EAC lately.....which has also had the effect of moderating the strength of the NE flow.

Weirdly, wind velocities from the NE have been stronger at Ballina airport, only a few K inland than at the beach.

we'll see if that warm eddy is strong enough to resist upwelling over the next few days of predicted 20knot nor-easters.

Also, as has been pointed out before the Byron Waverider Buoy is in 60m of water (I think 3 or 4 nm out), due east of Ballina bar.

The water temp has no relation to inshore temps either at Byron Bay or Ballina beaches.

thermalben's picture
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thermalben commented Saturday, 2 Feb 2019 at 8:24am

Water temps are the Coffs Harbour buoy (orange line in the graph below) jumped from 21.2 degrees to 26.9 degrees in the space of one hour (yesterday, between 1am and 2am).

Of course this is some distance offshore and not representative of temps in the surf zone, but it's a fascinating insight as to small scale SST variability.

​​​​​​​

This was around the same time that a prolonged synoptic N'ly wind finally abated to under 10kts, preceding a gusty S'ly change (though, the northerlies did ease a few hours earlier, and the change was still six hours away). 

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Dan K commented Friday, 8 Feb 2019 at 5:46am

How reliable is the MHL data for sea temps? I use it quite a lot to gauge temps for chasing pelagics where I live, but this morning there's been a spike which remains fairly consistent with Coffs Harbour reaching 32 degrees! Is that even possible?
Thoughts Ben, Craig or anyone else up to speed with MHL data and current temps in general?

thermalben's picture
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thermalben commented Friday, 8 Feb 2019 at 5:57am

Well spotted.

Coupla of points:

1. Actual temp data should be accurate, unless there is a technical fault with the onboard thermometer. Could buoy fouling affect the accuracy of the data? I'm not sure but will have a look to see if there's any information on this.

2. As you're probably aware, most buoys are anywhere from 2-12km off the mainland, so they're usually recording SST at or near to the shelf, which is sometimes not directly related to SST in the nearshore region. 

3. A concurrent increase in SST happened at the Crowdy Head buoy (see image below), and the temp range was much bigger. Coffs Harbour jumped four degrees from from 28 to 32; Crowdy Head jumped seven degrees from 19 to 26 (!).

4. CSIRO/IMOS satellite derived data only goes up to 28 degrees. Yesterday's data shows a broad region of very warm water with several areas of 28+ degrees. I'm skeptical, but in the absence of any other information, I suppose it's plausible and can't be ruled out.


5. Gut feel is that it's not accurate, mainly because of the sustained nature of the 32 degree reading (thus far, anyway). Crowdy Head spiked to 26 degrees and then dropped back to 22 degrees within a few hours. I know this data is not quality controlled in real time, so I'll ask MHL what they think.

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Dan K commented Friday, 8 Feb 2019 at 6:17am

Thanks for the response Ben
I'm in Forster so my go-to is the Crowdy data (also known as the upwell coast haha!)
I saw the Crowdy spike coincided with the spike at Coffs and thought there was a chance it just might be correct - will wait to hear from what feedback you receive from MHL. Cheers

thermalben's picture
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thermalben commented Friday, 8 Feb 2019 at 11:19am

Alrighty! Just heard back from Mark at MHL (for reference, the data collection is funded by the NSW Office of Environment and Heritage, and managed by MHL).

"There was also a sudden jump in SST at Coffs Harbour back on 1 February from 21 to 27 degrees in one hour. The QC process identified a corrupt record around that time but the 27 degree SST was possible and tied in with the strong EAC and SST charts on the BOM’s Marine and Ocean web pages. This latest rise on 7 February from 28 to 32 degrees seems a bit extreme so we will monitor the records in more detail. Based on experience the SST sensor should not be affected greatly by fouling on the buoy and we have had only one SST sensor fail in the past although the results were very erratic from hour to hour on that occasion which clearly indicated the sensor had failed.

The Crowdy Head data seems OK. Based on the BOM’s SST charts there has been a cool pool of water along the coastline north of around Forster for the last couple of weeks and the temperatures recorded by the Crowdy buoy seem to reflect some upwelling from time to time."

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Blowin commented Friday, 8 Feb 2019 at 11:32am

27 degrees a few kms offshore here this morning. Current was so blue it was purple. It was also moving South so fast it was causing slight whirlpools in 55 metres of water. Saw a couple of flying fish but fuck all bait around.

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Craig commented Friday, 8 Feb 2019 at 11:32am

Nuts, how's the boat negotiate the currents?

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Blowin commented Friday, 8 Feb 2019 at 11:42am

No dramas. Feels like you’re driving uphill heading into it.

Saw a couple of fellas kayak fishing out there too. Not as wide , but still hectic enough in a plastic pool toy that sits 6 inches above the waterline. I’ve seen dorsal fins way taller than that out there.

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simba commented Friday, 8 Feb 2019 at 1:14pm

Purple water,yohooo,,,got to love the colour purple...........go for a drift dive out there Blowin,like being in outer space........never know what you will see.
Temps have jumped here a fair bit in close.Time to fish for mackeral.

simba

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Blowin commented Friday, 8 Feb 2019 at 1:54pm

Simba - I’ve got a fair idea what I MIGHT see , that’s why I’m not in a hurry to jump over the side out there.

On my own out there anyway , so it probably won’t be happening. I’ve got my fingers crossed for a wahoo. I’ve never caught one and it’s on the bucket list. You’d have to be lucky around here , I suppose , but I know they get them every now and again.

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simba commented Friday, 8 Feb 2019 at 2:42pm

Mate just drift with the boat,if its as clear as i think you will have plenty of time to get back in the boat cause a 12ft tiger will look about an inch long when you see it,but obviously have someone in the boat if you can.Got any bombies rising up down there?....cause wahoo love that sort of thing.

simba