MJO rising

Craig Brokensha
Swellnet Analysis

Here we are, deep in the middle of summer with warm waters gracing most of the Australian coastline plus regular episodes of unbearable heat.

Besides a good run of trade-swell into the end of November and early December, the Gold Coast has been devoid of any decent swell until last week.

While last week's moderate to large S/SE groundswell was a touch out of season (more so autumn and winter), we're expected to move into a more seasonal period of tropical activity later this week.

This will be related to an active phase of the Madden Julian Oscillation (MJO) drifting in from the west.

The MJO is a wave of tropical activity that propagates eastward around the globe, going through certain strengthening and weakening phases along the way.

While tropical lows can form at any time during summer and autumn, the MJO enhances this by bringing increased instability, convection, and storms - the foundations for tropical lows. The more active the MJO is, the more instability and propensity for tropical storms.

The MJO is monitored and forecast out to two weeks by various weather agencies around the world, and can be visualised on the charts shown below.

While it looks quite complicated, it's actually fairly simple. The globe is set up into eight rough sections, and if you imagine looking at the diagram from the south pole, you can see Australia falls in the middle of section 4/5 in the Maritime Continent, 7/6 covers the Pacific Ocean, 8 America, 1 Africa and then back to the Indian Ocean 2/3.

The end of the blue line is where the MJO is currently placed around the globe (as of 20th January), with it travelling anti-clockwise (eastward) around the equator.

The strength of the MJO is signified by how far away from the centre the line is, and over the past fortnight we've seen the MJO very active across the Indonesian region. This has resulted in the formation of multiple cyclones, namely Ava, Irving and Berguitta last week.

The MJO is now moving in across northern Australia and current forecasts have it pushing further east through this week while maintaining strength, onwards towards the Western Pacific.

This will likely result in the formation of a tropical cyclone off north-west Australia, but of greater interest to us is if we see any developments in the Coral Sea.

Current indications are promising with a strong high pressure system forecast to stall over New Zealand and the eastern Tasman Sea, while a couple of tropical lows form on its northern flank setting up a broad and healthy trade-fetch.

This will result in easterly trade-swell building from the weekend across the East Coast, further through next week with larger surf dependent on how the tropical lows play out. We're expected to see these lows drifting south squeezing the high further, but whether this is closer to the Australian mainland or above New Zealand is still unclear.

Additional lows within the monsoon trough labelled in the above diagram will inject further energy into the region and likely also maintain activity for some time yet.

Keep an eye on Ben and Craig's Forecaster Notes over the coming fortnight for regular updates regarding the timing, size and local winds around this summer swell event.

Comments

Nick Bone's picture
Nick Bone's picture
Nick Bone commented Tuesday, 23 Jan 2018 at 9:59am

Excellent title

I am the bone

stunet's picture
stunet's picture
stunet commented Tuesday, 23 Jan 2018 at 10:13am

Giving your age away Nick.

carvin60's picture
carvin60's picture
carvin60 commented Tuesday, 23 Jan 2018 at 11:36am

Rising,Rising.Gotta keep on rising.

Woof woof 41's picture
Woof woof 41's picture
Woof woof 41 commented Tuesday, 23 Jan 2018 at 4:58pm

I've been singing the fkn Doors all day long now!

Craig's picture
Craig's picture
Craig commented Tuesday, 23 Jan 2018 at 5:01pm

Haha.

Woof woof 41's picture
Woof woof 41's picture
Woof woof 41 commented Tuesday, 23 Jan 2018 at 1:51pm

It all looks pretty straight forward to me...
We are all going surfing simple as that.

Craig's picture
Craig's picture
Craig commented Tuesday, 23 Jan 2018 at 1:59pm

Did someone say monsoon? Ulu's cave..

goofyfoot's picture
goofyfoot's picture
goofyfoot commented Tuesday, 23 Jan 2018 at 2:00pm

Holy Fuck!!

Hati Hati!

Tim Bonython's picture
Tim Bonython's picture
Tim Bonython commented Tuesday, 23 Jan 2018 at 4:02pm

Perfect, I'm back Monday.

Clam's picture
Clam's picture
Clam commented Tuesday, 23 Jan 2018 at 6:32pm

Who is madden julian anyway ?

"The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30- to 90-day) variability in the tropical atmosphere. It was discovered in 1971 by Roland Madden and Paul Julian of the American National Center for Atmospheric Research (NCAR). It is a large-scale coupling between atmospheric circulation and tropical deep convection.[1][2] Unlike a standing pattern like the El Niño Southern Oscillation (ENSO), the Madden–Julian oscillation is a traveling pattern that propagates eastward at approximately 4 to 8 m/s (14 to 29 km/h, 9 to 18 mph), through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself most clearly as anomalous rainfall.

The Madden–Julian oscillation is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian and Pacific Ocean. The anomalous rainfall is usually first evident over the western Indian Ocean, and remains evident as it propagates over the very warm ocean waters of the western and central tropical Pacific. This pattern of tropical rainfall then generally becomes nondescript as it moves over the cooler ocean waters of the eastern Pacific (except over the region of warmer water off the west coast of Central America) but occasionally reappears at low amplitude over the tropical Atlantic and higher amplitude over the Indian Ocean. The wet phase of enhanced convection and precipitation is followed by a dry phase where thunderstorm activity is suppressed. Each cycle lasts approximately 30–60 days. Because of this pattern, the Madden–Julian oscillation is also known as the 30- to 60-day oscillation, 30- to 60-day wave, or intraseasonal oscillation. "

Further reading thanks Wikipedia:
https://en.m.wikipedia.org/wiki/Madden%E2%80%93Julian_oscillation

eat-your-vegies's picture
eat-your-vegies's picture
eat-your-vegies commented Tuesday, 23 Jan 2018 at 11:49pm

Those stairs got washed away a year or 2 ago.
I think I might try another exit strategy if I were them.

nicko74's picture
nicko74's picture
nicko74 commented Wednesday, 24 Jan 2018 at 12:05am

Wow! Thanks for that follow up Clam on what was already a fascinating read .

fletch032's picture
fletch032's picture
fletch032 commented Saturday, 27 Jan 2018 at 10:42pm

Woooooohooooooo

Got me thinking about Cyclones and whilst this next episode of tropical activity does not look like it will come anywhere close, it made me reminisce on the perfection that was produced by TC Wati back in late March/early April 2006......and going further back past Wati was another cracker.....TC Sose in April 2001......oh baby love a good cyclone swell!

southey's picture
southey's picture
southey commented Saturday, 27 Jan 2018 at 11:47pm

Not sure if i've read this somewhere long ago or its just an observation of sorts .
But the MJO is Rhythmic in its circulation patterns . In otherwords its wavelength or pattern of circling the globe speed , repeat appearance .
It has some sort of connection to the Lunar cycle and is amplified dramatically when its timing is matched with a excessively warm SST area below and more importantly a Atmospheric tide that usually occurs around rarer so called super moons etc .I'm talking stronger tidal effects from Lunar orbit , Earth Orbit , in relation to the sun and less so other planets alignements . Most of which can be seperated into derivatives or sectional portions of Milankovitch cycles . For fear of boring you to death i'll stop there . But not before suggesting that much is to be learnt from Solar sunspot cycles and a phenomena refered to as Solar winds , which are often described as differing variations in ionising nuclei particles . Anyway they are said to influence cloud cover / seeding , no i'm not making this up the Solar winds are visible at high latitudes , in the form of the aurora borealis & aurora australis .
Anyhow the models had a hard on for The Coral sea / tasman , but now appears that The models have the MJO going bezerk out in the middle of the Western Pacific . Whether or not that delivers from afar to NNSW/ SEQ remains to be seen .
Back in my hole .

" SA's Reserve Capacity "

Craig's picture
Craig's picture
Craig commented Tuesday, 30 Jan 2018 at 2:51pm

Bit of rain around North West WA..

shoredump's picture
shoredump's picture
shoredump commented Sunday, 25 Feb 2018 at 2:59pm

The MJO is clocking good time down the back straight, doing it’s best to make it back in time for the comp

Craig's picture
Craig's picture
Craig commented Thursday, 29 Nov 2018 at 2:24pm

Looks like we'll be in for a new stregthened phase of the MJO over the next fortnight, hence the TC showing on the long-range charts.

Craig's picture
Craig's picture
Craig commented Thursday, 26 Dec 2019 at 12:54pm

Besides the current developments in the Coral Sea it looks like we'll see a bit of action off WA's north in the coming fortnight as well as the MJO comes around with more strength (red-orange wiggles in sector 3/4).

The IOD has finally released its hold on the monsoon trough it looks with it set to arrive hopefully in the coming 2-3 weeks.

Halfscousehalfcockneyfullaussie's picture
Halfscousehalfcockneyfullaussie's picture
Halfscousehalfc... commented Thursday, 26 Dec 2019 at 8:46pm

so glad that super strong super long positive IOD has gone. Bring on the rain and swell Huey