Indian Ocean in hyperdrive
Those who love all things bright and colourful will enjoy a quick scroll through the Indian Ocean WAMs for the coming fortnight.
One by one, blobs of purple and red are pulsing towards Western Australia and Indonesia in one of the most active storm periods seen in the last few years.
We've already got a large long-period south-west groundswell on the way for this Sunday, with the Rip Curl Padang Cup most likely being run, but the storm that generated this swell is nothing in comparison to what's forecast to develop over the coming two weeks.
Two successive amplifications of the Long Wave Trough (LWT) will move slowly across the southern Indian Ocean, the second being the real money maker, it's the stronger of the two and projecting well into the mid-latitudes.
Surface fronts and storms follow a similar path to the Long Wave Trough, and when it's amplified over a certain region we see these surface features strengthen and focus into the said region.
The storms actually take a path just west of where the LWT is amplified or subdued, as the surface weather lags the upper atmosphere which moves slowly eastward around the south pole.
An initial strong node is currently strengthening in the south-east Indian Ocean, resulting in a flurry of strengthening polar storms piggybacking each other south-west of Western Australia over the coming days. This will produce a large and active open ocean sea state for one final and very significant fetch of storm-force winds to move over, projected up and into the Great Australian Bight.
An XXL long-period groundswell will result for the southern Australian coastline this coming Tuesday, with Indonesia seeing an XL south-southwest groundswell on Thursday. Usually such swells are met with strong onshore winds across Western Australia, but in this case a strong high will quickly move in through Tuesday resulting in mostly light and variable winds across the state creating favourable conditions for those willing to tackle the monstrous conditions.
Margaret River looks to peak around 18-20ft, with larger waves at deepwater offshore reefs, and larger surf again on the more exposed southern coast. It's worth noting the Indonesian models are combining a couple of swells on Thursday and over-forecasting the size. Though in saying this, we're still due to see 12ft+ surf across exposed magnets under E/SE trades.
Now, the second stronger node of the Long Wave Trough will make its presence felt further north into the Indian Ocean and peak further west, resulting in the Southern Ocean storm track to protrude much further north than usual and with strength.
This will send back to back polar fronts close to Indonesia producing back to back XL groundswells in a run of swell not seen for at least a few years.
It's a little too early to dial down the specifics but we're looking at XL groundswell energy out of a south-west direction from early in the week starting the 23rd of July.
Confidence on such significant swells is high as the models have been consistent with the strong amplification of the LWT across the Indian Ocean.
Keep an eye on the Indonesian, Western – Southern Australian and Victorian forecaster notes over the coming fortnight for a clearer idea on the timing, size and local winds with each significant swell pulse.