Nias, Mentawai, South Sumatra forecast by Craig Brokensha (issued Tuesday 4th March)
Best Days: Every day over the coming period
This week (Mar 4 - 7 onwards)
First up, the coming week and a half is looking really good for surf in the Sumatran region.
Yesterday's pulse of inconsistent S/SW groundswell should of eased a touch into today but should remain fairly steady under light variable winds.
There's plenty more (slightly more consistent) swell on the way for the rest of the week as well, generated by a series of strong polar fronts pushing up from the Heard Island region towards WA late last week and over the weekend, just on the periphery of our southern swell window. Size wise we're looking at 3-4ft surf at breaks open to the south with the rare bigger bombs at times.
The direction will continue to be from the S/SW due to the storms firing up later in our swell window in the Eastern Indian Ocean.
The largest increase in S/SW groundswell is due through Friday and Saturday and it will be a mix of super long-range energy generated south-east of South Africa, mixed in with a more consistent swell from the Heard Island region.
This swell should build to a good 4-5ft+ across exposed breaks in the Ments (smaller north, bigger to the south) during Friday before easing slowly from a similar size Saturday.
This weekend onwards (Mar 8 onwards)
We're looking at a similar pulse of S/SW groundswell on Sunday to the pulse we saw yesterday across the Sumatran coastline, with a deep polar low firing up just west of where the remnants of Guito fired up.
This system won't be as long lived, but satellite observations confirm a fetch of 35-55kt SW winds being aimed through our southern swell window (pictured right).
A very inconsistent and medium sized S/SW groundswell should result and build to a solid 4-5ft across exposed locations in the Ments during Sunday, with smaller sets further north around Nias and bigger surf in Southern Sumatra.
Looking at the winds over the coming period and they should be generally light and variable, creating clean/glassy conditions in between local storms.
Looking longer term we're expected to see one more moderate sized S/SW groundswell into Tuesday/Wednesday next week from a couple of polar fronts piggybacking each other south-west of WA during the end of this week/weekend.
Beyond this a large blocking high will dominate the Indian Ocean resulting in a period of small to medium background swells from Friday 14th of March onwards.
Click here for the Mentawai forecast
Hi Craig - any chance of an update before Sunday?
Probably not sorry Maddog, was on the road yesterday so didn't get a chance to update.
Nothing has really changed.
Looks like a good moderate pulse of S/SW groundswell Sunday that will then ease slowly Monday from 3-5ft at spots exposed to the south swell.
Another pulse is due Tuesday afternoon that will hold well into Wednesday probably a bit smaller and in the 3-5ft range.
From then on there's nothing too major, but background swell should keep inconsistent 3ft sets hitting exposed locations, with a slightly bigger pulse for Monday the 17th.
Let us know how you go!
Thanks Craig - will do....
Hi Craig - just got back so thought I'd give you some feedback.
Pretty much spot on with the forecast. Monday thru Wed saw 3-5ft at most breaks with the exposed one's seeing a fair bit more size. Dipped Thursday morning but then up again late Thursday arvo which held into Friday but it was more inco than previous days.
From then on we hit the swell magnets. Sat and Sun in the 2-4ft range and as you predicted we got another little pulse Monday 17th. Tuesday and Wednesday back to 1-3ft with another pulse Thursday 20th.
Great trip - I'm surfed out....
Great to hear Maddog!
Period ahead isn't too flash so looks like you timed it well!
Update due soon? Leavin wed...
Looks like a sustained run of 2-4ft surf for the next 7-8 days with potentially some slightly bigger surf (4ft/maybe 4ft+) arriving around early-mid next week (tues 8th/wed 9th) and then 2-4ft after that.
Certainly been a very slow start to the Indo early season.
Should have an update tomorrow Roystein, but generally around what Don's said. Better swell from the weekend of the 12th if you're still around.
Ok thanks Craig, Sunday 13th last day. Patterns look a bit funky with that cyclone sitting in the middle. Hoping still some fluidity in the models. As long as it's not flat!!
I'm off to Simeulue from 8th to 18th April.
I've been checking the WAMS as that is about the limit of my forecasting abilities. A model to me is a small plastic Spitfire that gets put together with Airfix glue!
So from my very limited abilities and going from a bit of the advice above, its looks like 3-4 foot first few days, then Sat - Sun 12 - 13th the period goes up substantially to around 14 secs and size creeps up to 4-5 foot, then starts to drop away gain post 15, which is as far out as the WAMS go.
Am I in the ball park or not even playing the same fuckin' sport to use a gratuitous movie quote?
Bit far out to be confident about those dates yet palmymick, especially with the cyclone in the area, but you're around the mark, that's for sure. We'll have a closer look tomorrow.
Cheers Craig, much appreciated
May even see you there Palmymick.
Nice one Blowin. I'll have to split the Peak with ya!
Have you been before Palmymick ?
Nah never been but have had 2 mates go previously. One of them has been 3 times he reckons its that good. Both them raved about it, especially the lack of crowds and the Peak out front.