August

[Nick Carroll]

good god have we all gone insane.

don's got a bomb going off above NZ. oldbloke's got an ECL turning Shearer's chickens' lives to shit again.

it's making about as much sense as the ESPN tour debacle.

what about a crappy SE windswell for next Monday.

[oldman]

what about a crappy SE windswell for next Monday.

Yep, that's in there as well.

That's what I mean though Nick, just can't give much meaning to it all because it is so variable at the moment.

Just to prove I'm not completely insane, here's a pic of the NZ Met Bureau's prognostications, which you may note differ a fair bit from GFS and EC.

ECL 07_08_09.gif (68.19 KiB) Viewed 5430 times

[thermalben]

Just to prove I'm not completely insane, here's a pic of the NZ Met Bureau's prognostications, which you may note differ a fair bit from GFS and EC.

Actually, the NZ Met Bureau don't run their own model - I am pretty sure that this is a replot of the ECMWF model. It's hard to compare though (just to be sure), as the NZ Met Bureau have 6 hourly time steps, and update the model four times a day (the chart above is from the 18Z run, at T+84). Other external EC sources update twice a day (00Z, 12Z) and offer the data in 24 hour time steps.

[oldman]

Actually, the NZ Met Bureau don't run their own model - I am pretty sure that this is a replot of the ECMWF model. It's hard to compare though (just to be sure), as the NZ Met Bureau have 6 hourly time steps, and update the model four times a day (the chart above is from the 18Z run, at T+84). Other external EC sources update twice a day (00Z, 12Z) and offer the data in 24 hour time steps.

Thanks Ben. From the NZ site

"These weather forecast charts are generated by software written and maintained by James McGregor. The data used is obtained from the United States National Weather Service. These charts are updated approximately every 6 hours and provide forecasts up to 180h ahead of the time they were issued.

It takes six hours to generate all the forecasts and so the issue time should be between 6-12 hours behind the current time."

Base data is the same. Don't know what James McGregor's software does, but it is the area of ocean to the east and south of oz that these charts cover that really interest me. Hate the way the Oz BOM cuts off a big area of our swell window.

[Donweather]

Doesn't really matter where the chart comes from.......as long as it's consistent with the other models I couldn't care if it was written/developed by Fred Flintstone. It's showing what I want to see. I damn nice fetch squeezing between a semi-stationary high pressure system and a low on it's northern flank.

All of this ABOVE that cnut of an island out there and as far as I'm concerned that's GOLD for us at this time of year.

Enough said really.

Oh and Nick, don't get me wrong, it's not going to be huge, nor have the power that you guys saw last week/weekend, but as I said above, for August in SE Qld, it's damn nice to see let me tell you.

[Donweather]

Hey Donw, (capo di tutti capi) it's a bit hard to get excited by next week's swell when the charts are so dynamic.

From Monday to this morning the charts have changed a lot, just about every run.

and while the low over the top of NZ looks like producing the goods, we may not see any of it, and you too, because the charts are now showing a pretty serious east coast low developing just off Byron, which will create a whole different scenario and some wild swell, winds and rain.

Oldman, not sure why you've referenced me as "Boss of all Bosses"? Anyway, as to the charts, most models are now aligning quite well with respect to the formation of the semi-stationary high to the east of NZ and a low on it's northern flank for this weekend, so I'm fairly confident we're likely to see some E'ly swell from this girl early-mid next week. It's just a question on size now. Agree that EC isn't showing as intense a low, but nevertheless it still sets up a good, semi-stationary fetch over a reasonable distance and this will produce, no doubt.....just need some more model runs to firm up size, but I'd be hazarding a guess it will be somewhere in the 4-6ft class at this stage.

As for your Tasman low, she's perfectly positioned south of us to create some damn fine looking SW winds later in the weekend, swinging more S'ly into Monday (points!!!), and as she drifts offshore on Tuesday, this is when she's looking the goods. Granted local winds for next week are still the big variable in the equation, but I'm not too worried given that it's hard to see the Tasman low drifting northwards, giving us too much grief with onshore winds up here.

[Donweather]

And I have to agree with Ben. That chart above from Metvuw does look very similar to the 12z EC model run output from earlier this morning. I'd suggest checking the 00z runs between EC and Metvuw later this afternoon then to see if they're exactly the same.

Nice to know one can get more detailed EC charts and greater frequency of model runs that's for sure. Curious as to where this James character get's his data from as I thought one had to pay serious amounts of cash to get this level of detail from the EC models?

[thermalben]

Thanks Ben. From the NZ site

"These weather forecast charts are generated by software written and maintained by James McGregor. The data used is obtained from the United States National Weather Service. These charts are updated approximately every 6 hours and provide forecasts up to 180h ahead of the time they were issued.

It takes six hours to generate all the forecasts and so the issue time should be between 6-12 hours behind the current time."

Base data is the same. Don't know what James McGregor's software does, but it is the area of ocean to the east and south of oz that these charts cover that really interest me. Hate the way the Oz BOM cuts off a big area of our swell window.

Thanks oldman - I got my NZ met companies wrong - I was thinking of Metra (and not the NZ Met Bureau), who purchase high res EC data - although, the NZ Met Bureau would also have access to EC data, 4 times a day, at 6 hourly steps. The model run looked remarkably similar to EC too, rather than GFS, whom it appears they are sourcing their base data from. James McGregor's software merely plots out the data and makes it look pretty.

[thermalben]

Curious as to where this James character get's his data from as I thought one had to pay serious amounts of cash to get this level of detail from the EC models?

All met bureaus around the world are given a number of high res EC fields for operational use (as per an agreement with the WMO). However, the licensing arrangements to redistribute this data are very complex and restrictive. Buying raw EC data is prohibitively expensive, and only affordable to very large met agencies (like Metra, hence my earlier assumption above).

[Donweather]

So you reckon it's (Metvuw) GFS model based then Ben?

[oldman]

James McGregor's software merely plots out the data and makes it look pretty.

Thought so.

Oldman, not sure why you've referenced me as "Boss of all Bosses"?

A term of affection and respect DonW (spoken in a bowing and deferential way).

From the mafia tradition of calling the bosses "Don", as in Don Corleone.

Capo di tutti capi, the big mafia boss. In my mind, most commonly associated with the term Don Bartholemew, from the Simpson's episdoe where Fat Tony tries to get Bart to take the fall for all their activities, and they refer to him as capo di tutti capi.

Oh yeah, also that Mario Puzo book, The Mafia.

Just anyone going by the name Don will evoke these tangential stream of nonsense thoughts.

Edit: Of course, Mario Puzo's novel was called The Godfather, not The Mafia.

[thermalben]

Yeah, it probably is - and in hindsight, the image oldman put up was the 18Z run, which I try to avoid at all costs - lots of quirky things pop up on the 18Z and 6Z run that usually vanish by the next model run. So, it's very possible that GFS intensified that system rapidly from the 12Z run. We'll all know later this afternoon which way it goes!

[Nick Carroll]

Don't know what James McGregor's software does

It creates splendid-looking low pressure systems where they won't be appearing, just in order to drive Australian surfers mad.

Honestly, New Zealand has a lot to answer for. If it's not the island getting in the way, it's James's software telling us porkies.

[oldman]

lots of quirky things pop up on the 18Z and 6Z run that usually vanish by the next model run.

Ah well, that's the difference between someone who knows what they are talking about and, well, me.

The re-runs have been moving around a lot on these charts in the last few days, and perhaps your comment explains the dynamic changes I have been noting.

Unfortunately that is a bit of information that will probably fall out of my head.

I'll see if I can find where it tells me which 'run' it is and try to follow your advice.

It creates splendid-looking low pressure systems where they won't be appearing, just in order to drive Australian surfers mad.

The triumph of hope over experience. Hope this is all sending you crazy Nick. Sounds like you are squirming in your seat waiting for the next swell event.

Honestly, New Zealand has a lot to answer for. If it's not the island getting in the way, it's James's software telling us porkies

And so much more besides.

[SAsurfa]

I'll see if I can find where it tells me which 'run' it is and try to follow your advice.

Looking back on your previous posted picture the model output time is shown after the heading "Forecasts issued at:" 1800 GMT (18Z )

Oh also in the big bold saying "Valid for:- 1800"

1200 is the 12Z which is 10pm Local Sydney time and 0000 is 00Z which is 10am Local Sydney Time.

1800 is 4am Local Sydney time and 0600 is 4pm Local Sydney time.

[puurri]

GMT (Greenwich observatory Mean Time) is 0000HRS as the international time zero reference point = zero degree of longitude = Z = ZULU (military parlance eh Longun?)

[oldman]

Hey woah, slow down a bit there!

So 18z is when it says "Issued at 1800 ...."

And 6Z, is when it says "Issued at 0600 ....."

And they are the ones that I should be careful of.

How the hell am I gonna remember that

Reminds me of the last SAS training I went on with a room full of freaking programmers, and 2 HR types trying to keep up.

Oh also in the big bold saying "Valid for:- 1800"

You were going so well. That was the picture for the forecast at 1800 Saturday NZST.

Much appreciated gentlemen, as usual.

[SAsurfa]

You were going so well. That was the picture for the forecast at 1800 Saturday NZST.

Indeed it is, haha, but looks like you get the gist

Have one of these