Experimental Forecast Winter 2009

filski

Pool Room
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Mar 14, 2011
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Sorry, bloddy late. Unfortunately I'm been climbing a mountain at work for the last 8 weeks or so. Long weekend this weekend (well for the rest of the UK, I'm going into work Monday)so I'll try to get up to speed quickly.

First up, a link to last years thread. I won't explain it all again, go there for the principles.
https://www.ski.com.au/xf/posts/401969&page=1#Post401969

So straight into it. First some images all in one place for reference, then the analysis (tomorrow). Look for analogue years. Note the years that don't match and look at how the seasons panned out and look for similairties to this year.

The cornerstone of the forecast - the AAO. It's strongly positive but forcast to dig negative by mid May. More on this later.
month.aao.gif

aao.sprd2.gif


SOI is moving in opposite direction to last year
soi30.png


Nino 3.4 is slightly more positive than last year and looking neutral for the bulk of the season
ssta.nino3.4.fcst.1apr2009.gif


Indian Ocean Dipole is negative but forecast to turn positive by majority of the ensembles
ssta.eio.fcst.1apr2009.gif


Precipitation is currently just on the weeter side of average for the season but I expect that to change
tprep.glob.JJA09.1apr2009.gif


Air temps expected to be below average for the duration
temp2.glob.JJA09.1apr2009.gif


Sea surface temp anomalies over the last 2 months - less chance of cutoff lows early this season
sst_anomaly_2m.gif


MJO, trending towards phase 1
ensplume_full.gif


OLR time plot - the blue at the bottom near 120E is what gave us recent snowfall, following is a dry spell but looks weakish. Any questions on this one?
olr_hov_last180days.gif


That'll do for now, have a think about it. It's different to last year but is it good or bad?
Back tomorrow.
 
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filski

Pool Room
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Again, this method looks at large scale weather phenomenon, at least to start with. These have cycles of a sort and, depending on what stage they are at/ the influence of the of other cycles, the goal is to try and pick the progression from a start point. From there an educated guess can be made about individual systems between 1-4 weeks can be made. The hard part is where the long term cycles break down and undergo sudden changes as it did last year in July. This is where looking for analogue - similar - years come in. Sticking with a visual analysis this year while I attempt to learn enough about statistics to give it a good go next year.

Anyway, looking at the first chart I'm going to single out 82, 89, 94, 99, & 2000 to start with, based on last 6months and predicted trend. 2002 deserves a mention too.

Looking at SOI and Nino 3.4 together
nino34weekly_Allserie_figure.png

I'd refine that selection further to exclude 82 based on Nino 3.4 not expected to go so strongly positive, 89 stays in just, 94 is going the wrong direction but hovering around neutral... still in, 99 is out, 2000 is borderline, 2002 is a good match. Add 85-86 and 96-97 though.

Years excluded above are not totally excluded, just not a match for the 2 indexs so far. Might come back.



Onto the indian ocean and a harder to read graph. Looking above its a short term positive trend...
dmiweekly_Allserie_figure.png


82 is back in, 89 is out, most of the others don't have a good match either till 2007. You could look at 91 but there is not a lot of support.

So far if I was going to pick a year I favour 82 and maybe 2002. Taking a flick around other indexes backs those up to an extent. However 1982 was one of the strongest El Ninos of recent times - quite different to conditions today. 2002-3 was also a moderate El Nino but 2001-2 was a weak la nina. We are just coming out of La nina. 2002 and 1982 couldn't be more different though in terms of snow.

Here goes based on what I've read. I feel we are closer to a 2002 type year. No charts have been consulted other than what is posted in both threads.

The feature of the year will be the interaction of high systems to the south interacting with a moist flow from NW Australia. This contrasts with easterly systems or cut off lows. This sort of year can be quite a good one with regular snow falls and little melt from too humid or warm conditions.

Peak season depth 170-190cm.
Rest of May. Dry start to May with potential for snow around the 3rd week. Likely to have some natural snow around on opening weekend. The recent falls will largely melt though.
June. Steady start after the second week with a reasonable base by the end of the month. Pretty average conditions.
July. Going to get started after the first week with above average falls lasting into August.
August. Tailing off after the second week, the best falls are behind the season now.
Sept/Oct. Warmer temps and rain mean a quick end to the season as the indian ocean changes mode, ocean temps change and bring in more easterly weather.

Caveat - I've guessed a bit more of it this year than last and don't expect great success. Part of it is a lack of time to look at the weather closely and part is a lack of a strong signal. I'll update as I can and do a monthly review. I already know I'm pretty busy with work for much of May/June providing the current contracts don't go dead.
 
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wangster

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Oct 24, 2008
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Thanks for the effort and the forecast SF. I find it very interesting
thumbsup.gif
 
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Rush

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Jul 26, 2000
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Your problem is that the ENSO forecasts are at their least accurate at this time of year.

Good luck!
thumbsup.gif
 
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filski

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Early update... cocked up May already!
A strong block seems to be setting up for the foreseeable future sending all systems south.
 

Gerg

One of Us
Sep 8, 2001
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I think that's a liitle harsh. The current sys will peak over NZ and could deliver up to 100cm if all goes well. Next weekend's sys will peak over Perth and so miss us again. Things are pretty active for the time of year. The phase just needed to be a little different and you'd be spot on, no?

G.
 

Majikthise

Sage
Moderator
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Jan 1, 1970
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Second week of June looking pretty good. I think we'll allow you monthly amendments.
smile.gif
wink.gif
 
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filski

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Very very average success so far, more coincidence than skill.

Upcoming precip nothing to be pleased about.
tprep.glob.JJA09.1jun2009.gif


The forecast for the IOD and El Nino has turned out to be correct - sadly for India. Get your turns in during July and August.
 
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filski

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Bit more luck than skill if it is. Next challenge is to find some way of extracting data to recognize more subtle patterns. Visual analysis only goes so far.
 

Ski Tragic

Hard Yards
Jul 2, 2006
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Predicted on the 4th May

Schaden Freude said:
Peak season depth 170-190cm.
Rest of May. Dry start to May with potential for snow around the 3rd week. Likely to have some natural snow around on opening weekend. The recent falls will largely melt though.
June. Steady start after the second week with a reasonable base by the end of the month. Pretty average conditions.
July. Going to get started after the first week with above average falls lasting into August.
August. Tailing off after the second week, the best falls are behind the season now.
Sept/Oct. Warmer temps and rain mean a quick end to the season as the indian ocean changes mode, ocean temps change and bring in more easterly weather.

Pretty good prediction by my reckoning of whats happen this year on a monthly basis. Not above average falls for July but other info seems spot on. (IMHO)
Well Done
 
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filski

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Thanks for the support but let's be honest. It was a pretty vague prediction, not on purpose but I did say I was short on time this year.

15 words to describe July? If we were really critical you could pass the lot off as stating the average patterns for winter. The best chance of falls are always behind us in mid august.

Yes there is some science in the teleconnections. The el nino prediction was spot on and also guided the calls for post august. It also makes use of - let's face it - somewhat dubious methods. Some moon cycles, etc for example (note 1st, 2nd week pattern?).

I do have honest hopes to turn the method into something useful but it will take time to refine it. In the mean time I'd like to keep it real so will be more critical/ honest than you lot about how accurate it was. It'll be back again next year, hopefully without the horror run I had with work.
 

Taipan

Old n' Crusty
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Jul 5, 2001
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Good attempt SF. I know we disagree about climate change, but i have some glimmer of the complexity that you face.

You are basically attempting to solve problems where professional meteorologists cannot succeed beyond 96 hours on a regular basis.

I welcome all attempts to seek true understanding.
 

Majikthise

Sage
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you've fallen away a bit with september, peak snow depth very late this year and not as high as you stabbed for... however the 2002 call stacks up pretty well.
 
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