Isolated Frost
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Posts posted by Isolated Frost
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Nice chart: do you have the raw data for that?
Here you go.
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Just read what the very useful OPI team response, and then the replies saying 'back to square one' and 'gutted'.
As far as I can tell, the post simply confirmed a lot of what we thought, along with adding the IZE (which could also be useful for future), but the OPI-AO/CET correlation hasn't actually changed. Sub -1.5 OPIs have still provided pretty cold winters, and it's currently -2.43? Bon nuit.
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Utmost respect for the Met, but this is the OPI thread of course.
And anyway, if we went by the contingency forecasts... where's my below average NDJ last year?
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-2.45 with 120 hours of input to go
Considering that means it's had 624 hours of real data and 120 of forecasted data; so I think it's very much settled between -2.2 and -2.7; think everyone here would have took that on the 1st.
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That read to me like the most deep, romantic, Shakespearean poems would.
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I think most long term models are generally preset to a more mobile, traditional pattern and any notable differences will be tempered by its signals.
I'm sure the OPI and SAI will override some signals; and the general correlation is strong enough to suggest that.
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Its a nuisance in November. What is one supposed to do in 6 hours of darkness apart from watch tv and eat? But as others have said, it does seem appropriate during the festive season to have the sun setting early showing off peoples christmas lights and trees in the front room. Then when Christmas is out of the way the nights are drawing out again. Therefore Christmas acts as a welcome distraction.
Nothing like night walks. Get hammered? Astronomy?
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Personally it doesn't really matter too much, the hour is negligible- but I always like walking home at 4pm on December days, add to the festivities.
Mind you, it being dark at 9:30am would certainly be interesting. I can see the point of moving to CEST during Summer though, when it's light at 3am, and dark at 11.
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Why is the UK never coloured in? Is this as we are often on the edge of cold weather so harder to forecast?
EU are anti-British.
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12z OPI @ -2.20
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As the 00z today takes +168 to get to 00z 1st November, I'd say we've got 2-3 days of any possibility of a spread above 0.8-1.0 (i.e. values dipping below 2.0 or above 3.0), but I think we've got a reliable landing range which means the OPI is going to be the 2nd lowest in its 38 years of recording. And looking at OPI-DJF AO composites, OPI-DJF CET composites, that is, at the very least, a very good start if you're looking for cold this winter.
Of course there are many more pieces to the puzzle, but we're at no disadvantage to have one of the lowest OPI values on record.
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-2.37 this morning. Almost identical to yesterday's value following the 12Z.
Looks like the wild swings are over and we are closing in on a final figure.
The last 4 values before were
-1.89
-2.99
-2.75
-2.39
I'd be wary to say we're closing in, I think once we get to +96 (27th) we can be a lot more sure of a 0.2-0.4 landing figure; but the next couple days will change a bit I think.
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-2.39, a third consecutive drop if we compare the 12z day by day (which we should really). Just 8 more now...
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Curiously most of you will be waking up to a -2.99 OPI, based on the 0z. With the missing GFS data issues and what not, I'd say the spread is possibly larger than usual.
But then again, I don't have a clue at all, nice to see it dip so negative though.
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Love your 4.9c S,Murr, Any chance on giving your reasons
It was gonna be 3.9c but his trainer told him not to for our good.
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According to the terminology used in explaining the OPI; the 0z coming up tomorrow morning will be the first run to factor in all of October (1-21 October actual, 22-31 forecast). I think from there, we can reach a more reliable and tight spread of solutions. If it's -2.13 at the end of the month, virtual pints on me.
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The better the 12z, the bigger fall you're setting yourself up for- it's all a trap!
But seriously, it does look like another sub -2.5 run, just hoping for the next 10 days it can hold steady around here. Landing range between -1.5 and -2.5 I'd say.
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There's been 48 years of OPI recording, and in 8 of them, the OPI has been sub -1 (of course only one year, 2009, was sub -2)
OPI (Winter CET anomaly)
2009: -3.15 (-2.1c)
1985: -1.9 (-1.6c)
1984: -1.8 (-1.8c)
1978: -1.8 (-2.9c)
1976: -1.75 (-1.2c)
2012: -1.65 (-0.7c)
1986: -1.3 (-1.0c)
1982: -1.1 (-0.2c)See, don't get too scared folks! Hell, even 1981-82, 1995-96 and 2010-11 are missing from here, night!
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Noob question here but why does it matter if the NH is blocked/not blocked this early in mid-october? We wont get any real cold for weeks anyway?
Most pertinently, the OPI is largely based around Arctic pressure patterns (in October) and there is a distinct correlation between OPI (October patterns) and the Winter Arctic Oscillation. A blocked Arctic, if in the right places, in October, often leads to a more blocked Arctic come Winter itself.
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I thought the panicking was meant to be for Winter! It's the 2nd lowest OPI in 38 years of recording, and potentially the worst run we've seen a while; I'm sure we'll see it sub -2 sometime soon (not that it's particularly important to be so).
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Further noting upon Phil n Warks excellent post #25, here is the CET-OPI correlation:
And there's a very striking correlation in fact; of course there are a few discrepancies but near enough 0.9 correlation w/ the CET.
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The most pertinent point yet.
After having a discussion on twitter last night I went back and looked at the previious OPI scores. And to me it looks like that the scores are the daily values ( go back and look at the daily scores) rather than the cumulative score with the addition of the average T+240 GFS score factored in. So the OPI indicated is the score today (yesterday now -1.13 ) rather than the cumulative score that perhaps Riccardo had led us to believe ( - this could be lost in translation).
However, all is not lost as I suspect that the next 10 days we will be near an average score. After that we may get a more positive daily OPI value as the AAM is set to rise and this will lead to a more pronounced polar jet stream. Perhaps not a bad thing to temper winter expectations at this point..... but I am likely to suggest a negative AO winter, unless there is a significant change in pre-winter conditions for the worse in the next 6 weeks.
By that reckoning, it's currently on around -1.8; and is expected to slowly rise.
For reference (thanks to BFTV), winter OPI's between -1 and -2 are 76/77, 78/79, 82/83, 84/85, 85/86, 86/87, 12/13; so it wouldn't be a bad point to be at one bit (of course it's one part of the jigsaw as Tamara, Chiono, SM etc allude to above).
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OCTOBER PATTERN INDEX (OPI) MONITORING WINTER SEASON 2014-2015
in Spring Weather Discussion
Posted
Certainly looking cold...
When using uniform scales, to try and see how each compares, this is what comes out:
(using 500mb GPH from -160mb to 160mb anomaly, 850mb temp from -4c to 4c anomaly)
December
Slightly cooler with rather insignificant anomalies, very much in line with the reduced OPI-Dec CET correlation, though stratospheric changes in November as pointed out by Chiono and many more could be integral to seeing which way it tips (seems like either average or thereabouts, to pretty cold).
January
Much more marked, again various other factors will probably temper or accentuate this, but the +ve GPH much stronger to the north-west, with Scandinavia in particular much colder. Showing a -NAO pattern more conductive to longer lasting cold.
February
Far away, we can dream though...