Gavin P
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Posts posted by Gavin P
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Last winter and the winter before came in just below average overall. The last two winters haven't been cold, only the individual months.
The winter of 2009/2010 was the coldest winter since 1979 (and in Scotland it was the coldest winter since 1963)
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The news from the US scientists is very concerning, though I believe the Russians were warning this was going to happen 20 years ago, so it shouldn't come as that big a surprise.
Nevertheless, if these scientists are right and the solar cycle is going to switch off for a few decades, we could be in for a very chilly time of it - Even assuming we don't plumb the depths of the LIA thanks to the warming AGW has given us, that could still leave us potentially facing a Victorian type climate, which would be pretty devastating to our modern way of life.
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A subtle dig from weatheronline?
"Summer 2011 perhaps not one shaping up to be one which many of us would have wished for and not what some had earlier lead us to expect?"
http://www.weatheronline.co.uk/cgi-app/reports?LANG=en&MENU=205&FILE=tma&DAY=20110611
Their long-term forecast is all doom and gloom, but that always seems to be the case.
I think they mean "what we had earlier been lead to expect" by the weather - I.E. a reference to the summery April.
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Well it appears the wise and wonderful Mr Hudson puts a lot more certainty into forecasts a week ahead than I do...will see if his WEEKLY forecast prevails shall we?
I find it absolutely staggering a fellow forecaster would stick the knife so deep into another!!!! Utterly gobsmacked!
I don't think Paul Hudson has really said aything *that* outrageous. Piers gets far more stick when his LRF's go down the tubes.
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"Can someone please clarify that it is now the norm to ammend LRFs?
Anyone looking at last winter's threads would notice a winter LRF, issued 20th Nov by crewecold:
http://forum.netweat...lds-winter-lrf/
As far as I can discover there was no ammendment to this LRF at any stage, it stood or fell in its entirity.
Indeed, and what is particularly pertinent, is Post #8, by a certain Mr J Holmes:
Posted 17 November 2010 - 08:43
well explained and a lot of work gone into it-result known 1 March!
Now maybe I'm a bit slow here, but that suggests to me that there won't be any changes to that LRF and it will be judged on its merits, at the END of the forecast period, over three months later.
In fact, no virtues of humilty and adaptability being lauded on this one.
Obviously, I still haven't "got it", but I'm sure it won't be long until the inconsistent judgements applied to this and the summer "LRF" will be explained to me."
Rob, I'll have a go at answering.
My answer would be that there has always been two strands of thought regarding LRF's.
1. You put you LRF out there and leave it to be judged at the end of the season, be it good or bad.
2. You put your LRF out there, see how things develop over time and then amend it as the facts develop - More of a rolling LRF if you like.
Some people don't see the point of allowing an LRF to stand if when its clearly hopelessly wrong. The Met Office always took this view. As did Ian Brown, Metcheck and Netweather.
Others think that changing an LRF as you go along defeats the object of doing an LRF in the first place. TheWeatherOutlook have always taken that view. As has Joe B'astardi and as did someone called Tom Presutti who was a well known long ranger back in the day.
I don't say theres a right or wrong answer to this. Ultimately its down to the preference of the forecaster.
My own preference is for putting your forecast out there and letting it stand, because its easier to verify correct and incorrect forecasts that way. If your constantly doing updates it can be hard to track down what the original forecast actually was - Though that won't be a problem in the case of Netweathers summer forecast I don't think.
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Which summer forecast are we discussing now? The original forecast or the revised one?
I ask because Paul Hudson has blogged about the prospect of a June wash-out and within the article he says this;
"We all remember the blaze of headlines at the end of May that this summer was likely to be as hot and sunny as the summer of 1976 - arguably the best and most memorable summer of the 20th century - leaving expectations across the country sky high that at long last we might be in for a barbeque summer.
These headlines came from a detailed forecast from private weather company Netweather.
They said only last month that 'Within the summer, we expect the core of the hot and settled weather to occur during June and July, particularly June which we think will be very pleasant with high pressure in charge across much of western Europe and the UK.'
Rarely has a long range forecast gone so spectacularly wrong, so quickly.
The Met Office is still haunted by their now infamous 'barbecue summer' forecast of 2009.
Netweather will be hoping that July and August shows a rapid and sharp improvement - or more likely that their 'shades of 1976' forecast is quietly forgotten."
http://www.bbc.co.uk/blogs/paulhudson/2011/06/flaming-june-could-end-up-a-wa.shtml
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August 97 is well beaten by August 1995.
August 1995 is the ultimate summer month as it is the driest, warmest and sunniest August on record. It will take something to beat August 1995. July 2006 came close but it lost out preciptation wise.
August 1995 was an outstanding month.
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I think the big mistake for Netweather and Glacier Point was using 1976 to compare to the expected conditions this summer. 1976 is The Daddy of summers. It would be like using the 1963 analogue in a winter forecast.
It can only ever really end in disappointment. -
The models today seem to be moving away from that extensive and prolonged greenland blocking we've been seeing predicted in recent days.
It *might* soon be game on for the Netweather summer forecast?
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Hi,
I am wondering why a Greenland High is such bad news for good weather in the summer months in the UK? Can anyone explain?
Basically its part of natures balancing act. The Greenland High deflects the jet stream south and with the jet stream often comes low pressure. Of course the jet stream in summer is usually quite sluggish, so we often spend an extended period stuck under a cool trough - In summer weeks or even months can go by without the pattern really changing.
If this verifys;
http://www.wzkarten3.de/pics/Recm2161.gif
I would say the minimum we're looking at to break out of it would be two weeks.
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Ah thanks for that, interesting.
I notice 1995 had a ridge in the Atlantic in the 1st half of June though looking at the archives it didn't seem to have a Greenland high, but who knows what that will mean if anything.
On a different note the forecast for here doesn't look too shabby over the next 5 days.
Yeah, 1995 had a very dull and cool spell in the first half of June with a northerly wind resulting from an Atlantic ridge. Pressure remained relatively low throughout over Greenland though.
However, it does highlight that June, particularly early June, can be very differant to the overall summer pattern. Late June and early July will be the critical period for the Netweather forecast, I feel.
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Just a note of caution re CFS
If you look at it on a daily basis you will notice that its predictions be it for 1 month or 6 months will vary almost as much as the GFS runs 4x daily.
It obviously can be used but it needs a lot of care when using it.
No single forecast tool is of any use on its own. That is true for short day to day forecasting or for longer work.
An understanding, and a deep one at that, for LRF work such as GP (Stewart) is certainly needed to produce any meaningful forecast. That goes for the 6-30 day Met O output or for the longer lrf work such as some web sites including our own at Net Weather produce.
Commenting on the output, much as I can understand the desire to do so, before the forecast has really got running, be that the 6-30 day or the summer prediction by any site, is a bit pointless. Quite often as well the forecasts are taken out of context, or little bits that suit the poster are used to try and illustrate, usually its failure, less often its success.
end of jh sermon
John, the temperature and rainfall anomalies can change quite regularly, but the CFS pressure anomalies are very good up to three months out, I've found. For the past three winters CFS has had the basic pressure set up quite well honed by September/October and has generally kept with the trend throughout.
On these forecast pressure anomalies;
http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images3/glbz700Mon.gif
http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images3/glbz200Mon.gif
I can't see anything really that would suggest a summer out of the ordinary?
Now I'm not saying the "shades of 76" forecast won't come off, but at this stage it does look to be getting off to a rather shaky start, IMO.
As ever time will tell.
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Links should be working OK now.
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CFS is predicting a very wet summer across much of France and Spain;
http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images3/euPrecMon.gif
If this is correct, it will have a big impact on Netweather prediction of a "summer with shades of 76" for two reasons;
1. Without dry, baked ground across the Continent it will limit the potential for heat to build and build and build over the landmass like it did in 2003 for instance.
2. It suggests pressure will be low across the continent, so any southerlies we do get will likely quickly become unstable with the result being a "three hot days and a thunderstorm" type scenario.
The pressure anomaly looks very weak across N/W and the Atlantic throughout the summer;
http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images3/glbz700Mon.gif
No suggestion of a blocking high within the vicinity.
Added to this we have the models running with a large Greenland High and a trough over N/W Europe well into June
And at this stage Netweathers LRF is looking increasingly unlikely, I'm afraid.
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Revising down to 14.9 thanks.
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Hadley is on 12.6C today (May 1 - 29) which is a 0.1C increase on yesterday but actually represents no change over the last 7 days. Today looks average and tomorrow after a chilly night tonight should see a 0.1C reduction. So given the usual 0.2C downwards adjustment it looks like 12.3C is a good bet as a finishing mark which will just ensure a record warm spring.
I also have a feeling the downward adjustment might be slightly bigger than normal this month. That Spring record isn't in the bag yet.
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I can't remember much about the 89/90 winter. The only thing that really stands out is the Burns Day storm.
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Historically, weak La Nina is by far the best ENSO state for cold winter scenarios.
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The problem I think we have this June and through the summer generally, is that low pressure will continue to run to the north of Scotland and into Scandinavia. This will have the effect of regularly pulling high pressure back into the Atlantic and keeping the air from an Atlantic based source. Even so, there will be some limited hot spells and with pressure high I think we're in for another very dry month away from northern Scotland.
Putting it all together I'm going for a CET of 15.4
A warm month, but not a classic June, and that probably goes for summer, too
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The problem I think we have this June and through the summer generally, is that low pressure will continue to run to the north of Scotland and into Scandinavia. This will have the effect of regularly pulling high pressure back into the Atlantic and keeping the air from an Atlantic based source. Even so, there will be some limited hot spells and with pressure high I think we're in for another very dry month away from northern Scotland.
Putting it all together I'm going for a CET of 15.4
A warm month, but not a classic June, and that probably goes for summer, too.
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I never knew we had a drought that lasted that long. Just shows you learn something new everyday. I do remember some hot dry weather in the july of that summer.
Well, not every month from 1988 to 1992 was dry. There were some isolated wet months like April 1989 and June 1990 and as we're discussing June 1991, but overall November 1988 to June 1992 was an incredibly dry period with the majority of months coming in with below average rainfall.
Then from July 1992 to February 1995 we had a much wetter period with a lot of above average rainfall months.
April 1995 to April 1997 had another extended dry period, including the incredibly dry and hot summer of 1995.
May 1997 to December 2000 saw a very wet period, including the incredibly wet autumn of 2000.
It amazing how rainfall evens itself out. This actually has some relevence on the current situation, because since about October 2008 we've had a lot of drier than average months. As we can see these periods usually last 2-3 years, so we've probably not got much longer to go before we get a switch into a much wetter period.
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There is a season that comes between summer and winter and its called autumn. Its sadly neglected and last autumn was fairly interesting with some interesting weather.
CFS seems to be indicating a very wet autumn (well September and October) at the moment.
Would be a change. We've not had a wet September since 2000 and we've not had a wet October since 2004.
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You have bypassed dinner and cut to the chase? What about autumn, I can imagine an autumn thread, but winter thread? I would wait till around Mid summer(last years was made around then), like the spring thread was made at the start of the year, 3 months beforehand.
Anyway early indications for AUTUMN on cfs show:
http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images3/glbz700Mon.gif
September Unsettled, with some blocking to the north and low pressure around the uk and the south, could be cool at times, but also mild at times looking at those anomalies.
October, dry and cold at times, relatively cool/cold by the looks of it.
November- Neutral atm, but the indications a few days ago showed a similar anomaly to september, with the blocking a bit more intense and the blue anomalies stretching over the azores, maybe another cold november.
I think an unsettled and wild autumn could be on the card though, with us gradually sliding into the cold and an early winter.
My interpretation of those CFS anomolies would be;
September - Very wet with near stationary trough over or slightly to the west of the UK. Temperatures near normal or perhaps rather warm.
October - Cold and probably very wet with greenland blocking and a southerly tracking jet stream.
November - Who knows?
As far as my own opinion on winter 2011/2012 goes, much to early to say. Though it would be quite amazing to have a fourth colder than average winter in a row.
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Paul Hudson looks at a number of summer LRF's, including Netweather;
http://www.bbc.co.uk/blogs/paulhudson/2011/05/is-summer-2011-set-to-be-a-sco.shtml
It can only ever really end in disappointment.
Mini Ice Age On The Way?
in Spring Weather Discussion
Posted · Edited by Gavin P
However, it is suspected that the UK and Europe is especially prone to weakening of the solar cycle because it appears to cause the jet stream to move south. The reasons for this are not understood, but there is more than circumstantial evidence to suggest that when the sun is on its minimum part of the cycle blocking episodes become more frequent.
The evidence of effects is much weaker for other parts of the world. If these scientists are correct one of the most likely outcomes would be cooling for the UK and Europe and also more prolonged periods of extreme weather caused by buckled jet streams - So for instance a record cold month, followed quite soon after by a record warm month, followed quite soon after by a record wet month, followed quite soon after by a very cold winter, etc.... would not be uncommon, rather than extended periods of temperate normality, woth only the occasional extreme month thrown in here and there. Almost similar to the weather patterns we've been seeing since 2007? :blush: