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A Winter's Tale

The Seasonal Forecast Thread

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This Piers Corbyn discussion should be over in the Piers Corbyn thread. This is a thread to discuss seasonal forecasts from NW members.

I don't think that attitudes towards Piers Corbyn should be allowed to destroy interest in more accurate forecasting programs.

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I am relatively pleased with the outcome of the spring forecast, can certainly see some aspects that would benefit from further study, but the basic idea (increasing northerly blocking and cool/wet periods) seems to be holding together. The spring forecast mentioned some indications in the research that June would turn much warmer and the summer could be a warm one.

This is still my outlook. I will post a detailed forecast if we have a summer forecast thread, but basically, the numerical output that I use from research in-house is showing a relatively warm summer although with some slightly below normal days at times, the trend is about 1 C deg above the baseline which would be similar to 1961-90 normals, so more like 0.5 C above recent 1981-2010 normals. Actually June and July have not really warmed that much from the olden days, especially June. In any case, my forecast calls for some bursts of very warm or even hot weather in early to mid June, and on several other occasions during the three summer months, and an extension of summer into September which may (from the output) be even warmer relative to normal at least, if not in absolute terms. I would expect this pattern to mean some heat waves for the south with readings into the mid-30s possible. The recent summer that looks most similar to the output would be 2005. I think there is even some chance of a notable heat wave but will go conservative and say that the summer may end up between average and above-normal in both temperature and sunshine. For rainfall, I am expecting a rather indistinct pattern because some aspects of the fading blocking pattern may remain imprinted, so there may not be a huge variation from normal but no really clear regional signals, from the guidance of my index values. Intuitively, I would expect the modified drought to reappear later in the season and possibly a wetter trend further north.

I extended the output through autumn and winter -- that looks mainly above normal in temperature also.

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1. RJS

This forecast is based on the same numerical index analysis from daily and monthly CET as well as a general overview of the hemispheric forcing currently being displayed by various global signals such as SST anomalies.

The general spring forecast calls for a wetter trend for much of the southern U.K. to end or at least modify the dry conditions we find at present. Temperatures will be generally near normal on average with some rather chilly spells after a warm start. As "spring" is defined as March, April and May, the prospect for very warm weather in early June would qualify for summer although many will see that as a spring to summer transition.

March will start out relatively mild and begin to turn more unsettled, then a rather large-scale pattern change around 10th to 15th can be expected with northerly followed by some northeasterly flow and a more wintry feel, with the CET struggling to hold its early positive anomalies and settling into the 5.5 to 6.0 range. There will probably be one snowfall event in this period as well as more frequent hill snows. When it does warm up somewhat, it will probably become quite damp, but rainfall amounts will likely be around normal with a tendency to dry conditions in parts of Scotland.

3

April will probably follow a similar trend with a warmer week to ten days to start the month (around Easter) then back into a cooler, unsettled pattern with frequent northwest to northeast winds and the onset of a heavier rainfall regime in the south as low pressure often takes up long residence near the Channel or in northern France. The CET will be held in the 7.0 to 7.5 range and there could be late snow or sleet making the season seem particularly backward compared to last April.

8

May could develop into a very wet month as the cool, unsettled pattern intensifies; there may be a large omega-blocking pattern over the central Atlantic into Scandinavia with low pressure trapped over western Europe. This may give parts of Scotland and Northern Ireland a dry month compared to southern England which could be exceptionally wet. The CET will be depressed by all the cloud to a value around 10.5 to 11.0. Some northerly gales may develop at times later in the month as part of the gradual breakdown of the blocking and the month may end with more settled weather. A warm spell or heat wave may follow in early June.

9 = 20

2. Stewfox

March

Mixed bag with PM incursions and less blocking. Mobile Atlantic, rainfall likely to be above average for most regions and temps marginally below.

3

April

The long over due cold April arrives with cold Easter (not snowy) CET 1.7c below the average.

8

May

Rainfall above average , sunshine amounts below. CET around average but warm month end.

6 = 17

3.

CSS Spring Forecast 2012

Overview

With Winter being mainly Atlantic dominated with a persistent Azores High, I believe that a very interesting Spring is on the cards. I believe that March will start of Atlantic Dominated but I do believe that we will see it become quieter - I believe that his could result in a mixture of cold and warm spells for March and April with plenty of sunshine and increasing the risk of drought although showers may still be possible in the NW. I believe, usually, we'd atleast expect a decent warm spell between Mid April and Mid June so I'm confident that May will see periods of warmth, sunshine and potential thundery breakdowns but it's a question of whether May would continue being generally warm and dry or will the Atlantic return bring wet conditions but with a possibility for cool, showery conditions. I believe that this Spring will be pivotal in the summer that we get - particulary April and May so a warm theme of May well carry on into June but eventually the Atlantic may return leading to poor periods in summer.

MARCH

March is set to start of a wet, windy, unsettled and mild note with some sunny, showery spells between fronts. However as we progress through the month, I expect there to be an increase in northerly outbreaks and potential easterlies as we see height rises return either over Iceland or Greenland. This would mean that the jet stream will move south for periods resulting in spells that include northerlies with snow showers to the north but generally sunny conditions, however the Atlantic will intervene at times. Towards the final third of the month, I expect to see some warmer days mixed in with the northerlies, fronts and a continued sunny flavour.

3

APRIL

I expect April to start on a showery note with westerly winds, these generally cool but there may be the odd warmer day thrown in. However, eventually I see winds turning to more of a northerly setting up and cool-cold early-middle part of the month with a continued risk of snow to the north. Following this, I expect a return to fronts from the west breaking up long, periods of generally sunny conditions with a mixture of settled to showery, cool to warm. During the final part of the month, I expect temperatures to be on rise and more undisturbed periods of sunshine.

6

MAY

I expect the very early stages of May to see sunny, but pleasant to warm temperatures with the odd cool night as the April shower regime begins to fade out. As we progress, we'll see an increase in temperatures but there may be the odd front to break up seperate periods of sunshine and warmth. Towards the middle of the month, I expect the Atlantic to return and subsequently there may initially be some thundery conditions. Following this we may see a period with low pressure systems crossing over the UK bringing rain, but clearing quickly to introduce cooler but sunny conditions with the threat of wintryness on the northern hills. There may also be the odd day thrown in. This shouldn't last too long as to finish off the month, I expect a trend for a return to sunnier conditions with warmth but these periods may be regular - but short lived.

4 = 13

4. Isolated Frost

Synoptically, I was pleased with December, January was awful and I am very happy with my February forecast. Mixed, GP's and lomondsnowstorm's ones are my favourites.

Spring- a lovely but difficult season to predict, my early thoughts are for a lopsided March- mild for the first half generally, increasing cooling and more blocked towards the north as we end the month.

2

This continues into April to continue the cold and dry theme- before turning gradually wetter as the weak jet erodes the progressive block.

4

May then becomes gradually warmer, with high pressure increasingly dominating as the jet fades, and some hot spells creep into the pattern as we move into summer.

2 = 8

5. ElectricSnowStorm's Spring Forecast:

My Spring LRF 2012 Preview:

Early spring-March

Mid-April

Late-May

  • March(early) - Wet and Cold with Low pressure systems moving across from the Atlantic bringing with them snowfall at times, coldest in the East and EA/SE, some frosty/foggy spells as ridges of high pressure replace the weather systems, wintry for many, possibly warming up in the South late March with high pressure quite strong from the s/sw, cold in the North.
3
  • April(lmid) - Warmth arriving in the South early month with drier then average, cool/mild in the North with more wetter conditions especially the northwest. mid to the end of this month Southern areas seeing high pressure with warm or very warm and dry conditions, depending on how far North the high pressure moves would mean how far North the nice weather gets and how much the wetter weather gets pushed away North, can't say at this stage how far would ridge North, but its looking dry and warm for the South.
2
  • May(late) - Very warm and Mostly Dry month with the Azores high in place, although storms/showers could occur as i expect a warm moist flow from the south at times as deep lows move near by in the Atlantic-and when this situation does develop then flash local storms could occur, although most lows pushing across the far North some might move up from the south as thundery lows, at this stage it is really not possible to predict such set ups, but on a larger scale i see a dry month in terms of widespread rainfall, also i expect the Jetstream pattern to be much more different then last spring(more details in the forecast)
2 = 7
  • Overall - I am expecting a cold and wintry start to spring, with a drier and warmer 2nd half in the South and more cooler and wetter in the North, it does depend on how far North the high pressure can make it to how warm and dry the North becomes rather then cool and at times wet.
  • Spring 2012:
  • Early:Cold wintry start North to South
  • Mid-Late: warm&dry South/cool&wet North, if high from south ridges north then warmer and dryier in the north, Jet stream pattern would result in changes.
  • Colder then Average March overall
  • Drier then Average April in the South
ESS

Still a bit of May to go but it seems like RJS again has impressed with his seasonal forecast for Spring 2012. An improvement of 2 points from the winter forecast and this is with a March that scored 3. But April was generally very accurate despite the forecast mentioning a warmer first 10 days - perhaps a 10 day late, end of March heatwave. May, scored very well with a cool and wet month being a very accurate generalisation and Scotland and Northern Ireland being somewhat drier than further south seeming to be accurate too. And perhaps a warmer end to May could be on the cards, a very accurate forecast.

Stewfox's first forecast was very good with a score of 17 points. An inaccurate March but April and May were generally very accurate. Well done!

For my forecast, an improvement of 3 points from my winter forecast. March caught me out a bit. The start of the month in my forecast is generally accurate but most of the rest is very innacurate. I did mention some warmer days towards the end, but not good enough to imrpove the rest of that forecast. April is one of my most accurate months so far, generally pretty accurate with mentioning cool, showery and northerlies. The warmer end to the month prevented my forecast getting a higher score.

Isolated Frost scored 8 points, 2 lower than the winter forecast. Like myself and RJS, IF got caught out with March, perhaps if cool and mild swapped places then it would score more points. April is more accurate with cool and wetter weather mentioned but dry brought April down greatly. A warm and settled May is so far the opposite of what we've exprerienced this year.

Electric Snow Storm Scored 7 points - the same as winter - and got caught out by all three Spring months.

Well done to everyone who attempted a forecast. Big Congratulations to Roger J. Smith who has the most accurate Spring forecast, following from GP with the most accurate winter forecast. I hope to see more members attempting the summer forecast and it will be interesting to see who comes out on top in the coming seasons and the progress of everyone taking part.

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On the validation, I would say you've got a reasonably fair set of numbers and I don't question them in particular, but people will feel that their forecasts are good in some cases that lack details because what they do say is generally right -- and this underscores the problem that a real test of these forecasts requires the numerical approach where actual values are predicted and tested. I make some attempt to provide these and it helps me to assess where I need to improve, the words are also important, but if you said something like "May will be a real shocker with a CET near 7" then you would get totally shelled in a numerical validation, if perhaps you just hadn't checked the numbers to see what was actually cold in May. But total objectivity is difficult when forecasts are made in the open, a true test would require a blind forecast (no knowledge of competing values). There again, I am not suggesting any cross-contamination, but considering where we were in late February and early March, it is surprising as well as encouraging that all these forecasts mentioned a blocking and cooling and wetter trend to follow. I suppose it was the only thing that could follow if you threw out persistence.

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Re the above, his statements about Netweather are unjustified. In the seasonal forecasts above, the entrants were fairly consistent in predicting a below normal April and May (from times before Piers Corbyn's forecast). On the other hand, the values mentioned were less extreme, and more accurate. Also, in the monthly CET contest, the median of 68 entrants was 10.6 C which now looks a lot closer to reality than "coldest in a hundred years." I agree that the meteorological authorities should look into alternative forms of long-range forecasting. My phone number can be obtained through the personal message system (I'm not kidding, if you're going to pay, might as well get a good one).

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Marking forecasts is always a very difficult thing to do to the satisfaction of everyone.

The first MUST is that any forecast has to be assessed by someone, company, group, department etc, that has not prepared the forecast.

Secondly the rules by which it is to be marked MUST be agreed BEFORE the forecast is prepared.

Obviously the forecast has to be objectively judged and without any comment about anyone else and what/how etc they have produced a forecast.

Just how many individuals, groups, companies etc would agree to that I have no idea. But until that is done then we will get the kind of comment (I really am trying not to make unfair comments about some folk) that we read on this forum and elsewhere.

From the point of view of our own Net Weather then the current system prepared by ASWT seems as good as any other. There have been no howls of protest from individuals just mild comments suggesting they be marked higher in places?

How about, ASWT, you do your best with the person who causes more hot air than most on this forum-no names mentioned, compare it as fairly as you can, using your current method, with any other prediction?

Worth a try in my view if you would be prepared to give it a go?

Edited by johnholmes

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Marking forecasts is always a very difficult thing to do to the satisfaction of everyone.

The first MUST is that any forecast has to be assessed by someone, company, group, department etc, that has not prepared the forecast.

Secondly the rules by which it is to be marked MUST be agreed BEFORE the forecast is prepared.

Obviously the forecast has to be objectively judged and without any comment about anyone else and what/how etc they have produced a forecast.

Just how many individuals, groups, companies etc would agree to that I have no idea. But until that is done then we will get the kind of comment (I really am trying not to make unfair comments about some folk) that we read on this forum and elsewhere.

From the point of view of our own Net Weather then the current system prepared by ASWT seems as good as any other. There have been no howls of protest from individuals just mild comments suggesting they be marked higher in places?

How about, ASWT, you do your best with the person who causes more hot air than most on this forum-no names mentioned, compare it as fairly as you can, using your current method, with any other prediction?

Worth a try in my view if you would be prepared to give it a go?

Hi JH!

I'm not that experienced in analysing forecasts and I only mark forecasts as part of my own judgement and as no one else has used their own to time to sit down, read some forecasts, mark it and so on. I'll quite be quite happy is someone with more experience with LRFs and weather and climate in general could use their time to mark forecasts. With your knowledge and experience JH, I would imagine you'd be very good at marking LRFs.

The Long Range Forecast Thread is for some members just wanting to test themselves at LRF's for fun or some more experienced members wanting to experiment and challenged themselves seriously. Create your forecast, and see how accurate it turns out at the end, hopefully, the members participating would be able to judge that collectively rather than just myself.

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JH, if you're saying what I think you're saying, I would give the said forecast for May a 7 in the scale ASWT uses. Said person went a bit too cold to go as high as 8 or 9 and over-emphasized wintry precip. But it was a relatively close result by standards of said person in particular. I don't know what said person predicted for March or for April so a seasonal comparison would need access to those forecasts as well.

Maybe you're not saying that, I had a bit of trouble peering into your crystal ball.

But as to the assessments made by ASWT, I haven't looked at all of them with equal scrutiny (including all the winter seasonals), but I have come to accept that they will be reasonably close given all these uncertainties about actual numbers that don't appear in most of the forecasts. JH is right in saying that the field needs a more formal validation system that everyone (or mostly everyone) accepts and that will require a numerical basis for agreed locations. Otherwise it is very much apples and oranges, as we sometimes see in the CET thread where one person says the month seems cold and another says it seems warm, possibly it has been both at their two different locations but the CET is a known quantity that everyone has to play "by the numbers" so that removes any subjective element.

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okay I can understand why you do not want to do it. As for me seasonal forecasts are way beyond my remit either for trying them out or, with fairly limited time, doing the marking. Anyone else interested in becoming the unofficial lrf checker for Net wx?

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Summer forecast 2012: Heatwaves and thunderstorms.

Over the 3 summer months i'm expecting above normal frequency of southeasterlys across southern UK, and on a whole across all areas we could see above average thundery activity, this more higher across southern and central zones, more likely to see imported thunderstorms and a higher risk of those rare night storms.

I expect to see prolonged heatwaves and thundery muggy periods, there would be prolonged periods of hot weather, some of the hottests days through late June and July, this heat becoming widespread at times and sending very warm air flows right up into the far north, southern and central areas and those prone to the heat(hot spots)recieving the highest temperatures, with August being lowest confidence to forecast.

June and July -

For rainfall during the first 2 months i see this being lower than average widespread rain with the rain coming from convective activity in the way of downpours and storms, some active fronts affecting western areas where i expect more thundery frontal rain to be present then elsewhere during June and July, also these being slow moving at times, across the drought zones(some may have changed drought status)there is a higher risk of less widespread rainfall but a higher risk of downpours and storms locally causing flooding, temperatures would be generally above average from the more prolonger warmer and hotter weather.

August - Low confidence at this stage but i see a risk of widespread wetter weather and cooler spells with more low pressures from the Atlantic, more likely later in the month.

Generally most areas should get a nice and warm summer with some thundery action at times and also some really bright long sunny periods of weather.

ESS

Edited by ElectricSnowStorm

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ASWT'S SUMMER FORECAST 2012


The Spring of 2012 was certainly an interesting and notable one. March was one of the warmest on record with settled and very warm conditions following a cool, changeable and unsettled first half. April, was a very different story as High Pressure sat over Greenland resulting in cool winds from the north. A very unsettled month and a cool one with frosts and wintry weather. This unsettled and cold regime continued into the first half of May, however, recently we've seen High Pressure move into favourable locations for sunny and warm conditions to reach the UK. This looks set to see the rest of May out and may last into the first part of June. But what I see happening is a very changeable and transistionary month in June. High pressure may move from the UK and Europe towards the North Atlantic/Greenland which may see a brief return to cold and unsettled weather. However, I expect intervening spells of both warm, settled and at times thundery weather and cool, wet and unsettled conditions. I expect this theme of changes between warm, dry to cool, wet conditions to continue into July but I also expect longer lasting and more prominent periods of summery conditions. I expect August to also be an interesting month, a volitile situation with unsettled conditions prevailing but summer conditions also abundant inbetween rainfall.

JUNE


I expect June to start of on a mainly sunny and warm note with high pressure in control. However, not too long into the month, I expect High Pressure to move over towards Greenland allowing for unsettled conditions to intervene. Expect a good share of rainfall and cool temperatures but also expect some spells of sunshine. I believe that after a cooler and wetter period, warmer and drier SEly winds should follow. This would see the southern parts of the UK experiencing the best of the summer warmth although everywhere should enjoy warm temperatures and sunshine. The far NW may see some rain and cloud at times. Some storms could be present at times in the warm, easterly flow. However, periods of settled conditions won't be wall-to-wall with low pressure intervening - however, this can still bring spells of sunshine - albeit short-lived.

JULY


Somewhat unsettled conditions with a mixture of sunshine/showery and fronts followed by sunshine may last into the first part of July. However, I expect July to be the month with the best of the warmth and sunshine with the longest and most potent heatwaves. Winds from the east and south will be present and will bring classic summer weather to the UK. Not always scorching hot but warm enough to feel properly like summer. However, these periods of summer weather will yet again be followed by periods with cooler temperatures, more rainfall and less sunshine but pleasant summer weather will be present in a somewhat restricted way.

AUGUST


August is a month where progressively more unsettled and changeable conditions. Atlantic depressions bringing heavy rain, periods of cool-showery weather from the NW and cool, windy days with sunny intervals will bring a different feel to the weather of this summer. Warm, sunny and pleasant conditions will be regular behind depressions but these will be short-lived, less hot and less widespread. So a good deal of sunshine is likely in August but mixed with a good deal of wetter and windy conditions. A volitile situation is possible into the latter part of the month with some progressively more autumnal conditions but with some late summer warmth and sunshine present and the possibility of Spannish Plumes.
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I struggle with summer forecasts. Perhaps we will see more lengthy dry sunny warm spells this summer cancelling out the wetter cooler periods, a bit like 2005 the last summer which saw lengthy very warm sunny spells but also some pronounced rainy thundery periods most notably in July.

Who knows.. I just hope it isn't as wet as the last five, with endless long periods of often cloudy windy showery/wet weather and we don't end up in sods law territory again where a poor August is followed by late summer fayre in September and October when frankly it is too late, however, much people say ahhh an indian summer!! what happened last year was a kick in the teeth it has to be said, a season bookended with the best summery conditions in April and late sept/early october - terrible!

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Not at all trying to distract from some things that have required a lot effort but a point from me would be how can you judge may (on the 18th ) when we were only just half way through it ?

For example if's forecast for may might turn out far better than the 2 if things pan out as per the latest models and Rogers far lower than the 8.

Gl all

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I wouldn't say far lower, the month is almost over and there is a clear indication of a regime change from cool/wet to warm/dry in the forecast for the end of May into June. Looking at the numerical output for the forecast, I would say this warm spell has come on about five days ahead of the forecast output. So that's not too bad from three months out. I've always said that this approach will perform at about 65% accuracy relative to normal giving an improvement over random. This past season has done a little better than that and so for that matter did the winter forecast.

Since summer forecasts are appearing here, and I only gave a sketchy one, this is the actual forecast. I'm giving this in a format that I think would be good for all forecasts to provide a more objective scoring system.

JUNE ... Mainly warm and dry, especially first half of month. Temperatures 1.5 to 2.0 above normal, CET 15.9. Rainfall around 70% southeast to 90% northern half UK, sunshine 10-20 per cent above normal.

JULY ... Near normal conditions first half then back to warm and dry, some heat waves. Temperatures 1.0 to 1.5 above normal, CET 17.3. Rainfall around 100% of normal but with wide variations locally, some severe storms likely first half, dry trend second half. Sunshine 10-20 per cent above normal mainly due to frequent sunny days second half.

AUGUST ... Heat wave conditions likely at times, temperatures 1.5 to 2.5 above normal, CET 18.2. Rainfall around 50% of normal, isolated storms but many places going into drought conditions, sunshine 20-30 per cent above normal.

Max temps for the summer could be as high as 37-39 C and there may be comparisons to 1990 or even 2003.

Comment ... while this may sound like non-stop hot weather, there could be one or two spells of cool weather lasting a few days between the warm spells. The word "reload" may become familiar in the model thread.

P.S. -- I may be totally kidding, imitators could discover themselves out on a limb when I change this later. Or will I?

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yes I like your format Roger-as to the content I suspect your 'real' forecast may be a touch different?

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No summer forecast yet from Netweather only seven days left???

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Okay, I'll end the suspense, that is my forecast. So now you're doomed to three months of low cloud, drizzle and chilly winds from the sea. Oh wait a minute, I'm not visiting, you'll be okay (1965, 1972, 1978, 1988, 2007 ... RS visits land of birth ... see a pattern there? And it was June 1972, aargh. ).

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I wouldn't say far lower, the month is almost over and there is a clear indication of a regime change from cool/wet to warm/dry in the forecast for the end of May into June. Looking at the numerical output for the forecast, I would say this warm spell has come on about five days ahead of the forecast output. So that's not too bad from three months out. I've always said that this approach will perform at about 65% accuracy relative to normal giving an improvement over random. This past season has done a little better than that and so for that matter did the winter forecast.

Since summer forecasts are appearing here, and I only gave a sketchy one, this is the actual forecast. I'm giving this in a format that I think would be good for all forecasts to provide a more objective scoring system.

JUNE ... Mainly warm and dry, especially first half of month. Temperatures 1.5 to 2.0 above normal, CET 15.9. Rainfall around 70% southeast to 90% northern half UK, sunshine 10-20 per cent above normal.

JULY ... Near normal conditions first half then back to warm and dry, some heat waves. Temperatures 1.0 to 1.5 above normal, CET 17.3. Rainfall around 100% of normal but with wide variations locally, some severe storms likely first half, dry trend second half. Sunshine 10-20 per cent above normal mainly due to frequent sunny days second half.

AUGUST ... Heat wave conditions likely at times, temperatures 1.5 to 2.5 above normal, CET 18.2. Rainfall around 50% of normal, isolated storms but many places going into drought conditions, sunshine 20-30 per cent above normal.

Max temps for the summer could be as high as 37-39 C and there may be comparisons to 1990 or even 2003.

Comment ... while this may sound like non-stop hot weather, there could be one or two spells of cool weather lasting a few days between the warm spells. The word "reload" may become familiar in the model thread.

P.S. -- I may be totally kidding, imitators could discover themselves out on a limb when I change this later. Or will I?

As jh says, your format and layout is very good. It would be good if forecast entries followed a similar format which would make comparisons a lot easier.

A general, bitesize description; numerical prediction of range of temperatures compared to average; CET prediction; rainfall percentage prediction plus description of general precip; sunshine percentage compared to average - sounds like a very good format to follow. I often find that I wobble off in my forecasts so perhaps I would be better off breaking it down into a similar format.

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I hope we will one day have meaningful validations and also movement towards funding and acceptance of valid approaches. Almost like a real science, you might say.

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Wow... I completely forgot that I put a forecast... but how about this for almost correct??

MAY 2012 - Summary - Unsettled May - Well above average rainfall, below average temperatures, very windy weather on exposed locations, ending on a high in the last week of May.

A very wet month in most places, with a top temperature of 23-27*C during the warmest parts in the last week of May. Low pressure very dominant, during the first week of May with a continuation of westerlies, with temperatures averaging very close to 8-13*C across most parts of the UK. Sunshine amounts are likely to be highly variable during these conditions. Unsettled conditions to prevail during the second week of may, with many places seeing above average rainfall and below average temperatures. During week 3 in may, temperature remaning below average with rainfall continuing to be well above the average. By week 4 high pressure builds over western and central northern parts of Europe, allowing the most unsettled conditions into Iberia. Temperatures recovering to average, sometimes above average in the Sunshine.

Edited by Robbie Garrett
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As jh says, your format and layout is very good. It would be good if forecast entries followed a similar format which would make comparisons a lot easier.

A general, bitesize description; numerical prediction of range of temperatures compared to average; CET prediction; rainfall percentage prediction plus description of general precip; sunshine percentage compared to average - sounds like a very good format to follow. I often find that I wobble off in my forecasts so perhaps I would be better off breaking it down into a similar format.

I think that is good thinking, i was going to post last night that there are two types of forecast appearing, one is what i do and that does not contain numerical information, and the other being the format type what RS/others do. What you are saying is something i will think about, i may come back with a re-edit of my forecast giving this extra info along side my text. Another thing thats on my mind here is that when a forecast has a synoptic description for a said period, and it turns out that the setup/synoptics are different but the same weather is presenting itself (high pressure placement different), then could this be pointed based on the weather type and the synoptics separately?

Maybe the points from the forecasts could be displayed in a graph?

Edited by ElectricSnowStorm
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Funnily enough May is now looking to come above average with below average rainfall here. A week ago I would have said no chance.

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My first attempt at a different format; 2nd and final version of summer forecast:

ASWT'S SUMMER FORECAST 2012

JUNE ... mostly warm and dry, with short unsettled interludes. Temperatures 0.5 to 1.5 above normal. CET 15.3C. Rainfall 55% south east to 75% north west, storms and occasional fronts providing most the rain for the SE, a mixture of fronts and showers providing rain from the NW during unsettled interludes. Sunshine 15-20% above normal.

JULY ... cool and wet periods likely at times with warm, dry conditions and some heatwaves likely too. Temperatures 0.5 to 1.0 above normal. CET 16.6C. Rainfall 60% south east to 85% north west, atlantic lows, showery and storms providing rainfall, driest towards the SE. Sunshine 5-15% above normal.

AUGUST ... changeable, mainly warm and dry start mixed with cool and wet blips, cooler and wetter end with some warm and dry periods. Temperatures 0.0 - 1.0 above normal. CET 16.3C. Rainfall 80% south east to 90% north west with atlantic and channel lows, showers and storms bringing rainfall. Sunshine 5-15% above normal.

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I wouldn't say far lower, the month is almost over and there is a clear indication of a regime change from cool/wet to warm/dry in the forecast for the end of May into June. Looking at the numerical output for the forecast, I would say this warm spell has come on about five days ahead of the forecast output. So that's not too bad from three months out. I've always said that this approach will perform at about 65% accuracy relative to normal giving an improvement over random. This past season has done a little better than that and so for that matter did the winter forecast.

Since summer forecasts are appearing here, and I only gave a sketchy one, this is the actual forecast. I'm giving this in a format that I think would be good for all forecasts to provide a more objective scoring system.

JUNE ... Mainly warm and dry, especially first half of month. Temperatures 1.5 to 2.0 above normal, CET 15.9. Rainfall around 70% southeast to 90% northern half UK, sunshine 10-20 per cent above normal.

JULY ... Near normal conditions first half then back to warm and dry, some heat waves. Temperatures 1.0 to 1.5 above normal, CET 17.3. Rainfall around 100% of normal but with wide variations locally, some severe storms likely first half, dry trend second half. Sunshine 10-20 per cent above normal mainly due to frequent sunny days second half.

AUGUST ... Heat wave conditions likely at times, temperatures 1.5 to 2.5 above normal, CET 18.2. Rainfall around 50% of normal, isolated storms but many places going into drought conditions, sunshine 20-30 per cent above normal.

Max temps for the summer could be as high as 37-39 C and there may be comparisons to 1990 or even 2003.

Comment ... while this may sound like non-stop hot weather, there could be one or two spells of cool weather lasting a few days between the warm spells. The word "reload" may become familiar in the model thread.

P.S. -- I may be totally kidding, imitators could discover themselves out on a limb when I change this later. Or will I?

Good read RJS - I always enjoy reading your forecasts and admire your methods (thought I dont understand them...) You have a high hit rate - in my opinion. However I think you have been out of the country a bit long!! Sometimes you rather overcook your winter estimated minimums and likewise your summer maximums. If anywhere in the UK hits 39 degrees I'll eat more than just my hat... and I dont think 37 is anywhere near a reality either. That sort of extreme just doesnt happen here - the ocean has too great an effect. I'm sure someone somewhere will pull out figures to prove that such extremes have happened once in a blue moon... but there is no way we will have temperatures like that widespread across the country. It is very unusual indeed for temperatures to break 30: instead anything in the 26 - 29 bracket here would be considered hot and 30 degrees rare.

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