The Seasonal Forecast Thread

[Roger J Smith]

"Some hope for improvement" the sequel.

 

Summer LRF seems to be on track in general terms, and leaning somewhat towards the "exceptional summer" although I'm happy enough with the positioning between warm and hot suggested in the actual wording.

 

Have rebooted the model to extend into autumn as reported on the autumn thread. August as already available from the research still looks warmer than average by 1-2 deg but I suspect that rainfall amounts will begin to return to more normal values towards the second half. This might imply that the peak of severe potential would be late July to early August when this more zonal (albeit high latitude jet stream) begins to replace the blocking.

 

By September I'm seeing evidence for a fast zonal flow pattern and temperatures closer to normal although the climatology of hot summers favours a warm September. The compromise might be something like a +1 anomaly overall with near normal rainfall and a fairly high probability of one windy event of tropical origins perhaps. The output shows a cold spell in early October that would likely be a northerly associated with a brief Greenland high regime, then a rather lengthy Indian summer period in later October and first half of November. Winter LRF will be announced no earlier than late September and possibly mid-October, considerable work required to update the current model output beyond mid-November.

[Alex]

My Summer Forecast 2013 By Alex: it's been a pretty cool Spring this year which has been very similar to Spring 2006. Will the summer follow a 2006 type? The answer is possibly! We have very different Synoptics to the last few years - interestingly this cool unsettled end to May has coincided with the last stratospheric warming and the warming out of the current nearby trough is likely soon - how soon leaves us is questionable! However I expect this to happen by at least the first ten days in June which will allow the Azores high to ridge across the UK initially into western areas and then across all areas. It will probably settle over Scandinavia or mainland Europe for a while with a hot period likely towards the end of June ESP in southeastern areas. The rest of the summer although unlikely to be a 2006 repeat is likely to be the warmest and sunniest summer since the famous 06 summer! However there will be unsettled spells more especially in August. July is the one to watch with a drier than average month quite consistently progged by the CFS v2 model. The fly in the ointment to my predictions will be whether the upstream patterns can continue to thwart the possibility of la nina conditions developing. If an active MJO continues along with positive angular momentum - then I don't see this an issue, however August is most at risk from a la nina type developing which would in turn mean a more unsettled cooler month.Overall I predict a decent summer but probably not a memorable one.For stats I am looking at a CET of around +0.5c above avg for 1981-2010 (June, July and August). Rainfall I expect to be varied with thunderstorms likely at times - however over England and Wales 90-95% can be expected with sunshine probably ending up 105% of average.Add me on twitter@alexbweather - for more of my weather views!

I'm rather pleased at how this has gone so far!@alexbweather

[cooling climate]

 

 

I still remain unconvinced of our ability to make accurate LRF. Im not picking on anyone in particular but one of the main problems with internet LRF is they all seem biased. What I mean by this for example is many of us love the cold weather & extremes and because of this we seek signals that point towards cold and possibly ignore those that hint at mild. Take for example another well known forecaster who I won't mention and does not post on this forum is always predicting mega blizzards with 200mph winds and a few twisters thrown in at the same time. These forecasts from this person are always OTT but they catch the eye and make great headlines!This is one of the reasons why I don't make any LRF. Firstly I don't have the scientific knowledge and secondly I don't think I could resist allowing my bias to affect my judgement and as a result I would be predicting endless E,lys. I prefer to stick with the models and look at the Met O 6-30 day forecasts.Many should follow the example of John Holmes. I know JH doesn't produce LRF but does post his thoughts on what the next few weeks may be like. Now in all the years of being on this forum I haven't known John to post anything but an honest interpretation of the charts with no bias whatsoever. I also like the methods John uses.So basically if someone produces a LRF that is less dramatic and more in tune with our climate im more likely to read it. If anyone is hinting a record breaking blizzards or hurricanes then I won't bother.

 

 

Just spent some time reading through the various LRF's and although they probably are fun to do they do

seem to have little worthwhile value. It is also interesting to see that the forecasters percieved  views and

summary (accuracy) of his or hers LRF has little bearing to what was actually written.

Edited July 16, 2013 by cooling climate

[cooling climate]

The peek ahead to summer as promised is encouraging; July has the same above normal output that was shown last year in August, where a +1 to +2 anomaly was verified. Therefore unless my research uncovers a lot of new variables that I wish to incorporate, the outlook would be for a warm to hot month of July.

 

Forecast made from over 4months out 10/10

[UV-RAY]

 

 

 

I still remain unconvinced of our ability to make accurate LRF. Im not picking on anyone in particular but one of the main problems with internet LRF is they all seem biased. What I mean by this for example is many of us love the cold weather & extremes and because of this we seek signals that point towards cold and possibly ignore those that hint at mild. Take for example another well known forecaster who I won't mention and does not post on this forum is always predicting mega blizzards with 200mph winds and a few twisters thrown in at the same time. These forecasts from this person are always OTT but they catch the eye and make great headlines!This is one of the reasons why I don't make any LRF. Firstly I don't have the scientific knowledge and secondly I don't think I could resist allowing my bias to affect my judgement and as a result I would be predicting endless E,lys. I prefer to stick with the models and look at the Met O 6-30 day forecasts.Many should follow the example of John Holmes. I know JH doesn't produce LRF but does post his thoughts on what the next few weeks may be like. Now in all the years of being on this forum I haven't known John to post anything but an honest interpretation of the charts with no bias whatsoever. I also like the methods John uses.So basically if someone produces a LRF that is less dramatic and more in tune with our climate im more likely to read it. If anyone is hinting a record breaking blizzards or hurricanes then I won't bother.

 

 

Just spent some time reading through the various LRF's and although they probably are fun to do they do

seem to have little worthwhile value. It is also interesting to see that the forecasters percieved  views and

summary (accuracy) of his or hers LRF has little bearing to what was actually written.

 

Having spent years reading them and having a bash at guessing them, I've come to the conclusion that we are no nearer now at making LRF than we were 50 years ago. All we can do is look at the long term signals and hopefully nothing out of the blue comes along and bins the forecast before it's had chance to get off the ground.

[Roger J Smith]

In the interests of accurate discourse, the post by cooling climate two posts back makes it appear as though my quote includes his own words. The last sentence in the "quote" is his assessment, not anything I said four months ago. Thanks for that, by the way, but a casual reader is going to think it's a quote of my own assessment somewhere else on the thread or the forum, which it wasn't. Also along these same lines, the post before that shows me saying nothing followed by Eye in the Sky and some other person making a comment that the quote box might have you believe that I made. Looking back in the thread, nobody every quoted the post from Eye in the Sky so there again I have to assume the comment at the end is from cooling climate.

 

I'm hoping these two posts can be edited so they show quotes attributed properly.There seems to be no reason for my name to appear in the first of the two posts. Note in passing that the post by Sceptical Inquirer then quotes the misattributed quote from me. He could also edit out that part as the logic of the quote boxes suggests that I made a statement that I think cooling climate actually made.

 

Anyone coming into this discussion for the first time will currently come away with an entirely false impression of what I have said earlier in this thread.

Edited July 16, 2013 by Roger J Smith

[Catacol]

Wow - the turn around in the Glosea4 long range predictor is about as stark as you'll see. Just check the difference between the June run and the July run published today. Sept - Nov has gone from a 60 - 80% chance of being below normal to a 60-80% chance of being above normal. Long range forecasting by computer model still looks a mess to me.

 

http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/glob-seas-prob

[summer blizzard]

Looks like a move to la Nina as well there.

[cooling climate]

In the interests of accurate discourse, the post by cooling climate two posts back makes it appear as though my quote includes his own words. The last sentence in the "quote" is his assessment, not anything I said four months ago. Thanks for that, by the way, but a casual reader is going to think it's a quote of my own assessment somewhere else on the thread or the forum, which it wasn't. Also along these same lines, the post before that shows me saying nothing followed by Eye in the Sky and some other person making a comment that the quote box might have you believe that I made. Looking back in the thread, nobody every quoted the post from Eye in the Sky so there again I have to assume the comment at the end is from cooling climate.

 

I'm hoping these two posts can be edited so they show quotes attributed properly.There seems to be no reason for my name to appear in the first of the two posts. Note in passing that the post by Sceptical Inquirer then quotes the misattributed quote from me. He could also edit out that part as the logic of the quote boxes suggests that I made a statement that I think cooling climate actually made.

 

Anyone coming into this discussion for the first time will currently come away with an entirely false impression of what I have said earlier in this thread.

 

Yes apologies for that. I am not sure how or why it happened, I tried to edit but it

would not let me so again apologies.

[Roger J Smith]

No worries, at least we tried to fix it up. I ran the winter 2013-14 part of my research model after spending a couple of hours checking out the input (if a column in the excel file ends the factor stops chipping into the overall model). The output looks milder than any winter since 2008 anyway, but there is a cold spell in mid-January. Otherwise most of the season looks rather mild. Will do a lot more work on this forecast before October, so that's just a very preliminary thought about winter 2013-14. Posted elsewhere my thoughts on the autumn ahead.

[Summer Sun]

No worries, at least we tried to fix it up. I ran the winter 2013-14 part of my research model after spending a couple of hours checking out the input (if a column in the excel file ends the factor stops chipping into the overall model). The output looks milder than any winter since 2008 anyway, but there is a cold spell in mid-January. Otherwise most of the season looks rather mild. Will do a lot more work on this forecast before October, so that's just a very preliminary thought about winter 2013-14. Posted elsewhere my thoughts on the autumn ahead.

 

Thats what I like to hear the last 2 winters have been way too cold for me

 

[UV-RAY]

Thats what I like to hear the last 2 winters have been way too cold for me 

Last winter was a non event until Spring really, the thought of a mild and probably wet winter doesn't inspire me the least

[Summer Sun]

Last winter was a non event until Spring really, the thought of a mild and probably wet winter doesn't inspire me the least

 

Mild doesn't instantly mean wet though south westerly winds would bring a lot of cloudy but mild air with it

[summer blizzard]

Last winter was a non event until Spring really, the thought of a mild and probably wet winter doesn't inspire me the least

The second half of Jan was great.

[UV-RAY]

The second half of Jan was great.

IYBY not in mine Lol.

Mild doesn't instantly mean wet though south westerly winds would bring a lot of cloudy but mild air with it

Agreed, but it generally is wet when mild in winter. It's just as well I take all LRF with a pinch of salt, though Roger is generally pretty close, but not always.

Edited July 21, 2013 by Sceptical Inquirer

[summer blizzard]

Attempting a more experimental forecast method...

 

QBO (Positive)

 

2008

2004

1999

1997

1995

1990

1985

 

MEI (Neutral-positive)

 

2012

2005

2004

2002

2001

1995

1994

1991

1990

1980

1979

1969

1965

1957

1953

 

PDO (Neutral)

 

1989

1959

1957

 

GLAMM (Neutral-positive)

 

2004

1990

1988

1987

1981

1978

 

April-May

 

1990

2004

 

1957

1995

 

 

abb

baa

baa

baa

aba

aba

 

June: 50% chance above/below average (range is 13.6C-15.3C)

July: 50% chance above/below average (range is 15.8C-16.9C)

August: 84% chance above average (range is 17.6C-18.0C)

 

Attempting a more experimental forecast method...

 

QBO (Positive)

 

2008

2004

1999

1997

1995

1990

1985

 

MEI (Neutral-positive)

 

2012

2005

2004

2002

2001

1995

1994

1991

1990

1980

1979

1969

1965

1957

1953

 

PDO (Neutral)

 

1989

1959

1957

 

GLAMM (Neutral-positive)

 

2004

1990

1988

1987

1981

1978

 

April-May

 

1990

2004

 

1957

1995

 

 

abb

baa

baa

baa

aba

aba

 

June: 50% chance above/below average (range is 13.6C-15.3C)

July: 50% chance above/below average (range is 15.8C-16.9C)

August: 84% chance above average (range is 17.6C-18.0C)

 

Coming toward the end of the summer and my June and August predictions look pretty good to me, July was a bust though.

 

.............................

 

Preliminary Autumn forecast (will update a final version next month).

 

September: 80% chance above average (range is 15.1C-15.6C).

October:  80% chance above average (range is 10.9C-12.6C)

November: 60% above average (range is 7.9C-8.1C)

[snowking]

Coming toward the end of the summer and my June and August predictions look pretty good to me, July was a bust though.

 

 

Same here. Saw the settled spell coming but didn't expect the temperature profile that accompanied it, and it was longer in duration than anticipated.

 

But overall I have been happy with the QBO/ENSO blend for composite years I used - the key details were the three main settled spells of the summer forecast - Early June, Mid July, and Late August. So far its sort of 1.5/2, hoping to make that 2.5/3 as this settled spell develops later next week (making of course the huge assumption that it does so!).

 

The most significant part of the Autumn forecast for me remains the story carrying over from the very early thoughts based around the summer composite years - and this is of the continuing strong signal for a very settled October. After an unsettled start, it looks as though it will be high pressure dominated.

 

Taking it further beyond that, and the other strong signal seen over the last 6 months is for a very cold February - something that I know Roger disagrees with based on his preliminary thoughts. I do agree with him about the mid-January spell though, certainly a signal there based upon the composite years....February still looks the main month though for me.

 

SK

[BornFromTheVoid]

Here's my finalised Autumn forecast.

 

I used 8 different criteria based on the teleconnections and the trends they've exhibited in recent months, and checked each previous year, back to 1951 (except for sea ice, which only goes back to 1979) to see how many matches each year got with this.

Below are the different criteria used (I can give the exact numerical conditions used if anyone wants them)

 

• Arctic Oscillation (AO).   Condition - That there was a strong trend from a -ve Winter AO to a +ve Summer AO
• North Atlantic Oscillation (NAO). Condition - Moderate trend from a -ve Winter AO to a +ve Summer AO
• El Nino Souther Oscillation (ENSO).   Condition - A slow trend from a moderately -ve ENSO value in Winter, to weak -ve values in Summer and neutral values in Autumn, based on the ENSO 3.4 region anomaly.
• Quasi Biennial Oscillation (QBO).   Condition - From -ve values at the beginning of the year to strong +ve values in Summer
• Solar Activity, Sunspot Counts. Condition - Mean 11 year monthly sunspot count below 70
• Atlantic Multidecadal Oscillation (AMO). Condition - January to July mean of between 0 and +0.3
• Pacific Decadal Oscillation (PDO). Condition - January to July mean of between 0 and -1.5.
• Sea Ice Area (SIA). Condition - September SIA of less than 4 million km2

 

Of those criteria, 3 years matched 5 of them (2006, 2001 and 1969) and while 4 years matched 4 criteria (2012, 2011, 2008, 2002).

So when creating the composite maps, the years with 5 matches were added twice and the years with 4 matches were added just once. All other years were excluded.

 

 

SEPTEMBER- General Pattern

 

 

September shows strong heights nearby, but centred slightly to out north and east. This would indicate a good deal of settled weather during the month, with more of an easterly flow than usual and a continuation of the +ve or near neutral NAO seen during the summer. The signal for +ve heights isn't very strong though, and so some unsetteld weather should be expected.

 

Temperatures are likely to be above the 81-10 average in most areas. A CET of close to 14.8C is my guess

Rainfall is likely to be close to or slightly below average in general.

 

 

OCTOBER - General Pattern

 

 

 

October shows a good signal for strong heights to our south east, indicating a ridge into central and western Europe. This pattern may result in an increased southerly component to our weather. Conditions will be most settled toward the south east, with increased Atlantic influences further north and west.

 

Temperatures likely to be well above the 81-10 average for all areas in the southerly winds, but more so in the south east. Some very mild or warm conditions could occur. A CET of close to 12C is my guess.

Rainfall is likely to be close to average overall, perhaps slightly below in the south east, and slightly above to the north west.

 

 

NOVEMBER - General Pattern

 

 

Confidence at this range drops significantly. However, current indications are that November may see a change, with a strong signal for low heights to our north and ridging to the south of Greenland, while the Euro ridge weakens further south and east. This indicates that the whole of the British Isles, but especially northern areas, will see spells of unsettled weather from the west and north west. With the strong Atlantic ridge and weakening Euro ridge, parts of western Ireland and south east England may see slightly more settled conditions at times.

 

Temperatures are likely to be close to or slightly above average in most areas, with the greatest chance of above average conditions being in the south east again. A CET of about 7.8C is my guess.

Rainfall is likely to be slightly above average in general, with western Ireland perhaps being below average due to the influence of the Atlantic ridge.

 

 

Autumn Overall.

Best chance of long settled spells in September and October, with the best of these towards the south east. More general unsettled conditions in November.

Temperature wise, a well above average Autumn overall, possibly reaching the top 10 warmest on record.

Rainfall is predicted to be close to, but slightly above average overall. The west of Ireland, being the most likely to see below average rainfall.

[johnholmes]

Thank you for that, a lot of research and work has gone into that, like you we now have to await what the weather brings.

thanks for all the time and effort-much appreciated.

 

for comments on your work I will leave it to those who profess to have a good knowledge of all the factors you mention.

Edited August 22, 2013 by johnholmes

[BornFromTheVoid]

Thank you for that, a lot of research and work has gone into that, like you we now have to await what the weather brings.

thanks for all the time and effort-much appreciated.

 

for comments on your work I will leave it to those who profess to have a good knowledge of all the factors you mention.

 

Cheers John.

I don't profess to have a technical knowledge of the interactions of some factors I included, but I'll answer what I can.

[Isolated Frost]

Based purely on Arctic oscillation- and general June-July pattern, my autumn prediction. BFTV, a lot of it resembles your forecasts very well.

 

September

Temperatures slightly above, especially in the east. Precipitation about average, or slightly below.

 

October

Temperature slightly above, especially in the south. Precipitation average, slightly higher in the north and west.

 

November

Temperature strongly above, especially in the east. Precipitation above average, strongly.

[Alex]

My 2013 Autumn Forecast by Alex B

I am sure most will agree that Summer 2013 will go down as a good one however I doubt it will be said in the same breath as 76 or 2006, but it has been a big improvement on recent summers!

How is Autumn going to shape up? Lets look at some of the upstream patterns first - tropical activity has been weak during August and this has kept us in a very typically average August pattern. However during the last few days we are starting to get an eastward propagation - this is important as enhanced activity in the Western Hemisphere at this time of the year equates to some cooler weather down the line.

Sea state temperatures are generally average to above normal around our shores this could enhance rainfall and help keep temperatures slightly above normal.

Sunspot activity has been more active this summer and I expect this to continue into the autumn, although not proven - reduced activity correlates well to a southerly tracking jet.

ENSO forecasts favour a continuation of neutral conditions - therefore la nina / el nino anomalies are not evident enough to discuss in any detail.

For seasonal forecasting I use a model called CFS v2 - it did a very good job in helping me to predict the very decent July just gone! Tracking it over a period of time can indicate what it's favoured direction is! One of it's strongest trends for this Autumn has been for a drier/warmer October than normal.

There are other longer term variables that come into play, PDO (pacific decadal oscillation) is one such variable and this is like a longer term el nino or la nina phase. We are currently in a cool cycle.

So in summary of above

* Tropical activity indicates a gradual cooling of our temperatures into September with pressure likely to be low to the east of us.

* Sea state temperatures around the UK are average or even above normal.

* Sunspot activity although still relatively weak, it has been more active than some recent years.

* CFS v2 - strongly supporting a good October in terms of warmth and reduced rainfall.

* -PDO autumns have been generally warmer and drier than normal, 2011 is one example.

What do I expect?

September - The NW/SE split is likely to continue at first but gradually becoming cooler and more unsettled everywhere with probably the best weather in the west midmonth and rather cool everywhere. The end of the month is likely to see a return to more settled conditions and perhaps slightly above normal temperatures as a result.

October - Becoming increasingly settled with some reasonable days, however with the longer nights comes the threat of fog and maybe frost at times especially in northern areas. An easterly flow is likely for the first half of the month but it is likely to be relatively warm air. During the latter half it may become more changeable in the west, the southeast could hold onto more fine weather though.

November - Becoming unsettled at first but temperatures will hold up well with some mild nights at first, during the second half there is a small signal for a colder drier regime with some frosty nights likely.

Summary - I expect rainfall will stay slightly below normal but there will be some local differences. Temperatures likely to be near or above normal.

For stats I am predicting

Rainfall - 90%

CET Temperatures of - +0.5c

Sunshine - 105%

@alexbweather

[Summer Sun]

Sounds good to me Alex I would settled for that

 

[Summer Sun]

A trend I've noticed for a while now on the netweather long range forecast maps is for December to have very low rainfall across the UK

 

 

Temperatures also look fairly average and maybe slightly above in some parts

 

 

A long way to go yet till December but I shall continue to watch the rainfall trend and see how things go over the next few month

[feb1991blizzard]

A trend I've noticed for a while now on the netweather long range forecast maps is for December to have very low rainfall across the UK

 

 

Temperatures also look fairly average and maybe slightly above in some parts

 

 

A long way to go yet till December but I shall continue to watch the rainfall trend and see how things go over the next few month

 

 

TBH If December has below average rainfall then I very much doubt it will be a warm December, Even one of those dreaded circular highs anchored to the West of us wouldn't produce a very warm December due to the low strength of the sun, it would need to be the ridging North of a Bartlett and even then it might only be dry for the South.