Our Chief Scientist Professor Dame Julia Slingo OBE FRS reflects on this summer’s weather and what has influenced it:
No-one can deny that we have had a pretty disappointing summer with a lot of unsettled weather and only a few warm spells, especially through July and August. Our weather has been dominated by low pressure over and to the west of the country that has brought us periods of heavy rain from the south – what we call the Spanish Plume. So what has been happening?
If we look beyond our shores there have been some big changes in the global climate this year. El Niño is in full flight, disturbing weather patterns around the world. The low pressure that has dominated our weather is part of a pattern of waves in the jet stream around the world that has brought crippling heat waves to places like Poland and Japan. And, looking back over past El Niños, you could have expected that a more unsettled summer might be on the cards for the UK. Closer to home the North Atlantic is more than 2 degrees colder than normal. It seems quite likely that the unusually cold North Atlantic has strengthened and pushed our jet stream south, also contributing to the low pressure systems that have dominated our weather.
So could all this have been anticipated? Seasonal forecasts for this summer suggested that temperatures and rainfall would be near normal. However, as the season progressed all the leading models around the world failed to capture the signal for unsettled weather over the UK. We all know that forecasting months and seasons ahead is still in its infancy and much more research needs to be done. On the other hand our day-to-day forecasts have been really successful in allowing us to warn of bad weather, highlighting yet again the benefits of our research that has delivered year-on-year and decade-by-decade improvements in forecasting skill. Our 5-day forecast is now as accurate as our 1-day forecast was when I started my career. This enables us to make so many decisions that keep us safe, protect our property, keep our infrastructure running and even when to go out and enjoy the sunshine!
All of this cannot happen without improvements to research and technology, and this week the first phase of our new supercomputer went live, five weeks ahead of schedule. This will enable us to provide even more accurate and relevant weather and climate forecasts to all of us, our government, emergency responders, and our many other customers at home and abroad.
The news that the BBC has decided that the Met Office won’t be their main weather provider when the current contract ends has raised the question of where will the new provider get their information from. It’s important to understand that no weather forecasting organization, whether it is a National Met Service like the Met Office or an independent company, can provide a service without a forecast, and that it is the leading meteorological agencies, like the Met Office, that build and deliver those forecasts. So whoever the BBC chooses to deliver their weather services in future, you can be sure that Met Office observations and forecasts will continue to be at the heart of them. We are committed to driving forward the skill and usefulness of our forecasts and ensuring that all of us benefit from the advances the Met Office makes in the coming years with our new supercomputer.
“So, could all this have been anticipated?” Yes, it could if anyone had bothered to apply the work of H H Lamb and others with regard to SST anomalies in the area south of the Grand Banks.
Here’s what I published on uk.sci.weather on June 15:
“There is a belt of warm water mainly between 30 and 45N with cold to
the north of that. That suggests a zonal pattern this summer with a
belt of lower than normal pressure lying W-E between Iceland and
Scotland. A W-E belt of higher than normal pressure should be situated
near the Azores.
“This suggests a cool, cyclonic, and damp summer. However, although the
cold water to the west of the UK should keep temperatures down, it may
also reduce the amount of moisture in the atmosphere and so rainfall
may not be a high as one would usually expect in this situation. Also,
the orientation of the boundary between the warm and cold water is
slightly tilted, more 260-080 degrees than 270-090. This may keep
pressure slightly closer to normal over southern England.
“Anyway, cool, damp, breezy, particularly in the NW.”
OK, it’s not perfect, but I think it shows that ignoring Lamb’s work is a mistake. Just because it was formulated fifty years ago, does not mean it is past its use-by date.
I find it strange that some studies seem to ignore climate before the 1970s. It’s almost as if giving them a copy of Lamb’s British Isles Weather types and a register of daily sequence of circulation patterns, 1861-1971 will present a ‘eureka’ moment.
I’m confused. How does this:
looking back over past El Niños, you could have expected that a more unsettled summer might be on the cards for the UK
fit with this (from the JJA summary for policy makers)?
However, El Niño is not known to have a significant influence on the climate across northern Europe at this time of year.
In the North Atlantic, sea surface temperatures to the south of
Greenland are cooler than in recent years; this pattern of sea-surface
temperatures is thought to increase the probability of above-average
pressure over northern Europe in summer. At this time of year such a
pressure pattern is often associated with above-average temperatures.
El Nino has an effect but it doesn’t. Cold Atlantic SST cause high pressure and low pressure? Which is it?
Btw you could have followed the old ‘Be wary of warm and sunny Aprils’ for this summer and not gone far wrong. No super computer (££££!!!) needed 😉
Craig, the cold area in the Atlantic, on its own, does not cause low or high pressure. The important area to watch, as Lamb &Co discovered over fifty years ago, is that to the south of the Grand Banks where there is a strong temperature contrast between the Gulf Stream and Labrador current. This area tends to be the main spawning-ground for Atlantic depressions. If the SSTs in the area are warm, depressions have more energy and the Icelandic Low becomes deeper than average and a little further east. A cold pool in that area leads to higher than normal pressure over Iceland. The shape of the anomalies also makes a difference to the resultant pressure patterns.
It’s a pity that my ex-colleagues at the Met Office seem to be neglecting the fine work of H H Lamb and others. Presumably it’s old and so is no longer of any importance. Like me? 😉
Agree Graham, Lamb did some fine work. I always keep reruning
*returning to his analysis. It was based afterall on analysis of what has been – it still holds well.
Am really interested in the above 2 comments, and indeed the possible explanations for this year’s poor July/August – clearly by folk far more clued up on meteorological influences that I am.
As smallholders in Wales our whole work patterns are weather determined. So we scan forecasts, ( 3 different sources) particularly around hay making time, with great interest. I would have to tell Dame Julia that this year the BBC publicised, but apparently Met Office generated, forecasts – in particular the rolling 4 hour maps showing cloud cover and precipitation, have been extremely disappointing. On several occasions they have completely missed significant (hay wrecking) rain episodes, whilst, for example the XCWeather forecast charts have more accurately picked up on the likelihood of rainfall. ( Do they have an even more expensive computer. I wonder, or use different parameters in arriving at their forecasts?) I appreciate the problems with forecasting, but from the pattern of weather in this part of the world this summer, I do question the assertion above of the accuracy of predicting the weather even just a few hours ahead.
Of course all this inaccuracy over a 24 hour period does raise the conundrum of whether we really know that we’re heading for rising temperatures in the UK with global warming- sorry- climate change- or as has surfaced recently, the probability of a mini ice age within 15 years.
Which does Dame Julia think we should plan for?
So to sum up, another computer model fail.
If the computer models can’t even get the forecasts right two or three days in advance, as we have continually seen this year, how can it be claimed that the Met Office will now be able to produce “accurate and relevant climate forecasts” when they are derived from essentially the same model.
“looking back over past El Niños, you could have expected that a more unsettled summer might be on the cards for the UK”
So why was it “unexpected” then?
Of course the 3-month Outlook stated:
“However, El Niño is not known to have a significant influence on the climate across northern Europe at this time of year.”
Slingo would not survive two minutes in a proper job.
‘Quentin Letts: Another member of the committee has been the veteran Conservative Peter Lilley. Does he get lobbied by the Met Office?
Peter Lilley: I suppose we do get lobbied by them. They come before the Select Committee on Energy and Climate Change, on which I sat, and tell us they need even more money for even bigger computers so they can be even more precisely wrong in future…’
Statistics for my part of east London (Wanstead) show that it has been a very average summer up to 28th August, if rather dull (84% of average sunshine). Bracketed figures represent the 1981-2010 average for this area,
Mean 17.9C (17.6C) Rainfall 151.7mm (144.9mm) Sunshine 472 hrs (564hrs)
The comparison with 1997 suggests that this El Nino is having less of an effect despite it being in the same league as that ENSO. 1997 figures were:
Mean 18.5C Rainfall 226.1mm Sunshine 497.9hrs
IRI statistical link between rainfall and El Nino suggested normal or above normal rainfall for most of UK this summer.
Above normal probabilities
Global producing centres output varied somewhat but a rough summary for Summer 2015 based on May data was:
Summary 220515 – main theme near normal or a little above normal temperatures overall and above normal rain in places after probably a drier start to summer.
Summary 170515 – BCC China supports slightly wetter and slightly cooler / close to normal
Summary 160515 – JMA implies weakly unsettled summer and hints at slightly cooler with slightly higher rain totals but consensus (including IMME) favours near normal temps. A risk of higher rain totals in S and E than normal occurs in some output.
Summary 110515 – indication for normal temps but in S possibly above normal. Indication for drier than normal in several models early/mid summer but less agreement for later in Summer. Some risk of above normal rain in parts of S of UK (could be thundery rain?).
Note 110515: The last 4 monthly issues of NMME/CFS2 have indicated drier start to summer and wetter August, although location of wetter area N/S has moved south with time. Temps mostly above normal or normal.
So there were some hints that all was not great for summer 2015,
I had the met office app on my phone but I got so fed up with it being so wrong I uninstalled it, couple of days later the BBC did the same.
craigm350 You subscribe and promote someone who is wed to political and financial gains. Until your divorce we will sadly have to ignore you.
elim said ..wed to political and financial gains… let the money for forecasting go out to tender and be awarded to those who can demonstrate the best skill. I can assure you if those are the criteria Met would not win it.
Slingo wrote “However, as the season progressed all the leading models around the world failed to capture the signal for unsettled weather over the UK.”….. there is a model of climate reality that does predict it but its not based on co2 as cause.
Basically its impossible to get any kind of weather climate job without taking the oath of allegiance to co2 so do not expect any of them to go against the Met vatican decree of co2 as cause.
As science has a prove predict model then until Met can predict they have proved nothing with their ‘settled science’ and so can be and should be ignored. Lets return to science not middle class eco religion hand wringing beliefs that want to destroy society and go back to living in mud huts.
Ulric Lyons has been extremely accurate this year and, as usual, been ignored by the establishment. He posted on this blog in April(if I remember correctly) and I posted his uk centric forecast on the agwbs dot com site in March and haven’t posted anything else yet (the global warming thing wore thin with me a long time back). I will probably only post his forecasts there from now on.
He has shown exceptional skill and, yes, the majority of the details were ‘ … wetter and colder …’
The MET Office, indeed the country as a whole need to pay attention to him but they wont as they are completely wed to ‘it’s the monkys burning stuff that caused the warmy, warmy’. Such a shame.
To be fair I doubt if the MetO have heard of me or seen my forecasts until I posted my LRF here earlier this year. And any human influence on climate makes no difference to the utility of the forecasts. From what I can, see low solar periods cause negative NAO episodes to the same degree regardless of average global surface temperature, with extreme daily negative NAO values occurring in e.g. 2009/10 and Mar 2013, not seen since previous solar minima.
With that in mind are we looking at repeat of 2009/10 winter ie cold?
On the link just below is my Winter and early Spring solar forecast element. Similar extremes of negative NAO/AO are likely in the noted periods. Regional distribution of Arctic incursions does depend on blocking patterns and QBO etc, and with the NE Pacific warm blob now dissipated, and a cooler N Atlantic, the UK would be more open to the cold shots.
July and August were very much as I had forecast. Third comment down:
Just comparing temps with CET daily values from xmetman and the forecast. Was it different for the whole of UK?
From March 18/20 a sharp cold snap — no there was not
Slightly milder 2nd week April —- 1 and 2nd week simialar
Very warm from April ~15 —– was slightly cooler in second half April
Cooler and wetter from around April ~29 — cooler started 26th lasted till 3 May
Warmer from May ~17 —- and May remained mostly cooler
Warm burst from ~25 May —- no there was not
Cooler and wetter ~4-9 June — 4 June milder then colder for a few days
Strong warmth from 10/11 June************* — warmer spell from 23rd June
Cooler and wetter from ~24 June —- warmer spell from 23rd June
Possible few warmer days from 29 June (not certain) — was in a warmer spell
Cooler and wetter from 5-7 July — near normal temps
Possible few warmer days from July 19 (not certain) — colder spell started 22July lasted into August
From July ~29 a strong warm burst************ — colder spell started 22July lasted into August
Weaker warm burst from 8/9 August – yes was a weak warm burst colder from 11th
Cooler and wetter from August ~20 – milder then colder from 23
Possible few warmer days from August ~25/26 (not certain) — colder
From September ~4 cooler-wetter — started cooler 9 to 15 slightly milder
Anonymous Mike said
“was slightly cooler in second half April”
It was not a very warm burst, but it was mostly above normals.
” — colder spell started 22July lasted into August”
Rubbish, it warmed to above normals from near the end of July.
“Possible few warmer days from August ~25/26 (not certain) — colder”
It did slightly warm up for few days for the UK from the 26 Aug.
Leave it to the MetO to do the verification Mike, you were not invited.
I am sure that I cannot be the only one who remembers being told a few years ago that the UK was more likely to experience warmer, wetter summers in the future. Now we have just been told that the likelihood if for future ones to be both cooler and drier. It is surely understandable if the public have relatively little faith in much accurate forecasting beyond the very short term. The Met Office itself confirms this by the wording on this blog where, although we are already into autumn, it states “that it is far too early to speculate about what sort of winter the UK will have”. If it is too early in mid September then exactly when will it be appropriate to speculate? Perhaps it has late January in mind!
I occasionally issue seasonal forecasts based on SST anomalies. I would not issue a Winter forecast this early as I’ve noticed that SST patterns can change significantly towards the end of Autumn. I suspect that it may be connected with changes in temperature contrasts between land and sea that occur at this time of year.
Techniques for short-term and long-range forecasting are totally different. Just because the accuracy using short-term forecast techniques becomes worthless a fortnight ahead, say, that means nothing with regard to accuracy of long-range forecasts.
At the end of the 1960s, I even noticed something that allowed me to correctly make a forecast for several years ahead. That was using yet another different technique that would have been of little or no use for making a forecast for the following month or two. It’s also quite possible that what I saw happening in the sixties was a one-off and wouldn’t occur again.
Was summer so bad ? Although rainfall total amounts for the summer were above average, around the Exe Estuary the number of rain days were close to average – the drier June offset by above average days of rain in August. No disputing August was wetter in parts of UK. For the Midlands and parts of NE England there were more rain days in July than August but overall not far from normal rain days for summer as a whole. Perhaps Global Warming could mean larger rainfall totals – I am sure I heard that somewhere. Perhaps not more wet days – who knows?
Further if you were a youth of the 60’s and 70’s then it was a near normal summer with regards to mean temperature (see 1961-90 mean temp anomalies compared to 1981-2010). For younger ones though, it was cooler! That’s what happens when the climate warms and your reference period changes.
Can’t really complain here in Wanstead, East London: Mean temp 0.3C above average Rainfall 116% Sunshine 84%
August was pretty lousy – it is always the most recent month that people remember, so whole summer gets tarred with the same brush. The last few years summer seems to be happening earlier – April was a smashing mont again with August becoming more like an autumn month. I read somewhere that years ago August was always thought of as an autumn month because it was harvest time and most people had to work hard in the fields getting the crops in.
The media seems to struggle to comprehend the ever changing climate…
Clearly London was nothing like most of the country. In Scotland it has been so cold and wet that many people are referring to 2015 as the year without a summer. Trees were around three weeks later than average in gaining leaf cover, and harvest has been around 17 days later than average.
Interestingly Luke Howard mentioned that a lunar eclipse occurred during the year without a summer on December 5th 1816. It was not visible, however, because of cloud and rain. This was preceded by a solar eclipse reported in Augsburg, Germany, the previous month on 19th. I would have thought that such an eclipse would have been partial in this part of the UK.
It is interesting that both a solar and a lunar eclipse occurred when there was a poor summer in the UK.