Met Office continues to drive forward research on long-range forecasting

29 03 2013

The BBC Radio 4 ‘Today’ Programme have run a story this morning regarding the advice the Met Office gave to our government customers ahead of the exceptionally wet weather of April to June 2012.

This was an extreme period of weather that saw a marked change from dry conditions to very wet conditions in a very short period of time.

Following the exceptionally wet weather of late spring 2012 the Met Office provided a full report into the possible reasons for the switch from dry to wet conditions. Our report states that the advice provided in the long-range outlook for April to June 2012 issued in March 2012 ‘was not helpful’ to our government customers.

However, looking at the skill of these outlooks over many individual forecasts clearly shows that they provide useful advice to their specialist users on over 65% of occasions. In addition these outlooks are never used in isolation but form one part of a range of forecasts from the Met Office including regular monthly outlooks and highly accurate 1 to 5 day forecasts and warnings.

Facing up to the challenge of long-range forecasting

The science of long-range forecasting is at the cutting edge of meteorology and the Met Office is leading the way in this research area. We are continuing to work hard to develop the science of long-range forecasting. We are confident that long-range outlooks will improve progressively and that the successes we have achieved in other parts of the world already will, in the future be mirrored in the UK.

The Met Office constantly reviews the accuracy of our forecasts across all time scales and is recognised by the World Meteorological Organization as one of the top two national weather forecasting services in the world. We also routinely verify our short-range forecasts on our website.

The ‘big switch’ of April 2012

During March 2012 the La Nina event that had persisted from 2009 was finally waning in the Pacific (as predicted by the seasonal forecast system), although many parts of the global oceans and tropical weather patterns still retained characteristics associated with La Nina. In the northern hemisphere the jet stream was very disturbed, resulting in a wave pattern of high and low pressure regions. The UK was positioned under a strong high pressure region resulting in very dry and warm conditions. In April, the wave pattern underwent a significant shift to bring the UK under the influence of strong low pressure, with prevailing south-westerly flow and heavy rainfall.

As detailed on ‘Today’, one of the potential causes of this shift in the northern hemisphere circulation may have been associated with a shift in tropical weather patterns. In particular, this may have been caused by a strong Madden Julian Oscillation (MJO) which occurred in March. This is a large-scale tropical phenomenon which leads to disturbed weather patterns over a timescales of typically 30-60 days. This changes originating over the Indian Ocean may have influenced our northern hemisphere weather regimes. Understanding the initiation of an MJO event is, however, largely unpredictable, and remains one of the great unsolved challenges of tropical meteorology.

Due to the fact that the initiation of an MJO is largely unpredictable – combined with knowledge that often subtle, and sometimes small, shifts in hemispheric circulation patterns can make all the difference between fine, dry weather and unsettled, wet weather over the UK – it is very unlikely that its impacts could have been anticipated in any forecasts for the coming months issued in early and mid-March.

A complicated world

Finally, although one reason for the switch in the fortunes of our weather in 2012 may have been the MJO, there are other parts of the climate system which we increasingly recognise as having an influence on our weather patterns. These include the North Atlantic Ocean temperatures, solar variability, the circulation of the upper atmosphere – the stratosphere – and of increasing interest, the changing state of the Arctic.

Better understanding and representing the drivers of predictability in the global climate system that influence our weather patterns is as ever a priority for Met Office research in order to deliver improved advice and services on all timescales.


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13 responses

29 03 2013
Nigel Boldero

This is very interesting. I’m in the middle of a series of blog artcles on climate change and the garden (‘Four Seasons in One Day’- see http://www.audaxdesign.co.uk) and want to do an articie about how developments in information about different plant variety reslience, hardiness and if/how long term weather forecasting will improve the notice that gardeners and growers have of abnormal seasonal weather events and can therefore adjust their techniques, growing plans etc. Accordingly. I’d be grateful for any further information or advice you can give me on this- email nbold@btinternet.com.

I’ve also noticed that in the USA and Canada there are published ‘first and last frost’ days for major cities. Do such lists exist for the UK? I’m guessing that such information is unreliable given the variability in our weather, and that this may become even more so with the effects of climate change- can you comment on this too, please? Thanks in anticipation!

29 03 2013
Dave Britton

Nigel, Thanks for your query. The provision of longer-range forecasts is exremely challenging and always will be for the likes of NW Europe and the UK, where only small changes in driving factors can ahve a big influence on pressure patters, wind direction and therefore our weather. However the science of longer range forecasting is improving and jsut as we have seen huge improvements over the last 40 years or so in the provision of 3 to 5 day forecasts, we will see similar advances in long range forecasting in the future too.

The Met Office does not forecast first and last frost days in the UK, mainly as you say in that weather in the UK is much more variable than the large continental climates of the US and canada.

29 03 2013
Nigel Boldero

Thanks for that Dave, You’ve given me some optimism! If you have any comments or additions to my blog articles that would be much appreciated- ‘Old School Garden’ at http://www.audaxdesign.co.uk

29 03 2013
Nigel Boldero

Reblogged this on Old School Garden.

29 03 2013
argylesock

Reblogged this on Science on the Land and commented:
argylesock says… We need to know what’s likely to happen in our weather. People who make a living on the land or sea need to know what plans to make.

29 03 2013
leonard dawson

Dear Met Office,

Thank you for this-very very interesting.

By acknowledging the inexact nature of meteorological science and the many unknowns in the wider climatic picture (eg “MJO”-amongst others), then clearly computer modelling as a methodology for climatic prediction remains frought with difficulty.This will always be the case.

Nevertheless, best wishes for your ongoing excellent research.

L I DAWSON.

Iom: Met Office News Blog [mailto:comment-reply@wordpress.com] Sent: 29 March 2013 07:27 To: leonard.dawson@ntlworld.com Subject: [New post] Met Office continues to drive forward research on long-range forecasting

Dave Britton posted: “The BBC Radio 4 ‘Today’ Programme have run a story this morning regarding the advice the Met Office gave to our government customers ahead of the exceptionally wet weather of April to June 2012. This was an extreme period of weather that saw a marked cha”

29 03 2013
ntropyalwayswins

Is it not the case that because of the position of the UK we are always going to get very variable weather? That very variable weather makes up our ‘climate’. Is there anything to suggest that our weather and our climate will not simply continue to be ever changing with every extreme of weather that nature can throw at us – excepting perhaps tropical storms?

1 04 2013
Dave Britton

Yes, our weather will always be variable. That is part of the challenge of forecasting the weather in the UK.

30 03 2013
jdey123

Since you know that your forecasts are only accurate up to 4 days (assuming that the 1 day forecast in 1980 was reasonably accurate) then why do you insist on trying to predict weather and climate for periods longer than 4 days?

http://www.metoffice.gov.uk/about-us/who/accuracy/forecasts

Your 10 day, 1 month, 3 month, yearly, pentadal and decadal forecasts become more rubbish the further in to the distance you take them, yet you have no problem with signing up to a statement which says that you have considerable confidence in your climate models for projections up to 2100.

That is what diminishes your organisation in the eyes of the public – Your ability to mix science (analysing the accuracy of your forecasts up to 5 days) which is good, and political ideology (claiming that climate change is caused by man and that you have evidence of extreme weather, without providing any real data to support it) whiich is awful.

1 04 2013
Dave Britton

James, you are right that forecasts become less accurate the further ahead you look, but you are wrong to suggest they are rubbish. They provide useful advice to those that use them and understand there limitations. Away from forecasts for the next 5 days, which yyou agree are accurate, forecasts can only provide probabilistic information on possible outcomes and our 3 month guidance has been found to provide useful advice on over 65% of forecasts.

Providing shorter term weather forecasts however is different from providing climate projections. With weather forecasts we are forecasting the changes from our climate, or in other words its variability from day to day. When providing climate projections 50 to 100 yrs ahead we are actuall;y forecasting the average climate at this time. In the middle (3 month to 10 year predictions) we are combining both the weather and the climate. This si still at the forefront of scientific research, but we must continue to push forward with our understanding of the science – that is the role of the Met Office.

The Met Office does not ‘mix’ politcal ideology, but undertakes independent scientific research to increase our understanding of weather and climate, with partners across academia both in the UK and internationally.

30 03 2013
jdey123

So far this year, central England’s been colder than any year since 1890:-

http://www.metoffice.gov.uk/hadobs/hadcet/

Hard to explain why it’s so damn cold when basic physics suggests that CO2 has a greenhouse effect. Whenever I’ve been in my greenhouse, I’ve not found 1 part of it that remains significantly colder for prolonged periods of time. This is also true when I’ve been to that massive greenhouse they have at Kew Gardens. Climate scientists claim otherwise, however. The fact that Central England in 2013 has thus far been colder than all years back to 1890 and colder than the 1770s is apparantly just natural variability and we can’t expect everywhere to get warmer.

1 04 2013
Dave Britton

James,
When looking at the impacts of greenhouse gases on climate it is important to look at global and regional trends over longer periods of time than you suggest. Although the CET is a very important historical temperature record it only reveals temperatures over a small part of the UK, but does not reveal anything about wider changes across Europe or the Earth, not does it reveal anything about possible trends in rainfall, ocean temperatures, salinity or other measures of the Earths climate.

6 04 2013
jdey123

I think I dealt with all of that, Dave, in my original post. Weather pushes air around the earth on a daily basis. The UK has very changeable weather, making it one of the areas on the planet which should be least immune to global warming. An analogy would be if you stir a pot of water, you even out the temperature differences.

For the UK to have experienced negligible global warming in over 250 years and for you to dismiss it as an unrepresentative part of the planet, shows that what you’re peddling is ideology not science. You need to explain why the UK is not experiencing the levels of global warming, and why we are wasting billions of pounds on a mythical issue which isn’t affecting us.

Since I wrote the post, central England’s got even colder. Now, 2013 is colder than any year since the 1870s!

http://www.metoffice.gov.uk/hadobs/hadcet/

The whole earth has got colder since 2002. Again you’ll dismiss this as too short a period. When I heat my bath, it doesn’t pause for 10 years and then suddenly get really hot, due to upwelling from the bottom of the water or whatever nonsense you alarmists are coming out with this week. What ‘basic physics’ prevents global surface temperature from increasing in line with CO2 levels in the atmosphere? Do you seriously believe that heat can get trapped in the bottom of the ocean?

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