Readers may recall how the Met Office botched yet another forecast, calling for drought but instead getting a month of deluge. Here’s the numbers.
By Paul Homewood
The UK Met Office have just released their weather data for April, which confirms just how wet and cold the month has been. With an average of 126.5mm of rain, this has been the wettest April on records which go back to 1910. It was also the coldest since 1989, 0.65C colder than the 1971-2000 average.
This, of course, is in stark contrast to the 3 month outlook the Met Office issued on 23rd March, which told us that :-
SUMMARY – PRECIPITATION: The forecast for average UK rainfall slightly favours drier than average conditions for April-May-June as a whole, and also slightly favours April being the driest of the 3 months.
and
SUMMARY – TEMPERATURE: The UK-average temperature forecast for spring (April-May-June) shows a range of possible outcomes that are warmer than the range observed between 1971 and 2000 (our standard climatological reference period), but quite similar to the last decade. For April the forecast also favours temperatures being warmer than the 1971-2000 reference period.
http://www.metoffice.gov.uk/media/pdf/p/i/A3-layout-precip-AMJ.pdf
http://www.metoffice.gov.uk/media/pdf/q/q/A3-layout-temp-AMJ.pdf
So far (unless I have blinked),the Met Office Chairman, Robert Napier (formerly Chief Exec of WWF-UK), has not been doing the round of TV studios to apologise for getting things so badly wrong. But what about the longer perspective, with parts of England still officially in drought?
Figure 1 shows annual rainfall trends up to the end of 2011. The last 2 years have been dry, but are similar to many earlier years in the record, while the long term trend is remarkably stable.
Figure 1
Further analysis on the 2011 numbers by season and also by region is available here. (Again, this analysis shows that there is not much happening with long term rainfall trends and also that there was nothing particularly unusual about 2011).
Figure 2 shows the cumulative rainfall totals in England & Wales for January – April, both for this year and the 1971-2000 average. In most parts of the country, rainfall has been close to normal. Only the West and Wales have had significantly low levels, but these areas have not been in drought and generally receive much higher amounts of rain than the rest of the country anyway. Figure 3 gives the cumulative amounts for the last 16 months. (The 1971-2000 average is also for 16 months, i.e. January – December PLUS January – April). The areas mainly affected by drought (as the map below indicates) are the Midlands, East Anglia and South East, and rainfall levels since January 2011 are down by 19%, 18% and 15% respectively, but close to normal this year.
Figure 2
Figure 3
Forecast for May/June/July
The Met Office have also recently issued their 3 month outlook for May to July. For temperatures, they have this to say.
SUMMARY – TEMPERATURE: The balance of probability, both for May and the period May-June-July 2012, favours UK-averaged temperatures above the 1971-2000 climate mean, but in line with those observed over the last ten years. However, predictability for both periods tends to be low, with current forecasts indicating greater-than-average uncertainty in UK weather patterns as early as the beginning of May. May is also a month where there can still be large swings in temperature depending on the prevailing wind direction and so cold spells are still possible despite the most likely scenario being for above-normal temperatures. The probability that the UK-mean temperature for May-June-July will fall into the coldest of our five categories is less than 5%, whilst the probability that it will fall into the warmest of our five categories is around 45% (the 1971-2000 climatological probability for each of these categories is 20%).
http://www.metoffice.gov.uk/media/pdf/3/d/A3-layout-temp-MMJ.pdf
And precipitation.
SUMMARY – PRECIPITATION: For UK-average rainfall, the predicted probabilities slightly favour above normal values during both May and May-June-July. However, confidence in this prediction is not high, and there is still a significant probability of below normal rainfall. Whilst the wet weather of recent weeks will have had a positive effect on soil moisture, with all that that implies for agriculture, it is unlikely to have had a significant impact on groundwater supplies. With the forecast for May and May-June-July not favouring a continuation of the current very wet spell, groundwater resources in southern, eastern and central England are very unlikely to recover during this period. The probability that UK-average rainfall for May-June-July will fall into the driest of our five categories is around 15%, whilst the probability that it will fall into the wettest of our five categories is around 30% (the 1971-2000 climatological probability for each of these categories is 20%).
http://www.metoffice.gov.uk/media/pdf/2/l/A3-layout-precip-MJJ.pdf
In other words, it will probably be hot and wet, but they don’t really know. Maybe, Robert Napier should go back to saving polar bears.
The met office should be paid on a performance basis. Only pay them when they get it right.
I live in East Anglia, one of the areas of the UK now officially ‘in drought’. We’ve just had the wettest April for 100 years here and according to the Met Office weather reporter on BBC ‘Look East’ (the local BBC News) it rained at least once on every single day of April to some degree. We’ve had entire caravan sites evacuated, flooding in many places, many sporting and other events are even now cancelled due to waterlogged land (it’s a holiday weekend here in the UK), yet the BBC doggedly maintains that the recent record downpours ‘do little to alleviate the ongoing drought’ due to something called ‘groundwater run-off’. The hosepipe ban remains in place.
Oh, and by the way 2+2=5.
I had over 120mm of rain in the last two weeks alone (in Bedfordshire, Midlands).
Just as an illustration how clueless some people are: there’s a new town being planned North of Cambridge. The location along the river Cam is called “Water Meadow”. Locals will tell you that in wet times, that’s now, the place is soaked. It is. Yet the shire council happily gave the go-ahead, when it was not so wet, obviously. Clearly they think the future’s dry.
DaveS says:
May 5, 2012 at 10:54 am
Will the Met Office now be pleading for a bigger, shinier, computer to improve ‘accuracy’ of their forecasts?
Dave, they already have and the really, really stupid english Politicians have granted them double the last one £60m which I think is only 3 years in operation.
If I was paying my taxes in england my MP would be hearing from me in no uncertain terms.
diogenes says:
May 5, 2012 at 11:02 am
guys – I would be more worried about whether the water companies and the regulator rely on these forecasts when drawing up their budgets and forecasts
Too late, they do. They had a big sommet in march to discuss the drought with the UK MO, Water agencies, environmental agencies, Greepeace, WWF, FoE etc and declared a drought for the foreseeable future and hosepipe ban. Et Voilà, within a week it was pouring of rain and did not stop until now.
yet the BBC doggedly maintains that the recent record downpours ‘do little to alleviate the ongoing drought’ due to something called ‘groundwater run-off’. The hosepipe ban remains in place.
This was “the ground is hard dry and therefore the water was running off into the rivers. They forgot that it had been raining for thte last month and the ground was saturated and that was why the water was running off. What was even more stupid of the BBC was them looking down a borehole and suggesting it was low and therefore there was still a drought. The half-wits do not understand that it takes a measurable amount of time for the ground water to reach the nap.
Wow, I missed most of May, and June altogether!
Paul coombes says:
May 5, 2012 at 10:01 am
Definition of drought in the UK used to be 3 weeks without rain when I lived there.
There is an old saying in the UK, which, I am sure, predates the Met. office.
Oak before ash, we’re in for a splash
Ash before oak, we’re in for a soak.
Anyone from the UK know which came into leaf first; ash or oak?
A similar view to Phil Ford’s from here in the drought-stricken SE. It must be that the Met/ BBC, relying as ever on their favorite model data, haven’t thought to venture out with a flood guage. At least the hose-pipe ban is not proving very onerous…the garden is looking nice and soggy with no help from us.
Huh?
everyone who works with a weather forecast accepts that it is not deterministic.
They issued a probabilistic forecast. That forecast included low probabilities for
both wetter and cooler.
I roll two dice: I predict the sum will be 7, but I note that the sum could be 2 or 12.
you roll snake eyes. My prediction isnt wrong.
One cannot both believe that the weather is chaotic on short time scales AND criticize probablistic estimates that recognize this fact.
I wonder what they use as a basis for forecasting at the Met office? Hasnt anyone noticed that in the last three years in spring high pressure over the North Atlantic and Asia has blocked low pressures or changed their route over the UK? Thus also dumping arctic air (=cold) over NW Europe/ North Sea for extended periods? In which case of course its (very) cold and wet….
But the real question is, why has the North Atlantic high pressure situation changed? Whats up with that?
Problem is, Thames water have sold off about 20 reservoir sites and were also refused permission to build a new one in the Didcot area, being told to fix all their leaks first as they are under-performing in that area. Caroline Spelman is I believe one of those who opposed the new reservoir which will be required anyway because of immigration in the South East.
As I recall, Essex and Suffolk are classified as semi-arid with rainfall less than many deserts.
DaveE.
Hang on, a new prediction from the MET has arrived – apparently Saturday and Sunday will fall on the weekend next week. Just leave the money under the front doormat.
Carrie, you are not updated. You have no idea about how much a crystal balls costs these days! I am convinced that MetOffice made a vice choice to take the next best technique to but a fraction of the cost.
Steven Mosher says:
May 5, 2012 at 12:05 pm
“One cannot both believe that the weather is chaotic on short time scales AND criticize probablistic estimates that recognize this fact.”
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Probabilistic estimates deserve criticism because they are essentially worthless.
The truth is that short-term weather can be forecast with reasonable accuracy 4-5 days in advance, beyond that it is guesswork.
All meteorological organisations should simply acknowledge that inconvenient truth instead of spinning a whole load of gobblededook designed to give the impression that they know a lot more than they actually do……
I’m sure they(Met Office) will provide themselves a big bonus on their ‘accurate’ forecasts…
@Mosh
everyone who works with a weather forecast accepts that it is not deterministic.
They issued a probabilistic forecast. That forecast included low probabilities for
both wetter and cooler.
In other words, it’s all a bit of a waste of time>
Compared to other weather forecasters the Met Office has low skill. Its record is appalling, so much so they had to abandon long range seasonal forecasts.
One of our local radio stations has a fun feature called “five word weather” after the news bulletins.
One day last week it was “Drought ? shower in the garden”
It has intrigued me for years how climate scientist can be convinced that history is wrong, have 20/20 vision of the future. but remain at a total loss about the present.
How does the UK, with 2,000 years of history, only have precip records back to 1910, or am I missing something??
Also, read this in the local paper in South Carolina. Seems the MSM is getting a good chuckle out of this as well. Britain endures damp drought!!
http://www.islandpacket.com/2012/05/04/2058667/its-raining-again-britain-endures.html
Yes, the easy headline is coldest since 1989, which was also the last year in CET max that April was colder than March. But here’s the real kicker in the figures.
If you omit April 30th – OK that’s cherry picking but it is the last day of the month and would have been May 1st if this were not a leap year – well, that day was over 4degC higher than the rest of April. So, these other days, max 12.7degC, were a colder max than any April in the whole CET record, stretching back to 1878.
So there!
Rich.
Anything is possible says:
The truth is that short-term weather can be forecast with reasonable accuracy 4-5 days in advance, beyond that it is guesswork.
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I probably agree but with reservations, there is one area of weather reporting/prediction where the MO excels. In the UK it is known as the “Shipping Forecast” and for a very good reasons it is updated 4 times a day.
When “those in peril on the sea” are happy to rely on a UKMO 4 or 5 day punt, then maybe I will start paying attention.
I suggest that if you were to ask the MO why 6 hourly updates are needed you would get an insight into their true confidence levels.
http://www.metoffice.gov.uk/weather/marine/shipping_forecast.html#All~All
Their prediction reminds me of Danny Gallivan in the old days of hockey commentary. “A scintillating blast – that went ten feet wide.”
In an ideal world the head of the Met Office would be giving an interview in the pouring rain on why this technically is a drought. And then the bus with the famous advertisement rolls by splashing water all over his Hunters.