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Monday, 2 July 2012

September 2012 forecast: heatwave for England

How hard is it to produce a long-range weather forecast? Evidently, it is not easy, as the following forecast posted by the Met Office for April to June on 23 March this year illustrates (you may need to pinch yourself after reading it):
The forecast for average UK rainfall slightly favours drier than average conditions for April May June as a whole, and also favours April being the driest of the 3 months.
As many of you will be aware, today the Met Office released its provisional rainfall figures for April-June, and rather than being drier than average, it has been the wettest 3-month period on record. Across the country double the average rainfall fell in June, making it the wettest for the UK as a whole, and the second wettest for England, where it was beaten by the disastrous year that seemed to have no summer - 2007.

It has been chilly too, with June proving to be the coolest since 1991. Whereas it has been an excellent few months for slugs and ducks, it has not been good for tourism at home. The miserable run of weather will doubtless have given a boost to travel firms selling a holiday in the sun, for it looks set to continue. On 20 June the Met Office issued a 3-month forecast for July-September 2012 which, to be frank, is worthless:
The probability that UK precipitation for July-August-September will fall into the driest of our five categories is around 20% whilst the probability that it will fall into the wettest of our five categories is also around 20% (the 1971-2000 climatological probability for each of these categories is 20%).
In other words, the Met Office is saying that there is a one in five chance that the amount of rainfall we receive will fall into one of five quintiles. Yes, that is true, but it does not constitute a forecast, being as it is a mere statement of raw probability. It tells us nothing, and as such is to all intents and purposes utterly useless. Given the embarrassingly wide of the mark Met Office long-range weather outlook and the fact that many seem to swear by the ‘accuracy’ of independent weather prophet Piers Corbyn despite his frequent gaffes (the winter of 2011-2012 was supposed to be another extremely cold one for us apparently, but as you will recall, it was warmer than average), I thought that I’d have a crack at forecasting myself and see if I can do any worse. If Corbyn can make a living out of it, why can’t I? As to my methodology, it is quite straightforward: a wild stab in the dark. Here follows the forecast for the rest of this summer and autumn (I take no responsibility for its accuracy, inaccuracy or sheer irrelevance, so make sure that you have some sunblock at the ready just in case my guesswork turns out to be somewhat wide of the mark).

Not overly good with plenty of rain. Slugs will continue to thrive and it will be at least slightly warmer than June as it couldn’t get any cooler. There will be marginally more sunshine for the same reason. A poor month for gardeners, a good month for mildew and a delight for extreme campers.
Update 5 July: Piers Corbyn's July forecast has gone live, and it looks like he agrees with me when it comes to anticipating a forthcoming paradise for slugs at home. Well done Piers! Good to see you catching up with my random weather forecasting approach. In his own inimitable style Corbyn predicts 'A July of dramatic contrasts and likely record-level extremes. "Off-scale" rain, thunder-floods, giant hail, gales and tornado damage likely in NW Europe.' Now, you could never accuse him of overdramatising or using tabloid language could you? For some reason, use of a term such as "thunder-floods" brings to mind Native American linguistic usage. Maybe Piers is part Cherokee, part Nostradamus?

Better than July and probably a little warmer and drier. Slugs will still be doing well, and half of what is in your vegetable garden will probably be stunted, rotten or both. Those potatoes that have survived will be massive. If you live in the South, you will have plenty of green tomatoes for making chutney. If you are a parent, your school-age children will by now have driven you half insane and bankrupted you through repeated demands to get involved in diverting activities that involve parting with large sums of cash.

The best month of the ‘summer’ with an extended dry spell and an unseasonable heatwave of at least a week in duration. If you’re planning a holiday in England, this will be the month during which to enjoy it. If you’ve booked yourself a trip overseas, you’ll be cursing yourself for having missed the good weather at home. Meanwhile, the national press suffers an outbreak of predictable headlines incorporating the word ‘scorcher’ and the phrase ‘warmer than’ many places which are known to be hot. New record low for Arctic sea ice reported.

Not a bad month. An Indian summer and dry overall. Warm. Piers Corbyn issues the first version of his winter forecast intimating that it will be “unusually cold” in line with his reissued prediction of an impending ice age. Details relating to “an exceptionally cold surge of Arctic air” will be made available to subscribers to his long-range forecasts for a very reasonable fee equivalent to a pensioner’s winter fuel payment. First forecasts of a white Christmas appear in the press, together with bookies' odds.

A wet, windy and generally mild return to slug heaven. Eric Olthwaite would be delighted. Given the surfeit of slugs this year, you will be left puzzling as to why hedgehog numbers are still declining.

Mild, overcast and damp. The possibility of some sleet in the Scottish Highlands. By this point, the resident Chinese population has decided to change the designation of 2012 from 'Year of the Dragon' to 'Year of the Slug'.

Don't laugh, as you'll probably see this post being quoted by the Daily Express in months to come as a genuine long-term forecast. The following may also be of interest: Winter 2012-2013 Weather Forecast: will Arctic Sea Ice Cover play a Role?


  1. If people are not happy with that, they can mix the forecasts about, I'm sure it won't make a lot of difference.

    1. I'm sure they'll be delighted come October Juniper, by which time I hope to be providing lucrative weather forecasts for the big supermarkets. Then again, perhaps that won't be the case.

  2. Replies
    1. I had to 'channel' to spirit of Foggitt with the above Cygnus. His presence was strong. However, I've never attempted to forecast the weather through reference to moles (the sort that you find in the ground, rather than on bodies or in ports) as he did. Maybe, you could try a forecast based upon the presence or absence of that rogue goat that you mentioned once made it into your garden?

  3. I can't believe the Met Office continue to get away with this. They demostrate, time after time, that their ability to forecast weather beyond a few days, is hopeless.

    I thought that the way their March predictions for April May june turned out were very amusing - but the July August September probabilities are, in a way, even more fun!

    If I understand correctly, we start with a spread of 5 quintiles of probability outcomes. In essence, these are very dry, quite dry, average, quite wet and very wet.

    Without any sense of irony or embarassment, they pronounce that there is a 20% chance of it being drier than average - and a 20% chance that it will be wetter than average.

    Wow! That is as much use as a chocolate teapot!

    Again, without any sense of irony, they write that these predictions are made using "Observation, numerical computer models and experts". WTF! If, as a result of all their "observation, numerical computer modelling and expert input" all they can come up with is that it might be drier or wetter than average,and there is an equal chance of both eventualities, then, for heaven's sake, can't they just admit they haven't got a clue. The roll of a 5 sided dice is likely to be just as acurate.

    The serious point in all this is that these same "observations, computer models and experts" are the ones telling us what is going to happen to global temperatures.

    Amazingly, if we have doubts about their accuracy to tell us what is going to happen over the next 100 years we are branded "deniers".

    At what point does someone in the Met Office actually start to question their models and investigate possible in built bias that is making them look like idiots - on a very regular basis (BBQ Summers, Mild winters, etc).

    1. Perhaps you've hit upon the reality of the Met Office supercomputer: a five-sided dice. Their current three-monthly forecast is the worst that I've ever seen and, as you note, is utterly worthless.

      Although the Met Office is now generally pretty accurate with its forecasts up to five days in advance, longer-range predictions are hopeless. Meteorology is still in its infancy, and the complexities of climatology have yet to be unravelled too.

  4. Tis right damp ere and has been spitting fer most if not all the heck, it`s right grand!

    1. Aye, 'tis that, but 'twere neither micklin' nor mucklin' for much ot' weekend.

  5. Love this forecast, especially as I am on holiday in September. When you get to the prediction for Cornwall in June 2013 please made that a good one too.

  6. Nice to hear a bit of good news our pet slugs are delighted. Damply optamistic Tavistock

    1. Your slugs are privileged to live in such a delightful part of the country. Remember to keep them in rude health by feeding them plenty of their favourite food: salt.

  7. Umm, what makes you think you can forecast weather better than the met office??

    1. Adam, have you not heard of the phrase "tongue in cheek"? My 'forecast' is intended to be a piece of humour, nothing more.

  8. Keep up the good work, though my garden has been digested by a plague of slugs and snails I have been comforted by the met office forecast. I have now packed the car with what is required for safety for the family
    Suncream,swim ware ,blankets,umbrella,snow shovel,antifreeze,flasks of hot tea,sunglasses,rain ware,down jackets,sleeping bags,ice cream,water,gloves,snow chains ............. that should get us to the supermarket this morning.

    1. It may console you slightly to learn that what little I did plant this year has been entirely consumed by slugs. I too, face domestic famine.

      Congratulations on making such comprehensive preparations for all meteorological eventualities! That reminds me: I must purchase some sunblock and gloves.


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