Archives for August 2009

So, that's Summer 2009 over.At least, in so far as Met Office statistics are concerned.

Of course, in reality, most of the public - let alone thousands of hoteliers, beachfront café owners, ice cream vendors and others - will be rather hopeful of our 'Summer' continuing to bring spells of warm, settled weather into September.

For meteorological purposes however, summer spans June, July and August.And inevitably, it's a period when our weather forecast accuracy comes under considerable scrutiny, with little room for forgiveness when things go badly awry.

In fairness, this happens rather infrequently. Public perception and media profile of 'bad' forecasts are inevitably outweighed, proportionately, by the far greater number of correct forecasts we give using Met Office data - but inevitably, these success stories receive little or no publicity. Bad forecasts, after all, make great news. 

So for forecasters, Summer 2009 has been a season of considerable pressures and expectations. After all, we deserved a good summer in 2009, didn't we?Especially after the abysmal weather we endured through the drenched summer of 2007 and the record-breakingly dull version experienced in 2008.

And Lo, a glorious summer was duly forecast.

Or to be more accurate, it was duly reported, with various, ah, 'embellishments'.

The most cited embellishment of all - Odds-on for a Barbecue Summer - was admittedly the Met Office's own creation. After some excellent and highly accurate winter forecasting effort throughout the major snow events of February, 2009 risked becoming an Annus Horribilis for the Met Office by the end of July, as - beneath repeatedly inclement weather that month - the upbeat summer forecast seemed to be falling apart at the seams.

But rather lost in the media backlash, the reality - statistically speaking - is that we've actually enjoyed a fairly reasonable three months.Fairly.

June, let us recall, was regularly glorious and often very warm. Indeed for some regions, the weather brought heatwave conditions, while the new high-tech

July, however, was the spoiler. As the jet stream snaked southwards, steering Atlantic cyclones towards the British Isles and surpressing any meaningful extension into NW Europe by the Azores High, we started to see conditions which had been all-too-familiar the preceding two years - bringing often persistent cloudy, wet and breezy weather.

Indeed, here in the West Country, July's rainfall for some areas - notably Bristol - gave the highest tally recorded since 1888; a whopping 162.1mm, as noted by local amateur meteorologist Barry Horton whose exhaustive historical statistics are presented on his excellent website. Barry also notes, in terms of Bristol's temperature through July 2009, that:

... this is the 3rd consecutive July when temperatures have been below the 30 year average for the city....0.2°C below the 30 year average of 17.8°C.

We're awaiting the final August statistics, but it's not been a dreadful month by any means; albeit as the Polar jet stream continued to snake close at hand, changeable weather has largely dominated. Just last week, the remnants of Hurricane Bill - completing it's extra-tropical migration into oblivion across cooler North Atlantic waters - brought us wet, windy but noticeably mild weather across the country.

Was the summer long range forecast really such a disaster? For the scientists who are pioneering this type of largely experimental work, it was arguably was never intended for wider consumption as an 'operational' public forecast.After all, the original long-range seasonal prediction - of an "average British summer" - had talked merely in bland terms of "less than average" rainfall and "average or warmer-than-average" temperatures.

The evocative term "Barbeque Summer" was a lurking PR banana-skin likely to compromise scientific credibility in the event of things going horribly askew. Consequently - and faced with a changeable August forecast - the Met Office was understandably adopting a cautious tone by the end of July, with only a month of summer was left to match the media hyperbole and inflated public expectations.

So, we march on to Autumn and to Winter. And the early, indicative seasonal prediction from the Met Office provides an early hint of what to expect, weather-wise, for the coming winter: essentially wet and mild. Read it from the Met Office here and you'll find further updates will follow in the coming weeks.

Certainly an interesting few months lie ahead, not least as we look to the distant waters of the central South Pacific, where an ENSO (El Nino Southern Oscillation) oceanic warming event is already well underway, bringing the potential for some profound but poorly understood influences across various aspects of global climate. Many of these are expected to herald distinctly unwelcome, even life-threatening weather across parts of the developing and impoverished world, making our mutterings over a not-so-barbeque summer seem utterly trivial by comparison.