The European Monsoon is a recognisable trend, whereby the prevailing westerly winds from the Atlantic, which weaken at the end of Spring, pick up again at the beginning of June and bring with them wave after wave of rain-laden depressions that can last into July.

This has actually been a noted phenomenon for nearly a century, and is referred to as the "Return of the Westerlies" by meteorologists. No one seems to agree why it occurs - according to meteorologist Philip Eden, possible contributing factors include the retreat of snow and ice from northern Canada and the shift of the subtropical jet stream over Asia - but records suggest that, on average, it happens in seven out of every 10 years.

From: The question: What is the European monsoon? | Weather | The Guardian

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Hold the barbecues and reach for your umbrellas — Britain’s monsoon season has begun. It even snowed over the hills of Cumbria and Northumberland on Friday, before the washout over much of England and Wales this weekend with some atrocious downpours, flash floods, thunder and lightning.

The outlook for the rest of this week is for more bouts of thunder and heavy rain, with interludes of sunshine. So what happened to the Met Office’s bullish forecast of a barbecue summer, with glorious sunshine and scorching temperatures?

The beginning of June in Britain is almost always like this thanks to the European monsoon. This strange glitch in the weather sweeps rain across much of northwestern Europe, but is very different from the bigger and wetter Indian monsoon, which is driven by the ferocious heat of the Indian sub-continent sucking in cooler, moist air from the sea.

Our monsoon is brought on by a resurgence of westerly winds from the Atlantic, where they become loaded with wind and rain. Usually these westerly winds slacken off during spring, as the high-altitude jet stream eases off and brings a respite from the Atlantic depressions. But as regular as clockwork the westerlies pick up again in June, which is why this phenomenon is also called “the return of the westerlies”. The rain usually arrives in two waves, at the beginning of June and again in mid to late June, when the downpours often play havoc at Wimbledon and can turn the Glastonbury Festival into a mudbath.

But there is still hope for the rest of our summer — the European monsoon usually fizzles out by the start of July, and after that there is plenty of time for the Met Office’s sunny forecast to come true.

From: "European Monsoon" to blame for cold and rainy start to June - Times Online

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Ok this is strange because last year when we had a wet summer they said it was caused by the El Nina now this year their saying it's the westerly winds from the Atlantic but we all know this it's happen's all the time so the way I see it is they dont have a clue to what's realy going on and at the same time it's also funny because it goes to show how little we understand of the weather.

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The European Monsoon occurs pretty much every year at the end of May and beginning of June. Even the hottest summers have experience the monsoon period at this time of year. The question is how quickly the Jet Stream can recover and head north, because the past 2 years it has stayed too far south after the 'monsoon' period. Here's hoping it goes north which it usually does.
El Nino, La Nina or not, it will always be due to westerly winds

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It would be nice if it went north for a while then to gain some heat from the sun to create more storm's (if Im correct).

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Are there any useful web charts which show the current placement of the jet stream and which give reliable forecasts?

Thanks

John

You can find a chart for the jet stream on Wunderground

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