August weather summary

11 09 2013

Overall August saw quiet weather, with temperatures close to average. Forecaster Helen talks through the weather we saw in August in our summary video.

A maximum temperature of 34.1 °C was recorded at Heathrow on the 1st, the highest UK temperature since July 2006. A minimum temperature of 0.2 °C was recorded at Kinbrace (Sutherland) on the 5th. In the 24 hours ending at 0900 GMT on the 5th, 61.0 mm of rain fell at Porthmadog (Gwynedd). A wind gusts of 68 mph was recorded at Needles Old Battery (Isle of Wight) on the 17th. Visit our climate section for a full written summary of the month.

Your pictures

Thank you for sharing your pictures of August weather with us on Twitter, here’s a few of our favourites…





August Bank Holiday weather extremes

23 08 2013

The August Bank Holiday is always the last Monday in August, although these statistics include Saturday and Sunday, to look at the whole weekend. At this time of year it can still be quite hot, although there have been few instances of this actually being the case over the Bank Holiday weekend itself. In some years the progression of Atlantic low-pressure systems have arrived by the end of August, bringing wind and rain.

Here are the warmest, coldest, wettest and windiest August Bank Holiday weekends, as provided by the Met Office National Climate Information Centre.

Warmest

Temperatures reached 31.6 °C at London Weather Centre on Saturday 25 August 2001, and more than twenty stations exceeded 30 °C on that day, mostly in the south-east and East Anglia. Saturday 25th August 1990 was also very warm in many parts.

Coldest

Numerous Scottish stations failed to get above 10 °C on Sunday 28th August 2011, the lowest maximum being 9.1 °C at Cromdale. This excludes stations 500 metres above sea level, which may be considerably colder.

There have also been numerous instances of air frost over the August Bank Holiday, most of them in Scotland, most notably in 1977 and 1982. The lowest individual reading was -3.1 °C at Kindrogan on Sunday 28 August 1977.

Wettest

On occasions 100 mm or more of rainfall has been recorded in a day. The highest 0900 GMT – 0900 GMT figure is 152.2 mm, recorded at Glendessary on Monday 31 August 1992. Widespread heavy rainfall also came from the remnants of Hurricane Charlie on Monday 25 August 1986.

Windiest

A maximum gust of 78 mph was reported at Lerwick on Monday 29 August 2005. Strong winds were also relatively widespread in 1986 and 1992.

Check your local Bank Holiday weather forecast on our website.





The jet stream and why it’s too early to write-off summer

13 05 2013

There have been one or two stories in the press today saying we’re in for another washout summer, which would rightly inspire collective misery across the country.

However, it’s a far too early to be writing off any chance of a decent summer season – after all, it doesn’t officially start (for us meteorologists) for more than two weeks (on 1 June).

It appears the news stories are borne out of the current position of the jet stream, a band of fast moving westerly winds high up in the atmosphere. But why is this important?

A quick Jet stream explainer

The jet stream tends to guide the generally wet and windy weather systems which come in off the Atlantic. So, if it’s over us or just to the south, we tend to get a lot of wet and windy weather – which is what we expect through winter.

If the jet is to the north of us, it guides that changeable weather to the north to give us more settled conditions – which is what we expect in the summer.

(You can read a bit more about the jet stream, how it impacted our weather last year, and any potential connections to climate change in a blog story we wrote last year).

What’s going on now?

Right now the jet stream is sitting to the south of the country and it is influencing the unsettled weather we are seeing at the moment.

Forecast chart showing position of the jet stream at midday on 13 May 2013

Forecast chart showing position of the jet stream at midday on 13 May 2013

It’s fair to say that this is roughly the position it was in for extended periods during the exceptionally wet weather that we saw last year, particularly in June.

Crucially, however, the jet stream does move around quite a bit and it can change its track significantly in just a few days. So the current position of the jet stream does not mean that it’s stuck in that position.

Looking ahead

Much like our weather, it’s a huge challenge to predict the exact track of the jet stream more than five or six days ahead, so there’s still a great deal to play for in the outlook for our summer.

In short, it’s far too early to write-off summer 2013 based on the current position of the jet stream.

To get the best information on what to expect you can see the latest detailed forecasts out to 5-days on our website, as well as a general view of what we expect out to 30 days.

You can find out more about the jet stream in our YouTube video.





Cold night breaks August records in places

31 08 2012

Last night saw some unusually cold August night-time temperatures across parts of the UK, with some observation sites hitting record lows.

Among those stations seeing their coldest recorded August temperature were:

Braemar No 2, Aberdeenshire: -2.4 °C

Aviemore, Highlands: -1.8 °C

Redesdale Camp, Northumberland: -0.7 °C

Bainbridge, North Yorkshire: 0.5 °C

Benson, Oxfordshire: 2.1 °C

Bradford, West Yorkshire: 2.8 °C

Observation sites have operated for differing amounts of time, so some records are more significant than others. Out of the new records, Bradford has the longest historical dataset – going back to 1908.

It’s worth noting that none of these break the all-time record low UK temperature for August, which is -4.5 °C recorded at Lagganlia, in Inverness-shire on 21 August 1973.

Why was it so cold in places?

Last night saw northerly winds drag cold air from quite a long way north over the UK. This air was also dry, which meant there was very little moisture to help retain heat from the day.

This, combined with clear skies caused by the high pressure sitting over the country, meant all the heat radiated into the sky – leaving very cold temperatures for the time of year.

Once in a blue moon?

While UK weather records such as this aren’t broken once in a blue moon (we’ve had many broken already this year), this set does more or less coincide with the astronomical phenomenon.

A blue moon occurs when there are two full moons in one month – which is perhaps not as rare as the saying may have us believe. There was a full moon at the start of August and now a full moon is due tonight.

You can read more about this in articles online, such as this one at earthsky.org








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