Temperatures are likely to be below average this weekend and through next week. Although we have had short-lived cold snaps in December and earlier in January lasting 2 or 3 days,  it would be fair to say that this period of cold weather is likely to be the most prolonged we have seen so far this winter.

At the moment we have a high pressure system over eastern Europe trying to push in cold air from the east, while milder Atlantic air is trying to push in from the west. The colder air is set to win over the next few days, bringing a risk of snow to western areas on Monday morning. Higher parts of Wales and north-western Britain are most at risk, although exactly where and how much snow there will be is still in the balance and you should stay in touch with the latest forecasts and warnings on our website.

Forecast pressure chart for 00:00GMT on Monday 30 January

Later on Monday the weather front weakens and moves back west, leaving drier conditions for the UK with a few wintry showers possible in the east at times.

As we go into February there is still considerable uncertainty in the forecast, although at the moment we expect the cold weather to persist with occasional wintry showers near to the east coast and sharp overnight frosts. Although temperatures will be below average, it is not expected to be exceptionally cold.  Alternatively by the middle of February we could see a return to milder and more unsettled conditions with showers or longer spells of rain.

With the colder conditions, the Met Office will be issuing Cold Weather Alerts as part of the  Cold Weather Plan developed by the Department of Health, the Health Protection Agency and Age UK to help reduce the impact of cold weather on people’s health this winter.

Age UK demonstrates just how valuable the Cold Weather Alert Service is to the more vulnerable sectors of the community. These alerts put everyone in a better position to respond to forecasts of severe weather, inform those who are most at risk from winter weather and what they can do to keep well.

For more info on the latest weather forecast you should go to the Met Office website.

The Met Office contributed to the CCRA providing scientific guidance on the latest climate projections (UKCP09) and leading the risk assessment on the energy sector. In addition we also provided further research on urban heat islands and rainfall runoff. Utility Week have also covered the launch of the study, reporting on how ‘Utilities face some of the heaviest threats from global warning, a comprehensive government study shows’.

Elsewhere there was widespread coverage about the launch of our new Met Office Android App as it made ‘app of the day’ on TechDigest. At the same time we also launched an update to our iPhone App. Bothof these were covered in the Guardian as well as on android authority and intomobile.

This is because the atmosphere is currently in a finely balanced state and, depending on which way it goes, this could lead to a continuation of milder weather or a switch to much colder conditions – with frosts, ice and snow possible.

It comes down to whether we’ll continue to see the current pattern of westerly winds bringing in milder conditions from the Atlantic, or whether a high pressure system developing over Russia will extend towards the UK to bring in cold air on easterly winds.

The Met Office and forecast centres around the world have been studying this situation closely but the 50/50 split on which outcome is the most likely has persisted – until now.

It now looks as if the scenario for colder conditions is slightly more likely, but our forecasters stress that a lot of uncertainty remains and milder weather could return.

Looking at our current forecast for the end of next week, our guidance states: “…a general continuation of the cold weather type seems most likely, but it is by no means certain. There is a risk of snow, ice and sharp frosts, with easternmost parts being most prone. However we certainly cannot discount the possibility that mild west/southwesterly winds will return instead, bringing rain at times.”

Looking further ahead, the forecast for mid-February onwards remains very uncertain too. Looking at our current guidance, it states: “…the most likely outcome is for much colder weather with winds mainly from an easterly quadrant to prevail, bringing widespread frosts, and snow to some areas. In this scenario it would be the east that would be most vulnerable to snowfall. There remains an alternative scenario, in which milder westerly winds prevail, the chances of this alternative scenario are currently rated as about one in three.”

Our forecasters will continue to closely monitor the situation, so for the latest information check our weather forecasts and warnings about what to expect.

Guest blog: Sarah Reay, British Geological Survey

Many people in the UK were treated to a fine display of the northern lights (aurora borealis) on Sunday night. This was seen widely throughout Scotland and the north of England. There is a chance for further auroral displays tonight or tomorrow night if we are lucky.

The Northern Lights are a result of a geomagnetic storm. These storms are short-lived periods of high geomagnetic activity where the Earth’s magnetic field changes very quickly and strong electric currents flow high in the atmosphere.

The geomagnetic storm is a consequence of activity on the surface of the Sun. Occasionally there are large explosions on the Sun, and huge amounts of charged particles are thrown out into space. These particles sometimes travel towards Earth where they are captured by the Earth’s magnetic field and guided towards the geomagnetic polar regions. On their way down these particles are slowed down by Earth’s atmosphere, which acts as a shield. These charged particles collide with gas molecules in the atmosphere. The energy released in these collisions is given off as light.

Geomagnetic storms follow the 11-year solar cycle. As we are heading towards the next solar maximum, due in 2013, the chance of big magnetic storms is on the increase. On average you might expect to see aurora in the far north of Scotland every few months, but less often as you travel further south.

To view the Northern Lights you are best finding a dark place away from street lights. You will need a cloud-free sky. In general, look to the north although it could be overhead or elsewhere. For your best chance of sighting an aurora, try to look during the hours around local midnight (22:00-02:00). However geomagnetic activity can happen at any time!

You can sign-up to receive alerts from the British Geological Survey when there is a chance for aurora activity. Unfortunately cloud is predicted for most of the UK tonight, but there is a much better chance for Wednesday night onwards. Keep an eye on the Met Office forecasts for the latest information.

* Many thanks to Sarah Reay of the British Geological Survey for the above guest blog. As a side note, people may be interested to know that solar storms can have other impacts on our planet – such as affecting telecommunication systems. The Met Office is developing a space weather forecasting system to give early warnings of events. As part of this, we are working in collaboration with the US’s National Oceanic and Atmospheric Administration (NOAA) to develop the service.

Following the success of the Met Office weather app on the iPhone, weather forecasts from the Met Office are now available for Android. The app can be used on all android phones and includes a widget so information can be accessed directly from the dashboard.

Key features of the new android app include:

• Free to download
• Up to date weather forecasts and warnings from the Met Office
• At a glance five day overview
• Three-hourly location forecasts
• 5000 locations to choose from with multiple favourites.

You can download the app from the Android Marketplace.

The Android app is the latest addition to our offering for mobile users, complementing our existing products; Mobile Weather for feature phone users, Smarter Weather for smartphone users and the iPhone app for iPhone users.

A new updated version of the Met Office iPhone app is also now available, taking into account the feedback we have received on the original version.  New features include three-hourly forecasts available up to five days ahead, UV forecast maps and information on the likelihood of rain or snow.

The iPhone app is available in the Apple App Store.

The correction, printed on page 2 of the paper, and is reproduced below:

The Met Office

Following “Outlook fair for amateurs as Met Office releases data” (Nov 27), we are happy to make clear that, as noted by the Select Committee for Transport, the Met Office did warn the public of last winter’s cold weather from early November 2010 and that it did accurately forecast the weather in London on the day of the Royal Wedding. While the Committee questioned the usefulness of Met Office seasonal predictions, it accepted the accuracy of its short-term forecasts.

Following the publication of a scientific study on the effects of changes in solar output on climate change several papers reported on the findings that although solar output is likely to reduce over the next 90 years this will not substantially delay expected increases in global temperatures caused by greenhouse gases. The Daily Telegraph reported ‘Solar slump will not slow climate change’, whilst Reuters reported ‘Weaker sun will not delay global warming‘ and the Guardian said ‘Sun’s changes unlikely to slow global warming’.

Elsewhere there has been continued interest in the changeable weather affecting the UK at the moment. For the most up to date information check out our latest weather forecasts online.

The number of plays exceeded initial expectations and demonstrated the benefits of obtaining user feedback in this way. Thank you to all that took part and played the game – we could not have done this without your help.

The weather game received positive press coverage nationally and also from around the world after becoming the largest study on the understanding of probabilistic weather forecasts undertaken. The Washington Post reported on how game players were contributing to the science of communicating uncertainty in weather forecasting, whilst Digital River reviewed the game, reporting: “The efficacy of a well-designed ‘gamification’ strategy has been demonstrated brilliantly by the Met Office in this case.”

Analysis is still ongoing but results so far have shown some interesting findings. Key results include:

• When faced with straightforward decisions, providing probabilities doesn’t confuse people.
• For more complex situations, on average people are able to make better decisions using probabilities.
• People make the best decisions when more detailed information on forecast uncertainty is provided.

With such a large dataset these results only represent the tip of the iceberg. The data is still being analysed and the intention is for the full set of results to be published in peer reviewed journals. We will let you know when the articles are published and will make the underlying dataset available online. This could be of use for school or university projects – we would be interested in your findings. Thank you again for taking part.

Related articles

• A busy year for the Met Office in 2011 (metofficenews.wordpress.com)
• Communicating uncertain forecasts (metofficenews.wordpress.com)

The outlook for this period is finely balanced, with two scenarios looking equally possible: the first being a continuation of the changeable and relatively mild conditions we’ve seen so far this winter; the second being a shift to a period of much colder weather.

Whilst two different outcomes are possible, it does look as though the general pattern that establishes itself by the start of February could last for quite a while, perhaps even until the middle of the month.

However, it is not possible to say which of the two scenarios is more likely due to an unusual amount of uncertainty in the forecast.

For these longer range outlooks, we use sophisticated techniques to understand the uncertainties – called ensemble forecasts.

In an ensemble forecast we run a forecast model many times from very slightly different starting conditions. The range of different outcomes gives us a measure of how confident or uncertain we should be in the overall forecast.

Currently the ensembles for the start of February onwards show a fairly even split that does not clearly favour either the mild or the cold option – and there are relatively few solutions in between.

There is a possible explanation for this relatively rare situation. In recent days there has been an increase in temperatures in the high atmosphere (the stratosphere) over the northern hemisphere. This change seems to have been driven in part by marked changes in the weather patterns lower down in the atmosphere – over the north Pacific for example.

Research, developed in part by the Met Office, suggests that changes such as this high up in our atmosphere can – in time – go on to affect weather patterns at surface-level. However, this is a new and very complex area of meteorology where we are still developing our understanding of all the mechanisms involved.

It is possible this is why we are seeing the volatility in the current forecast, as different model runs handle the interactions differently.

Rest assured, whatever happens we’ll keep you up to date with the latest information through our forecasts and weather warnings – so as soon as we know, you’ll know.

Looking at January, half-month figures show it has been a mild start to 2012 – with UK mean temperatures 2.1 °C above average.

This gives a mean (including night-time and day-time temperatures) of 5.5 °C, which – if it stayed the same – would place it as one of the warmer January’s in climate records which go back to 1910.

However, we have to be very cautious about using half-monthly statistics as they don’t really tell us much – things can change dramatically in the second half of a month so it is far too early to make any judgements.

December was a slightly milder than average month, but at just 0.6 °C above the UK long-term average for mean temperatures it wasn’t that remarkable. If you combine those with the half month figures for January, the winter so far has been milder than average.

Like the half-monthly figures, however, it’s far too early to say how this winter as a whole will fare in the records as (meteorologically speaking) we are only half way through – with the rest of January and all of February to go.

Traditionally these are the colder months of the winter, and with more changeable conditions in the forecast it’s difficult to say how mild, cold or average this season may end up.

Looking in more detail at January’s half-month statistics, other points of interest are that sunshine is slightly ahead of where we would expect – with the UK clocking up 68% of the usual sunshine for the whole month in the first 15 days.

The sunniest region has been England, with 75% of its average January sunshine hours so far. The least sunny region, Northern Ireland, has had 52% of its average for the month – about ‘on schedule’ at this point.

Rainfall has seen a more mixed picture, with England having just 37% of the average so far and Scotland being slightly ahead of schedule at 59%.

We will have to see how the second half of the month, and the season, affects the final figures before we can assess how the month and season place in the rankings.

To help with observing clouds we’ve created this infographic. Feel free to share and use on your own website or blog, you can get the embed code and a printable version from our cloud spotting page.

Source: metoffice.gov.uk

If you spot any interesting clouds, why not take a picture and add them to our Flickr clouds group.