IMPORTANT NOTICE ABOUT BUZZ

Buzz is no longer available on the version of the app you currently have installed. This is due to changes in the way the page works.

To continue reading Buzz on your smartphone either:

1. Freely upgrade your app to the latest version available from the Google Play Store here [RECOMMENDED]:

   https://play.google.com/store/apps/details?id=com.two.app1
   

2. View Buzz on the TWO mobile web site here:

   http://www.theweatheroutlook.com/twoother/latest.aspx

TWO v1.1 for Android and IOS

TWO v1.1. will be a free download for Android from the Google Play Store from 20/01/2016. The app is also scheduled for release to iPhone / iPad. The new version of the app contains new functionality and usability improvements.

New functionality

There’s a brand new option to view forecast graphs for your selected location for the next 5, 10 or 16 days. These give you an at a glance view of forecast maximum and minimum temperatures, rainfall, mean and gust wind speed  and pressure forecasts. The graphs are responsive so when you flip your phone they expand to fill the screen.

As well as graphs a number of new charts have been made available including the stratosphere ones which have recently been added to the web site. You’ve also got direct access to 5 and 10 day aggregate charts showing rainfall totals, and maximum and minimum temperatures.

In addition there’s a great new option to toggle the charts to full screen mode. This displays the chart image full size meaning you can scroll around it. It doesn’t sound much but it massively improves the viewing experience over the existing app.

Formatting and usability

These alterations are more subtle and not immediately obvious. Changes to the colours used on the forecast pages have been made so they’re easier to read on lower contrast screens. Also the full page ads have been removed from this release. Hopefully this will please a number of you!

Summary

New functionality and improved usability make TWO v1.1 a significant upgrade for Android users. Ok, so what about the iPhone release? The app has been compiled for IOS and will be submitted to the Apple app store shortly and hopefully then made available for download.

High pressure next week?

A transition to milder and changeable conditions is still probable later this week. However, there is quite a lot of uncertainty about the details and high pressure may quickly return.

During the last 24 hours quite a lot of medium range computer model output has shown high pressure building and influencing the UK’s weather again next week. If this happens the key to our weather is where it becomes centred. The most likely option at the moment is over the south of the UK and this is where the highest likelihood of quite crisp and frosty weather is.  It’s not a given and if high pressure ends up farther east much of the UK could end up sitting under a breezy and very mild southwesterly airstream.

Are there other possible outcomes? This evening’s GEFS12z ensemble contains a few runs which bring much colder back towards the end of January. On the chart below about 7 or 8 of the individual runs bring 850hPa temperatures of between -5C and -10C in late January or early February. This is something to keep an eye on in the coming days.

Summary

Milder and more changeable weather is expected later this week. There is uncertainty  about the extent and duration of this transition. High pressure may be a player in the UK’s weather again next week and frosty conditions could return, particularly to the south. A much milder southwesterly can’t be ruled out, especially in more north western parts of the UK. Towards the end of the month there is a chance of cold air returning, although at the moment this isn’t the most likely outcome.

Chart viewer

Snow in the next 24 hours

A band of rain, sleet and snow will spread southeastwards this afternoon and tonight. Snow accumulations of several cms are possible down to low levels in places but the forecast details are uncertain.

The chart below is generated from this morning’s GFS6z run and shows where the rain, sleet and snow is forecast to be at midnight. By this time snow could be approaching the home counties and London and heavier bursts in the Midlands and north west may make for tricky driving conditions. Notice how on the western side of the precipitation rain is forecast and even at this stage there is uncertainty about its exact track and evolution.

The GEFS6z postage stamps below are valid for the same time. On these charts pink shading shows where snow is expected and rainfall is not plotted. (GEFS postage stamp charts showing rainfall are available on the Chart viewer). Each postage stamp displays the forecast from one of the GEFS6z runs and if you look closely it is evident quite a lot of variation in the track and intensity of the snow is still present.

Below is a chart from the Meteo France Arome model for 04GMT tomorrow morning. This uses a horizontal 0.025 degree grid, that makes its resolution almost 10x higher than the GFS which is currently is running at 0.2 degrees. As the model is run by Meteo France it is designed to provides forecasts for France, therefore the coverage only reaches as as far north as central England. Nonetheless, it’s extremely useful for London and the home counties!

The Arome and GFS data are both suggesting a covering of snow is likely in the home counties and possibly in London. In the Chilterns I’m quite confident of seeing several cms of snow by the morning  – I’ll Tweet (@TWOweather) a picture from Berkhamsted tomorrow morning proving me right or wrong!

Tomorrow morning the remnants of the wet weather should clear away to leave a dry and cold day. Temperatures above 0C (32F) will allow lying snow to thaw. During the second half of the day another band of rain is expected to push into the west and overnight and into Monday this may turn to sleet and snow in places as it pushes eastwards.

Summary

Parts of the UK can expect their first snow fall and lying snow of the winter in the next 24 hours. The north west, Midlands and parts of central southern England are at greatest risk. There is some uncertainty about the details and rain rather than snow is likely on the western side of the precipitation band. It could also fade overnight as it pushes southeastwards towards London and the home counties. However, if like me you live in this area don’t forget to take a look out your window tomorrow morning!

Chart view

Risk of snow increasing

The  weather prospects for the coming days are very uncertain. Computer models are jumping around showing different solutions but there is a risk of disruptive snow in parts of the UK. Forecast confidence is low partly part because of the development of Alex, the first January hurricane since 1938!

In the short term cold air will remain embedded over the UK. There are scattered wintry showers today but for most areas there is a lot of dry and bright weather. Unfortunately forecast confidence begins falling away as soon as tomorrow. After a cold and frosty start cloud builds from the west and during the afternoon it looks like rain, sleet and snow will spread into Northern Ireland and western parts of Britain.

Here’s the GFS6z view for 15GMT Saturday, 16th January.

On the GFS6z the precipitation is shown making slow progresses eastwards and decaying. The chart below is for 12:00GMT, Sunday 16th January.

So there is likely to be some snow around this weekend but don’t expect the charts I’ve posted above to be spot on. In fact they could be quite wide of the mark so check the local place or postcode forecasts and the snow charts which update on TWO every 6 hours.

By Monday more wet weather pushes in from the west and this has the potent to affect a bigger area. Again the details are subject to significant change. The chart below is from this morning’s run of the Meteo France Arpege model. This is a higher resolution model than the GFS and so should be able to show a more granular picture of the rain and snow distribution. The white and hatched areas signify snow, blues and greens are rain.

For comparison I’ve posted the GFS6z precipitation type chart for the same time below. Both of these charts suggest snow is more likely in central and northern parts of the UK.

At this stage the key points are:

1) There is much uncertainty
2) There is the potential for snow

Summary

Uncertainty is the name of the game. There is a risk of rain, sleet and snow in the coming days which could accumulate and become disruptive, but saying exactly where and when is very difficult. Some computer model runs are suggesting a quick transition to milder weather next week but in general a gradual warm up looks more likely. Even this isn’t definite and there is a chance of the cold digging in or returning.

Chart viewer

Cold and winter’s first snow for some?

The next few days will bring the coldest spell of the winter to date and even parts of southern England could see a few flakes of snow. The cold spell looks like lasting well into next week and as milder air tries to return from the west there is a chance of snow.

In the next 24 hours showery rain, sleet and snow will push eastwards. In the north and over the Welsh mountains significant accumulations of snow are possible tonight. Over much of lowland southern Britain rain is more likely but I wouldn’t rule out the chance of snow. The GFS6z precipitation type chart below shows rain turning to snow tomorrow morning in the south east and over high ground such as the Chilterns there could be a temporary covering.

The wintry mix clears eastwards tomorrow leaving brighter weather but further showers  will develop. These will be mostly in the west and they could fall as snow.

Cold weather continues this weekend. On balance it looks increasingly dry and frosty but this morning’s GFS6z run suggested the possibility of some snow in the south on Sunday. I’ll keep an eye on that but currently there isn’t much support from the GEFS and other computer models.

Wintry next week?

Next week is shaping up to be interesting. Milder Atlantic air probably tries to return and as this bumps into the cold block over the UK there is the potential for disruptive snow. Things are very uncertain and significant snowfall requires a number of variables to fall into place.  In general it looks increasingly likely that colder weather will hold on for much of next week, at least in central and eastern areas.

Summary

The next few days will be quite cold and there is the potential for some rain, sleet and snow. Cold conditions are likely to hang on well into next week and as milder air tries to return from the west the result could be snow.

Chart viewer

Cold prospects this week

Temperatures will be dipping during the next few days and it remains showery. There is the potential for snow in places, especially over higher ground, but parameters at lower levels look very marginal.

Tomorrow brings further showers, in the north they will fall as snow over higher ground and perhaps turn wintry at lower levels.  Snow is also probable over the Welsh mountains but elsewhere the showers mean rain.

On Wednesday and Thursday more organised bands of showers are likely to spread eastwards. On my Saturday Buzz update I flagged up the possibility of these bringing a risk of snow farther south. Recent computer model run still showing the possibility of a wintry mix but in the south I’d expect wet snow to be mostly restricted to high ground.  The GFS12z chart below is for 06:00GMT on Thursday 15th January and shows rain clearing from southern counties. There’s the possibility of a few flakes of snow but I don’t expect those of us in the south to be building snowmen!

During Friday and the weekend the cold conditions persist but it becomes mostly dry and sharp overnight frosts are probable. Some computer models show milder air returning from the west by Sunday but I think a more plausible scenario is for the cold to hang on through the weekend. During the first half of next week milder conditions probably return from the Atlantic. Some transitional snow is possible but in recent years rain preceded by snow events have been rare for most of the UK.

Chart viewer

Rain, sleet and snow on Thursday?

A colder period is expected to develop next week. The duration and intensity of it remain open to question and across the southern half of the UK temperatures look marginal for snow.

On Monday, Tuesday and Wednesday showers continue and in the north these will probably turn increasingly to snow. In the south rain remains likely. Thursday could be interesting because there are suggestions of a disturbance pushing southeastwards across the country. This brings the risk of a period of rain, sleet and snow, however, the details are very uncertain and it’s possible the computer models will drop this disturbance in subsequent updates.

This morning’s GFS0z shows the potential disturbance bringing a band of precipitation southeastwards on Thursday.  The precipitation type chart below for 06:00GMT on Thursday 14th January shows a mix of rain, sleet and snow clearing southeastwards with snow mostly on its back edge as colder air follows in. There is a lot of fluidity in the medium range computer model output at the moment so I’m not convinced this outcome will be correct.

Longer term prospects?

By Friday things become increasingly uncertain. Recent GFS runs have shown the colder pattern breaking down quickly with milder air returning from the south west. European model runs such as ECM are more inclined to build high pressure over the UK and keep colder  air over us until the start of the following week.  The outcome could well be a mix of both but it’s too early to be confident.

Chart viewer

Cold spell – HEADS UP 6

A colder period continues is expected next week. There is uncertainty about its longevity and during the last 24 hours computers models have suggested an increased chance of milder air returning relatively quickly.

During the first half of next week I’m expecting colder weather to gradually extend southwards. By mid week maximum temperatures across the southern half of the country will probably be in the 5C (41F) to 8C (46F) range and in the north it will be a few degree colder. There will be showers around and these probably increasingly fall as sleet or snow in the north with accumulations likely over higher ground. There could be a wintry flavour in heavier showers in the south too, though I doubt many of us down here will be building a snowman at this time.

What happens through the second half of the week is less clear. Some of the recent deterministic forecast model runs show mild and wet weather quickly returning from the southwest, albeit bringing the risk of heavy snow for a time over the northern mountains. This morning’s ECM0z run showed  a pulse of very mild sub tropical air crossing the southern half of the UK during the weekend 16th and 17th January. This morning’s GFS6z run also brings back mild conditions through the same weekend.

Is that it?

Taken at face value the recent operational GFS and ECM runs suggest there has been a big change in the outlook for next week with the chances of a lengthy cold spell being washed away. However, the operational runs only provide a snapshot of the most likely outcome based on what is thought to be the current state of the atmosphere. Given that it’s impossible to be entirely sure this is correct  (there simply isn’t enough data collection around the globe) the computer models are re-run a number of times with their initialisation conditions altered. Each adjusted run is a member of the ensemble model, on TWO that’s the GEFS which is run by NCEP in the USA. The UK Met Office have their own system (MOGREPS), as does European Centre for Medium-Range Weather Forecasts (ECMWF).

So does the GEFS still suggest there is a chance of a longer cold spell? Yes. The plot below for London is from this mornings GEFS 6z run, that means it is initialised with data from 06GMT, but the cycle doesn’t complete until about 12GMT which is why I often refer to it as the midday update. Most of the individual runs show quite a cold air mass between 13th and 17th January. Temperatures at the 850hPA level are close to -5C which could lend itself to showers (if there are any) turning wintry and perhaps even falling as snow at times.

Beyond the 17th January things become less clear cut with quite a lot of the individual runs quickly bringing back much milder air. However, there is still a sizeable cluster of runs which keep the colder conditions in place. During the last 24 hours or so the colder cluster has become smaller but it still contains about 40% of the total number of runs. This suggests things are finely balanced and I’d not be surprised if one or more of the 12z GFS, ECM and GEM operational runs shows a lenghtier cold spell again this afternoon.

Summary

The weather is set to turn colder during by the middle of next week. It won’t be especially cold but showers are likely to fall as snow in the north and they could turn wintry farther south. Towards the end of next week milder air could return from the southwest but this is uncertain and the ensembles still suggest a reasonable chance of a longer period of cold weather.

Chart viewer

Cold spell – HEADS UP 5

A colder period of weather is expected next week. There could be some snow around and the chance of it being more than a brief cold snap has increased significantly in the last 24 hours.

My last few updates have suggested the likelihood of the cold snap next week being quite short but today’s data suggests this may not be the case. In fact recent GFS/GEFS model runs are pointing towards the possibility of a genuine cold spell lasting for perhaps one week and increasing the prospects of snow falling more widely. There is still plenty of time for significant changes in the forecast evolution for next week so at this stage it remains a case of following developments closely.

On the London GEFS6z plot below most of the individ model runs are showing cold conditions for much of next week. I will throw a caveat in here and say a few are going for a mild or even very mild pattern, I think largely as a result of high pressure collapsing into the continent and a southwesterly flow developing across the UK. For a change this winter a quick transition back to a mild pattern isn’t the favoured outcome but it’s still too early to discount the possibility.

Snow prospects

Will it snow? If I had a £ for every time I’m asked this I would long since have retired. Snow in the UK is often a hit and miss affair away from high ground in the north. Also, nationwide snow events are surprisingly rare even during cold spells. The best I can do at this stage is say there are likely to be sleet and snow showers around, these will probably be focused on northern and coastal counties. Another thing to bear in mind is that snow in the UK is often the result of mild air trying to return from the Atlantic and the boundary between wet and white is often very narrow.

Summary

I’m pretty confident next week will bring the first cold spell of the winter and after the exceptionally mild December it will be quite a shock to the system. I remain uncertain about the duration and intensity of the cold but the latest data is favouring a longer and colder period of weather than looked likely 24 hours ago. I’ll post regular updates in the coming days.

Chart viewer