Autumn Forecast issued 29/08/2014

Issued 29/08/2014 on my Facebook page - posted here for posterity and easy access...

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Autumn Forecast

I will start with the usual caveat that seasonal forecasts can and do go wrong. Predicting 5 days ahead is difficult enough – giving an exact forecast for a particular weekend in November right now is impossible. However I can give a guide as to what I am expecting.

My summer forecast was issued on June 3rd and is available for review if you scroll down quite a way - and I have posted on my old blog for easy access - http://jameswinfieldweather.blogspot.co.uk/2014/08/summer-forecast-2014.html.

My headline was for an above average summer in terms of temperatures, but also rainfall. Sunshine at least slightly above average. And the best chance of significant thunderstorms in our area for some years.

Amongst the things that I feel I got right were no month-long heatwave for July but good spells of hot weather - sunshine and temperature predictions for June and July, thunderstorm potential. August was furthest from being accurate, in particular by predicting average rainfall when we received well-above average though at least I stated that the month would be more unsettled in the second half which it has been. And I did have low confidence in my August forecast.

I am happy with the overall accuracy and will look to build in what I have learnt for next summer.

The headline for this autumn is for a dry September and October, often with above-average temperatures. A gradual breakdown to unsettled conditions in November with above average rainfall and an early taste of winter to finish.

September will begin with high pressure over the UK, or drifting to the east. This will bring lots of warm or possibly hot sunshine. There is the potential for it to briefly drift west bringing a cooler flow and perhaps some showers around 7th - 10th September. I then expect high pressure to move back over the UK to bring further warm sunshine for the rest of the month. Depending on the exact position of the high pressure, there could be some chilly nights in the second half of the month. Rainfall to be very low, perhaps as few as 3-4 days with rain falling, mostly from weak weather fronts toppling over areas of high pressure occasionally.

Overall I expect well-above average sunshine amounts, above-average temperatures and below-average rainfall.

I am 90% confident of this outcome.

October has a strong signal for high pressure to be to our east and this has been something that I have been confident about for several months now, which will mean southerly winds and well above-average temperatures at times, especially in the first half of the month.

The second half of the month is most likely to see the Atlantic high come into effect, bringing cooler north-westerly or northerly winds and occasional showers or weak weather fronts, but mostly dry.

Overall I expect above-average sunshine amounts, slightly-above or above average temperatures and below-average rainfall.

I am 70% confident of this outcome - less confident about the second half.

November will see the return of low pressure systems, though I expect the Jetstream to be tracking slightly north of here, say over Scotland so although rainfall will likely be regular, I expect that we will miss the heaviest of the rain. High pressure will likely nudge into the south at times so there will be a couple of 3-4 day drier spells.

I do feel that there is a chance of a brief cold spell towards the end of the month.

Overall I expect slightly below-average sunshine amounts, slightly above-average temperatures and above-average rainfall.

I am 80% confident of this outcome.

Early signs for winter are for a generally mild winter, and a wetter than average winter although there are no signals for it to be as extreme as last winter – in fact high pressure should nudge up from the south-west at times.

However, there are conflicting signals that it could be a very cold and very snow-filled winter, at least for January onwards. Certainly there is a much higher chance of snow this winter than last winter – which is something I stated before last winter. Added on volcanic uncertainty in Iceland and potential effects in the unlikely, but possible, event of a really major eruption and this winter is definitely one to watch.

Thankfully my winter forecast is still 3 months away!

If you have made it this far then it would be appreciated if you could share the forecast and/or invite friends. A lot of love and effort goes into this forecast and they are normally a reasonable indicator of the upcoming season.

Enjoy autumn

— in Reading.

Summer Forecast 2014

Posted here after summer to create an easily viewable link.

Original on Facebook, post date 3rd June 2014.

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Welcome to my Summer 2014 Forecast

I begin, as always with a caveat that long-term forecasting is horrendously difficult and can only really be produced in terms of the most-likely expected patterns.

My long-term followers will know I got my summer 2013 forecast pretty spot on – predicting a month-long heatwave in July when most other forecasters were expecting another washout. However this winter I underestimated the amount of rainfall (slightly above average was my prediction), my spring and autumn forecasts were reasonable though a long way from perfect.

The headline is for an above average summer in terms of temperatures, but also rainfall. Sunshine at least slightly above average. And the best chance of significant thunderstorms in our area for some years.

This is what I believe is the most likely outcome – it doesn’t mean a washout or a long heatwave won’t happen.

So onto my monthly breakdown.

June is most likely to see a strong area of high pressure develop to our north-east over Scandinavia, particularly in the second half of the month, when I also expect the Jetstream to be running south, bringing very wet conditions to France, for example. Both will be major factors in our weather here in Berkshire.

The first half of the month will be characterised by low pressure to our south-west, often bringing heavy showers for several days at a time. However the wind direction will be favourable for temperatures and should bring at least one very short spell of very warm/hot weather in the first half of the month – but only for 1-2 days before thundery rain arrives once more.

Assuming high pressure builds over Scandinavia as expected during the second half of the month, this should reverse the script to several warm, settled days, though morning cloud often taking a while to clear, interspersed with shorter spells of heavy showers – potentially some cracking thunderstorms, and then the pattern repeating itself.

The first half of the month will have around 10 days of rain falling, the second half around 6.

Overall I expect above-average rainfall, above-average temperatures and around average sunshine, perhaps slightly below average.

80% confident on this outcome.

July is most likely to see high pressure taking more of an influence over our weather, with both high pressure to our east, and also the Azores high nudging in from the south-west.

However, unlikely last year I do not expect any long heatwaves.

The first week of July (give or take) I believe will be sunny and hot. This then being followed by a thundery outbreak from the south which again could potentially bring some very high rainfall totals.

Once this system clears out of the way I expect fresher conditions with ridges of high pressure building from the south-west (the Azores high) – but this not being especially strong, so a few fine and fairly warm days will be interspersed with showery days, this pattern continuing for much of the month.

Overall I expect slightly above-average rainfall (though below average if we miss the early-mid month thunderstorms), slightly above average temperatures and slightly above average sunshine amounts.

65% confident on this outcome.

August has no clear signals, which is particularly unhelpful.

My suspicion is that we will see drier, sunnier weather in the first half, perhaps just touching the hot category for a while.

The second half being slightly more unsettled in terms of afternoon showers/thunderstorms developing but still some decent sunshine around.

Overall I expect above average temperatures, above average sunshine and average rainfall.

50% confident on this outcome.

So not bad at all, especially when you compare it to the summers of 2007 to 2012.

That said, things do change, and I will regularly update you on my long-term thoughts as summer goes on.

It would definitely be appreciated if you would like/share and invite friends.

Looking further ahead, and the early signs are for an unsettled September, a significant warm spell in October and back to cool and unsettled in November though turning settled but frosty towards the end.

But please take these autumn thoughts with a bigger pinch of salt than the council has left over from the winter.

Dare I mention winter?!

Last winter I said that the winter of 2014/15 would see more snow than the winter of 2013/14. Which will take one snowflake to be accurate.

My hunch is that we will see an early onset of cold weather in late November/December, but then turning milder and more unsettled as winter goes on.

Enjoy the summer.

Sunday 3rd February 2013

Tonight will be cloudy, dry and mild, 9'C.

Monday will also be fairly cloudy but some sunny spells, 8'C, 4'C overnight.

Tuesday will be cold and windy, with some showers, and these could fall as snow. Any snowfall is likely to be transient and melt quickly. 4'C by day, 2'C by night. I have a feeling that I may have to update this forecast nearer the time.

Wednesday will feel colder in the northerly wind, albeit possibly not be as cold at 5'C, wintry showers are possible but sunshine is the main story. A frost overnight as the wind dies down, down to -1'C.

Thursday and Friday, the coldish air will still be in place, it should be fairly sunny, around 4'C with a frost overnight, down to -2'C or perhaps even lower.

The weekend looks interesting with a battle between cold air to the east trying to build, and milder Atlantic weather wanting to bring rain back in - and as we saw many times in January this battleground brings lots of snow potential - and of course lots of forecasting headaches.

Currently I do not feel the synoptics are right for a prolonger cold spell and that any snow this coming weekend will be quickly replaced by another spell of milder and wetter weather - it depends on how well entrenched the cold gets this week, I would say there is a 30% chance of this coming cold spell lasting.

Sunday 27th January 2013

Missing the snow?

Tonight, early showers clearing, mostly dry and chilly, 1'C. However there is a chance of a small feature bringing a downpour around midnight or just after.

Monday sees a band of cloud and rain spread from the west, rain around 2pm to 9pm, give or take, quite showery in nature, 8'C. Noticeably windy. 7'C overnight.

Tuesday through to Wednesday morning will be wet, with further long spells of rain, possibly 30 hours on continuous rain. Missing the snow yet? Wednesday afternoon should see brighter weather but with showers.

A very mild wind on Tuesday could see us reach 13 or even 14'C. Wednesday less mild at 10'C. Mild at night too.

Thursday morning sees the next area of rain, followed by sunshine and showers, fresher at 8'C.

Friday is interesting, an area of heavy rain close to the south, with a cold blast coming from the north - it could turn to snow overnight. One worth watching but only 25% likely.

Any cold snap next weekend I expect to be short-lived.

There is certainly the potential for further cold weather the week after though most likely down here not to be cold enough for snow, say 5 to 7'C with rain.

I am expecting a further significant cold spell during February, starting around 10th February on current tracks.

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I don't always remember to post my forecasts to my blog as I mainly use Facebook - for those with Facebook you can check my weather page.

Wednesday 16th January 2013

Time to put some details on Friday's snow forecast.

Before we start - today was what is known as an 'Ice Day' as the maximum temperature was -0.8'C.  Well this is assuming that the temperature doesn't go above 0 between now and midnight which is a pretty safe assumption.

Actually it is worth mentioning a very small risk of a very light snowfall during Thursday, but it should just remain dry.

There is less uncertainty in the snow for Friday, thankfully, than the previous events.

The uncertainty is around how far east the band of snow will travel and where the heaviest will be.

At the moment it looks to start around 7am, and will be generally moderate, sometimes heavy and will last well into Saturday.

Saturday it will be lighter and patchy before dying out.

By the time Saturday morning comes, around 10cm should have fallen.  Before you ask about your area - pretty much the whole of England is included in this forecast, away from the coasts.

I can only say 60% confidence in this specific outcome.  There is a 15% chance of a much heavier snowfall, say 30cm by the end of the weekend, if the band of snow gets stuck over us.  There is also a 15% chance of a much smaller snowfall, say a few cm.  And still a 10% chance of a total disappointment.

Either Sunday or Monday there is another spell but this is much more uncertain as to whether it will be rain, sleet or snow - your guess would be as good as mine right now.

Needless to say it will remain cold - around 0'C by day, and at night between -2'C and possibly as low as -10'C after the snowfall - how cold it gets overnight depends on how clear the sky becomes.

Chance of something milder by Wednesday next week with a thaw thanks to a more normal jetstream pattern - but far from guaranteed.  Any thaw has a good chance of being temporary.

Monday 14th January 2013

The last few days have been a reminder at just how marginal it is for snowfall in this area, and how difficult it is to forecast.  It has been somewhat head-ache inducing, I do actually feel a bit sorry for the professionals.

I feel I was a bit harsh on the Met Office on my post on Saturday.

Just about the end of the snow, for now at least, but getting much colder.

This evening and tonight will see further wintry showers, falling as snow towards midnight and some places will see another light covering.  Icy, down to -2'C.

Tuesday will be rather sunny but it is unlikely to get above freezing all day and down to -5'C overnight with a hard frost.  Just a small chance of a snow shower.

Wednesday also looks fairly sunny, 0'C at best during the day, -5'C at night with the potential of perhaps -8'C.

Thursday again fairly sunny, a small chance of some light snow, 0'C by day and -4'C overnight.

Friday and Saturday have the potential for more spells of snow.

It may turn briefly milder by Sunday.

Thursday 10th January 2013

Model watching is never easy. I have bad news...and good news!

Saturday's snow event is massively downgraded. Rain will set in during the morning and it will still very likely turn to snow somewhere between 3 and 6pm. However the amount of precipitation is much reduced, and I would say 3cm is the most likely amount of snow. That said, the M4 is the boundary between rain and snow so it might not even snow that much. There is still a 20% of NO snow. 3'C at most during the day, down to -5'C overnight and icy.

Sunday will see the cold easterly wind dig in and snow showers could get as far inland as Reading - potentially a cm or two, but it there is a better chance it stay dry. No chance of rain - it would be snow. 0'C by day, -6'C overnight.

Monday will start sunny but very cold, a band of cloud will approach from the west with snow for the evening and overnight. You would be advised a close eye on this one as it could cause chaos if it arrives in rush hour. 3-5cm quite possible even in low-lying Reading. -1'C during the day, -3'C by night.

Tuesday and Wednesday remain cold or very cold with further snow showers possible. 0'C by day (or less), -3'C at the most by night...much colder if clear skies.

Then there is a lot of uncertainty for Thursday onwards, but there are realistic chances of possibly the most memorable winter event of my lifetime. Some of the model projections are showing huge amounts of snow for the south.

If what is currently projected comes off in its entirety there would be a huge amount of chaos for several days.

However - I cannot emphasise enough how often models change and how often snowfall events get downgraded during cold snaps (though they also appear out of nowhere!!)

It is more likely to stay cold with the potential for further snow for some time. 7-10 days though 7 weeks would not be impossible.

Tuesday 8th January 2013

Rule number one in weather forecasting - if models are showing easterly winds, always take them with a pinch of salt. If models are predicting a westerly wind 10 days out then it will almost definitely happen - if they are showing an easterly wind just 3 days out, remain sceptical.

However, my long-range winter forecast expected a cold second half of January and this is the back-up for it.

I'm not yet 100% certain of snowmageddon but it could be a very memorable spell of weather.

Read on...

Wednesday I am hopeful of some spells of sunshine but with a band of cloud close to the south it is only 60% likely. 8'C by day, 2'C by night.
Thursday looks wet all day, but even this close it is not certain, around 7'C.
Friday looks cool and mostly dry, perhaps some light rain in the morning, 5'C by day, 2'C by night.
Saturday is very interesting. Low pressure heading from the west with cold air digging in from the east. Currently money would be on rain turning to snow (40%) with 5-10cm possible but it could just rain (25%), it could just snow 10cm or so (25%) - and it might just be dry and cold (10%). Around 1'C by day and -4'C overnight.

Remember - forecasting snow in Reading is marginal and it is quite possible I will not be able to say with certainty even the day before.

Sunday looks very cold, but currently looks dry with the chance of more snow overnight. -2'C by day, -8'C at night.

So be prepared for significant disruption. But remember it isn't definite yet. I'd say I am 80% confident of a cold spell, 60% confident of some snow, 40% confident of disruptive snow.

For Sophie's Mum

(Written 31/12/2012).

Well, that is the last of the rain for a while (as I first suggested two weeks ago that it would be).

There is a small chance of a passing shower tonight, but it should be dry for most, down to 3'C in fresher air by the early hours.

And then high pressure builds from the south-west. If only it would do this in July. Never mind.

2013 will start with sunshine, 7'C for Tuesday, more cloud at nig...ht so only down to 2'C.

Wednesday will see a weak weather front cross during the day, so it will be cloudy, there may be bits of light rain but nothing much and it will introduce milder air - 7'C by day, 9'C by night.

Thursday to Saturday look mostly cloudy affairs, the sun might come out and if it does it could feel surprisingly pleasant, there could also be some light drizzle at times but most likely dry, around 10 to 12'C.

And the week after also looks mostly dry, perhaps a weak weather front Monday/Tuesday passing through, but nothing much.

At the moment the area of high pressure looks set to be situated such that it will give mostly cloudy but mild weather - it wouldn't take too much of a change in positioning to bring more of a clear but colder continental airflow.

In fact, as January progresses I expect, as I have said previously, that colder air is likely to head over the UK and the potential for snow should increase in the second half of January.

Very difficult to give details of if or when it will snow 3 days away let alone 3-4 weeks away but the potential is definitely there. As it is for February.

Happy New Year to all - please spread the word if you appreciate my forecasts.

https://www.facebook.com/#!/readingweather?fref=ts

A June Of Three Thirds?

I expect June to be split into three.  The first part wet, but not always as cold as this, the second part to be fine and dry but not massively warm, and then a heatwave, most likely with downpours, to finish.  The unsettled part will be for around another 10-16 days, the two spells afterwards for between 4-8 days each, still very uncertain.

I will talk about July and August later.

I have to admit that the Jubilee weekend forecast was the worst I have made for a while.  It was a very difficult one to predict - hence why nobody was saying anything about what the weather would be until a few days in advance - I am trying to do it much further in advance and I have to hold my hands up and say I got that one wrong.  Sorry.

It was only on Thursday 31st that I was able to get a true grip on what was going to happen, such was the unpredictability of it.  Why was it so unpredictable?  A combination of things from a very southerly jet-stream wanting to move north towards the UK, the first tropical storm of the season, Beryl which was unusually early to get mixed up in the Atlantic, a hot plume from Africa and high pressure building to our north-west, all made it a total mess and very unpredictable.

I took a punt and lost.

I am more certain about this week being unsettled though and I give you details:

Wednesday may see some sunshine but don't be fooled, showers will develop , some heavy, possibly torrential downpours, at any time.  You may get lucky and miss them all in which case it will be a pleasant day at around 17'C, but expect heavy downpours.

Thursday will see a deep area of low pressure, you will notice it being rather windy, and an area of heavy rain will spread across during the day, we are talking 5-6 hours of heavy rain.  It will clear through in the evening to lead to showers overnight.  Between 14'C and 16'C.

Friday will be showery with the potential for longer outbreaks of heavy rain too, around 14'C, cooler though if it is cloudy and wet all day.

At the moment, Saturday could turn out fine at 18'C but heavy rain is on the way, most likely for the evening and overnight, and a real soaking quite likely.  Again, this far out it is not possible to say whether the timing is spot on, there is a risk of the rain arriving during the day.

Sunday will see more rain, and turning cooler.

At the moment I think it most likely that there will be more rain the week after before finally drying out for a while but that is not certain.

I would suggest at the moment, around 18th is my guess for when it might start to turn settled, but cool to start.

Around 25th is my guess for the heatwave.

But things can change and probably will so keep an eye out on my Facebook page for regular short updates.

July I expect to be quite hot at times, some good sunny spells, but also some thundery rain at times, a good mixture but some good sunshine for sure.

August I expect to be drier, hot to start but cooling down towards the end.

If you like my forecasts, please spread the word.  Ta.

James Winfield's Weather Forecast 3rd May

April was wet.  Very wet. Triple the average in some areas.

I would happily bet that May will be wetter than April.

There is also plentiful cold air coming down from the north, as you may have felt - Thursday in Reading did not get above 9.5'C.

But it isn't all doom and gloom because there is a large pulse of hot air in the upper atmosphere which is coming from the south.

Don't get too excited though, because you should know cold air and warm air don't get along easily from your physics education (no I don't remember much sadly).

A cold week will lead into a very wet week, but how it ends depends upon...magic...or perhaps what happens during the week coming, so I cannot be sure yet but I favour the solution of next weekend being very warm and thundery at 60%.  The other solution is a calm, pleasant, sunny, weekend but cold for the time of year with possible frost overnight and around 13'C - one of those is your reward for the week of rain.

This weekend might end up relatively dry.  Cloudy, damp, bits of rain, nothing to shout about.

Next week is concerning as it could possibly rain heavily on Monday, Tuesday, Wednesday and Thursday without much in the way of relent.  If you are living in an area which is likely to flood, be prepared.

So next weekend, as I said 60% it will be 24'C but thundery, 40% of glorious sunshine and 14'C.

I will keep updates on the Facebook page as I do not have the time to put into regular forecasts at the moment.

Oh, I am still expecting a good summer.  Hot July.  Hot August.  I see no reason why not.

Updated Weather Forecast - Thursday 19th April 2012

You know what?

I kind of miss doing my weather forecasts.

I might just have been having a lover's tiff with forecasting, I do not know.  I think I need to forget about not having much of an audience - how many people read my forecasts shouldn't be my judgement of whether it is worth doing them - it has to be more about me and what I enjoy.

And I do enjoy forecasting, and (normally, I think) getting it right.  So I'm going to do it anyway.

This unsettled spell is going to last.  I do not see this pattern changing much during April and May, except for brief glimpses.

Friday I see as slightly less showery.
Saturday I see back to lots of heavy showers around.
Sunday could be quite fair, still some showers, but lighter showers, and lighter clouds.
Monday - a big ass load of rain to make up for being slightly drier on Sunday.  Big rain.

Followed by more days of heavy showers.

Temperatures will remain cool for the time of year, around 11'C, cooler in the rain, but a touch more on the drier days like Sunday, say 13'C.

So far this year's weather is kind of reminding me of 2003, to an extent, and certainly latter parts of last year did.  Remember 2003?

I think my forecasts are becoming like the rain - intermittent.