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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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.

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