Penellype's Weather Channel

[Chippy Minton]

Talk at the weekend turned to the grit stockpile. We used it all up last winter, or actually spring really. Some years we use half a bag, others we've been through 4. So what is it to be this year?

[Penellype]

Talk at the weekend turned to the grit stockpile. We used it all up last winter, or actually spring really. Some years we use half a bag, others we've been through 4. So what is it to be this year?

This year is very very difficult. ALL of the long range models (including the CFS) were forecasting a cold winter at the weekend, cold in December and getting colder as winter progresses seems to be the main theme. BUT the latest CFS charts for the 3 winter months are all showing high pressure to the south and low to the north, which is a mild, wet and windy pattern, eg for January:



Long range models are experimental and can't be relied on, changing their minds very frequently, as the CFS proves above.

This is this morning's GFS ensemble chart for the rest of November and the first 10 days or so of December:



That's forecasting milder, wet and windy for the next week at least, after which there is a lot of uncertainty, but the one thing that does not look to be to me is cold!

So really, I haven't a clue. Sorry.

[Nicos]

Talk at the weekend turned to the grit stockpile. We used it all up last winter, or actually spring really. Some years we use half a bag, others we've been through 4. So what is it to be this year?

Get in 4 bags Chippy....then at least we'll know for sure we'll have a mild winter!

[Penellype]

The changeable weather continues this week with more low pressure systems coming in from the atlantic. A brief ridge of high pressure building today will result in a drier slot and a couple of colder nights and chilly days tomorrow and Wednesday before milder air and more rain arrives later in the week. Wind, rain and then cooler temperatures are likely at the weekend after which the models don't seem to have much of a clue. Yesterday lunchtime it looked like they were settling to a drier, colder spell, today its back to huge uncertainties (anywhere within a 20C upper air temperature range possible, from +10 to -10). Most of the runs seem to be drier* next week, implying higher pressure, and it will be the exact positioning of this that is causing the uncertainties.

*drier at this time of year can easily mean cloud, fog or persistent drizzle, not necessarily sunshine.

[Chippy Minton]

Ah, normal service has resumed (at least for the NW of England), wind, rain, colder, repeat......

Really wet this morning, "lawn" looks like the Somme again. Greyhound is in the bad books due to the beige carpet now having a paw print motif.

[bramble]

I know it won't last, but we had a beautiful dry, sunny day here today.
What a difference the weather makes.

[Gillykat]

Same here - beautiful cloudless blue skies and sunshine yesterday and today with this morning being VERY frosty and -2.3 at 8am.

Tomorrow, my day off, is forecast rain

[Penellype]

Yes, the rain has arrived a little earlier than was forecast at the weekend. There is a yellow warning for rain for south Wales, and one for ice in the north east due to rain falling on frozen ground. In general I am finding the forecasts very unreliable even in the short term at the moment - it rained all Monday morning when it was forecast to be dry, and Monday night was forecast to have a minimum of 1 whereas it actually went down to -3. Yesterday reached a maximum of around 2 here due to fog.

The reason for this is uncertainty in the exact track of the low pressures - the one on Monday was a little further north than expected and the northern edge of the rain therefore covered York. This can make a huge difference in the weather at affected locations.

Things are warming up again for the next couple of days with plenty of rain and some strong winds likely Friday-Saturday (there is already a yellow wind warning for the northern half of the UK but the area covered may change). This could well become storm Dierdre or Erik - confusion seems to abound as to which is next. After that it looks increasingly likely that it will get really quite cold at the start of next week, with night frosts and daytime temperatures in low single figures. Snow showers are possible in places. This is due to high pressure building to the west which will turn the wind into the north.

The models cannot agree on what happens next and several completely different solutions are on the table, many of them (but not all) cold. Be prepared for the possibility of an extended cold spell lasting a week or more. This is by no means certain, but quite possible. How it ends as well as when is also open to considerable doubt - one possibility is that the high pressure is gradually eroded by lows from the atlantic, resulting in snow for a time before milder air arrives from the west. However, if the high gets itself stuck to the north, pushing the jet stream south, we could be in for an extended spell of cold, with the driest conditions in the north, cold rain in the south and sleet or snow in between. The current GFS model goes for cold with wintery showers all week and then a strong atlantic storm barging its way in to produce snow, wind and then rain next weekend.

The message really is that forecasts are likely to be unreliable, newspaper headlines are likely to be predicting an ice age, and what the weather will be like in 10 days time is anyone's guess.

Weather warnings https://www.metoffice.gov.uk/public/weather/warnings.

[Penellype]

Next week's cold spell appears to be mostly off the table for now. The high pressure is still forecast to form over Scandinavia, but it is further east than previously predicted, meaning that after a brief drier and colder slot the wetter and milder weather is likely to return, possibly becoming stormy again by next weekend.

The reason for the chopping and changing in the forecasts is that very small and subtle changes in the position of the high over Scandinavia make a huge difference in wind direction and the source of the air over us. It would not take much of a change to bring the cold spell back into the forecasts.

The Met Office have decided that today's storm is not strong enough to name.

[Penellype]

Vast uncertainties in the forecasts as early as Wednesday as low pressure in the atlantic comes up against a block of high pressure over Scandinavia and the models don't know what to do with it. Some of them have the high holding fort and introducing colder air from the east, with the low either being deflected north or sliding south (possibly bringing sleet or snow on its northern edge) while others have the low smashing through the high. The danger is that the fronts associated with the low become stuck over the top of us, leading to heavy and prolonged rain and possibly flooding.

It looks likely that a stronger low will arrive at the weekend, although its track is uncertain, giving more rain and possibly severe gales. After that it is literally anyone's guess, so on the table for Christmas (just in range of the GFS model now) we have everything from mild, wet and windy to cold, showery and possibly snowy in places, to cold and frosty, to mild and dry (or foggy/cloudy)...

If anyone says they know what the weather is going to do at Christmas, take it with a huge pinch of salt for now.

This is the latest ensemble chart for York:



This morning that bump in a couple of days time reached 5 degrees, now it only reaches zero - a huge change for just 2 days away.

[Chippy Minton]

Yep, that's definitely Christmas in the north west... mild, wet and windy, cold, showery (possibly snowy), frosty, mild, dry, foggy and a bit cloudy...

What'll happen in the afternoon is anyone's guess (usually windy after the sprouts...)

[Penellype]

The low pressure that was forecast to bring a wetter end to the week has basically lost the battle with the Scandinavian high, and bounced off it back into the atlantic. The associated rain only got as far as the far west of the country, and instead of milder air moving in, the wind has moved round to the south east, dragging in cold air off the continent. The next couple of days will be cold with night frosts and daytime temperatures in low single figures especially in the east.

On Saturday the next low pressure moves in, and this is a bigger and stronger one. The warm front associated with it will move into cold air and there is a distinct possibility of snow as it arrives from the west. This is a knife-edge scenario, with snow likely over hills and in the north, but the models disagree about how much snow and whether or not it will fall as snow to lower levels before it turns to rain. Therefore don't be surprised to see snow almost anywhere from Wales and the midlands northwards (and possibly sleet further south than this) on Saturday, but equally don't be surprised if forecast snow falls as rain. Either way, away from Scotland and high ground in the north any snow is likely to melt by or during Sunday as the snow turns to rain.

For an up-to-date assessment of the likelihood of snow at the weekend, https://www.gavsweathervids.com/ is intending to do a "snow watch" video some time today, analysing the latest model runs and possibilities.

It will also become windy over the weekend as the low moves through.

[Gillykat]

I've just seen the forecast for Saturday up here in Alnwick and there's a weather warning in place for snow! We shall see.....

[bikermike]

We've had an odd one for a couple of days this week. Frost in the evening, melted by morning (7am)

[1Bee]

I clocked the weather warning and immediately logged in to the vine to check this thread...