Penellype's Weather Channel

[Penellype]

This was the result of a rapidly developing storm that had a track rather further south than normal. There had been mention of the possibility of thunder from some of the weather guys, but seemingly concentrated on the channel rather than Cumbria. The snow was one of those very finely balanced situations where cold air comes in on the back of an exiting low as the wind moves round to the north. There can be a huge temperature drop as this happens.

I was watching racing from Leopardstown (Ireland) on Sunday afternoon, and it was raining there. I turned it off to go and cook tea at about 4ish and was surprised to see pictures on social media of the last race run in a snowstorm, with snow lying on the track.

After a rather better day in some places today, rain is already moving into the south west and this will move north and east over night, dumping quite a lot of rain as it goes. It will probably clear to showers by tomorrow morning, with another band of rain following from the west. Milder tomorrow, but cooler after, remaining mainly unsettled but with more chance of frosts at night. We may get a repeat performance of last weekend sometime around the weekend, but models have yet to make up their minds about the depth and track of any storm.

[Muddy_Boots]

Interesting - the version I know of that is "The north wind doth blow and we shall have snow". Interestingly neither of the books that I have on old weather lore mention this one (both written by people in the south of England) so it must be a northern saying.

I'm from Derbyshire and where I come from that was always the saying, it never ceases to amaze me how true it becomes most years even in this time of so called 'global warming' but we won't go down that topic of discussion.

[Penellype]

Regarding Sunday's snow, an interesting article about why it caught out the forecasters here: https://www.netweather.tv/weather-fo...y-a-case-study.

Of the 5 variables that "must be right" for snow to fall, only ONE was right on Sunday (and that was borderline). It was the intensity of the precipitation with resulting evaporative cooling that caused the rain to turn to snow. I think the forecasters can be forgiven this one - you often hear it said that if the dew point is above zero "it can't snow".

[1Bee]

To be honest, your thread here has made me forgive forecasters all 'mistakes' in perpetuity... an understanding of the complexity of the data I already had, but I hadn't realised how often the models used in the past are proving incapable of coping with our changing systems. It's a miracle they get anything 'right'.

[Penellype]

To be honest, your thread here has made me forgive forecasters all 'mistakes' in perpetuity... an understanding of the complexity of the data I already had, but I hadn't realised how often the models used in the past are proving incapable of coping with our changing systems. It's a miracle they get anything 'right'.

There are huge difficulties with forecasting a system as complex as the weather, because the whole planet is interlinked (and some things outside of the planet too, like the sun). Sometimes these things contradict each other - this winter has been an excellent example. Everything looked set up for a cold winter, particularly after Christmas - we are in solar minimum, which favours "northern blocking" (high pressure over the pole) and we are in a weak El Nino, which favours northern blocking. We had an early sudden stratospheric warming, which favours northern blocking, and indeed we had quite a bit of northern blocking. Northern blocking in winter often means that the UK is cold. The AO, which is a measure of the pressure difference between the north pole and the mid latitudes, was negative for most of this time. We "should" have had a cold winter. However, the QBO, which is related to winds and pressure differences along the equator, started off in its easterly phase and was becoming more westerly through the winter. This appeared to affect the NAO, which is similar to the AO but localized to the Atlantic, measuring the pressure difference between Greenland and the Azores. This remained stubbornly slightly positive, with lower pressure over Greenland pushing the higher pressure towards Canada and favouring milder weather for the UK (and very cold weather over the USA). This was virtually impossible to predict - because the NAO area forms part of the AO area, the indexes are normally broadly similar, with only short term differences. [Note that this is a very simplified explanation, so much so that it could be wrong as my understanding of these things is probably not great].

Add to the above the fact that a model is only as good as its program and input data, and that there are still many things we don't properly understand, everything is changing quite fast due to increasing global temperatures, and there are inevitable and unavoidable errors in measurements, and it is amazing that the models get things roughly right as often as they do. Errors get magnified the further away the forecast is, and that's why you should always treat anything further than 5 days away as a vague possibility rather than an accurate forecast. Its also why the media hype stories of weeks or months of snow/cold/heat etc are always pure guesswork, usually based on exaggerating the most extreme possibility from the long range and therefore unreliable forecasts.

[Gillykat]

Sounds grim

Not quite the word I used when I saw the rota!!! But, as things sadly turned out, I would have probably have had to work anyway as one of my workmates is off this week because her son-in-law dropped dead playing football on Sunday You never mind covering for things like that because it's not something 'planned' if you know what I mean Back at work tomorrow after two days off so I'm going to pull my boss about my holidays.....and his reluctance to give us payslips, amongst other things. Last year I loved my job but now.....love the part-time hours (more time for gardening and getting a dog) but just want to throttle the boss......he couldn't organise a p*** up in a brewery!

[Penellype]

Not quite the word I used when I saw the rota!!! But, as things sadly turned out, I would have probably have had to work anyway as one of my workmates is off this week because her son-in-law dropped dead playing football on Sunday You never mind covering for things like that because it's not something 'planned' if you know what I mean Back at work tomorrow after two days off so I'm going to pull my boss about my holidays.....and his reluctance to give us payslips, amongst other things. Last year I loved my job but now.....love the part-time hours (more time for gardening and getting a dog) but just want to throttle the boss......he couldn't organise a p*** up in a brewery!

Oh dear - its things like that which put everything else in perspective . I hope you sort out some holiday.

[Penellype]

Several deep low pressure systems around over the next few days which will give some very windy weather. The exact track of these is uncertain but the strongest winds will be to the south and west of the lows.

Before this a shallower low will move across the south of the UK tonight, pulling in a northerly wind behind it. As the jet stream is currently to the south of us, cold air will move in to the north and west of the low and this will produce a borderline snow situation. Do not be surprised if you see sleet, snow or hail to low levels in the northern half of the country over the next couple of days.

Keep an eye on warnings for wind during the next week, especially around Tuesday/Wednesday. The track and timing of a low around this time is uncertain, but some models are winding it up into something potentially quite nasty. It is beyond the reliable timeframe at present, but has consistently been showing up as a potential named storm. There will be plenty more rain too.

Models are undecided when this unsettled spell will end, with the GFS currently wanting to build high pressure towards the end of the week, while the ECMWF remains very unsettled and cool.

[Chippy Minton]

Helen Willetts on the telly box started the forecast with "I'm getting worried about what I'm seeing developing..." or some such. Not what one wants to hear from the forecasters!

Tying everything down and checking the Ark.

New pond should be full though

[Penellype]

Helen Willetts on the telly box started the forecast with "I'm getting worried about what I'm seeing developing..." or some such. Not what one wants to hear from the forecasters!

Tying everything down and checking the Ark.

New pond should be full though

I suspect she is concerned about the very deep low that is forecast to form to the north west of Scotland on Tuesday. Normally these lows move away north east, but because the jet stream is south of us at present, it is likely to move more in a south east direction, pulling strong winds across the country. This wants keeping an eye on, but its depth and track are far from certain yet, with quite big differences between the models.

[Gillykat]

There's a weather warning in effect for Northumberland for snow from 2am - 11am tomorrow Very windy today too.....it's howling around outside as I type!

[Penellype]

Yes, multiple warnings have now been issued for wind, snow and ice, both for tomorrow and mid-week. https://www.metoffice.gov.uk/weather...ce/uk-warnings

[Gillykat]

So far ~ 10.08am ~ it's just a light drizzle ad barely a breath of wind

[Chippy Minton]

Snow on the cars when I woke up, all gone now, sleety horrid rainy stuff falling, greyhound in full reverse on looking out of the door.

[Penellype]

Yet more yellow warnings for wind, rain and snow for various parts of the UK today and tomorrow. The storm (as yet unnamed) that is coming in tomorrow looks like dumping large amounts of rain in the west and some snow in the north, along with yet more high winds.

Fortunately this appears to be the last of the string of storms for now, and high pressure is expected to build next week, bringing drier and much less windy weather.