A Winter's Tale

Looking at the records for Glasgow airport going back to 1973 it’s very clear ice days are more easily achieved in the first half of winter. Number of days with maxima -0.5C or lower: November 7 December 52 1-15 Jan 15 16-31 Jan 6 Feb 2 Obviously the figures for the first half of winter are distorted by the cold spells in 1979, 1981, 1982, 1987, 1995, 2000, 2009 and 2010 and there has been a lack of notable cold spells occurring after mid January in the last 50 years. The number of days with maxima below -0.5C is almost the same for November as the second half of winter and there have been more days with maxima below -6C in the first half of winter than -0.5C in the second. I think this emphasises how difficult it becomes to achieve low maxima as winter progresses. The days which recorded such maxima mid January onwards are: 18 Jan 1975 (-1), 17 Jan 1977 (-1), 31 Jan 1977 (-1), 15 Feb 1979 (-1), 20 Jan 1984 (-2), 30 Jan 2006 (-1), 20 Jan 2011 (-1), 28 Feb 2018 (-3). It just goes to show how extreme the beast from the east was to achieve such as low temperature so late in the season and accompanied with heavy snow and strong winds. It will be interesting to see if 2024 can join the list of the rare number of days post 15th January with maxima no higher than -1C.

A very cold evening after a fine sunny winter’s day. Glasgow airport already down to -5C after a high of 2C. Last night’s snow shower left a dusting which has remained and is certainly more than I would expect from a northerly. As for tomorrow I’m not expecting much more than an inch at best though I suspect some places where precipitation is heaviest and with some height there could be 5-10cm. It’s very much a nowcasting situation. While tomorrow doesn’t appear likely to be a memorable snow fest hopefully most of us will have a decent covering that lasts for a few days. After tomorrow it seems we could be in for some low temperatures (particularly at night). I’m sceptical of ice days in central Scotland as they are rarer in the second half of winter. However low night time minima is possible (especially if there is snow cover and light winds). The Met office are hinting at sub -10C for Glasgow which would be pretty notable should it happen. So while this cold spell is not the classic we hoped for it’s better than having no cold spell. Much of northern Scotland have experienced frequent snow showers with drifting lying snow and hopefully tomorrow this of us in central Scotland will join in on the action.

Fluffy snowflakes falling now instead of graupel.

A shower has arrived which appears to be light graupel. Encouraging to see showers making it this far south already.

At the moment it looks like this cold spell will be closer to Dec 2022 and Feb 2021 than 2009/10. The models are showing a week long cold spell which is a decent length but obviously not as impressive as the two week+ spells in 2010. Since then there haven’t been too many cold spells longer than a week. Here’s a list of spells with 7+ consecutive days of 5c or lower maxima at Glasgow airport: Jan 2011 (7), Jan-Feb 2012 (9), Nov-Dec 2012 (9), Jan 2013 (14), Mar 2013 (8), Jan 2015 (7), Jan-Feb 2015 (7), Jan 2016 (9), Jan 2018 (7), Feb-Mar 2018 (9), Dec 2020-Jan 2021 (13), Jan-Feb 2021 (10), Feb 2021 (8), Dec 2022 (10). There is the chance the cold spell could be extended as there is uncertainty concerning the strength of the high pressure over Greenland, the possibility of a wedge of high pressure persisting to our north as well as cold weather being difficult to shift. The duration of cold temperatures is only one factor in determining the magnitude of a cold spell. The depth of cold is another. According to the GFS 06z we could be looking at 4-5 days with widespread maxima of 0C or lower which is pretty notable. In the past 50 years at Glasgow airport there have only been two days with maxima -2C or lower in the second half of winter (there’s a chance we could see such a temperature during this spell). There’s also the chance of notable minima - especially in the highlands and parts of the southern uplands - as the charts posted on this thread showed last night. I think we lows of -15 to -20C are quite likely in the highlands (-20C a possibility) and in central Scotland we could see -7 to -12C. With regards to snow it’s too early to tell but I’d say most places north of Dundee should be in the firing line of most showers. In such set ups, for most inland places we are relying on features popping up out of nowhere to deliver a surprise. It’s possible this cold spell could be predominately dry like Dec 2022 but even the spell provided a decent fall here towards the end. Also there’s always the chance of a battleground snowfall during the breakdown. Looking at the models there is a feature which could bring snow (should the warm sector play ball) to western and central areas although I suspect it may end up tracking further south to impact SW Scotland and NW England. So, while this cold spell may not (yet) be a repeat of 2010 as some charts promised over a week ago this still looks like a reasonable cold spell and at the moment the signs are positive for the rest of winter. This winter has already produced a couple of decent falls so I’d take one big fall of 10cm+ or a smaller fall which leaves a few cm lasting for a few days. Despite the complaints from some in the model thread about the lack of snow (primarily for southern England) Scotland is in a decent position to experience snow and hopefully we’ll enjoy widespread snow cover. The charts at the moment remind me a little of late Dec 2000 which lasted for little more than a week. At Glasgow airport there were 5 consecutive ice days, a low of -11C and one fall of snow dumped around 20cm in the area. It’s an example of how cold spells don’t need to be prolonged to pack a punch. And you don’t need stonking high latitude blocking to produce impactful winter weather. Looking through the archives of some of the notable periods of winter weather it’s striking how quite a lot of the charts are not that impressive at face value (at least by the standards set by some in the model thread).

Apparently the latest run from the ECM is a disaster according to some on the model thread. Well, it appears they may be on to something as it looks a disaster for travelling across Scotland. Still lots of uncertainty regarding specifics but there are lots of reasons to be optimistic for Scotland experiencing a cold and potentially snowy weather in the heart of winter. Potentially, this month could end up with a sub zero mean temperature for Scotland should the cold persist into the last third of the month.

Top 30 In Scotland: Dec 2010 -1.7 Jan 2010 0.2 Dec 1995 0.3 Feb 2010 0.4 Dec 2009 0.5 Jan 2021 0.6 Feb 1994 1.3 Jan 2001 1.3 Mar 2013 1.3 Feb 1996 1.4 Dec 2022 1.6 Feb 2018 1.6 Dec 1996 1.7 Dec 1999 1.9 Feb 2001 1.9 Jan 1995 2.0 Jan 1997 2.0 Jan 2011 2.1 Jan 2018 2.1 Feb 2013 2.2 Feb 2016 2.2 Dec 2008 2.3 Dec 2012 2.3 Mar 2018 2.3 Jan 1994 2.4 Mar 2001 2.4 Dec 2001 2.4 Mar 2006 2.4 Jan 2019 2.4 Jan 2009 2.5 Jan 2015 2.5 Feb 2021 2.5 Interestingly, despite the notable periods of weather which occurred during this months, Dec 2000, Feb 2009 and Jan 2013 fail to make the list and Feb 2021 will miss out should this month record a mean of 2.4 or less.

Well the 2nd day of December produced a surprise snowfall and the 2nd last day of December delivered one of the most surprising snow events I can recall. In recent years frontal snow-rain events have struggled to result in anything more than a brief covering. The lack of a warning by the Met office suggested more of the same but ultimately up to 7cm of snow fell which is the most for a frontal event here since 2013. The downside of most frontal snowfalls is how rare it is for snow cover to last and today is no different. However the excitement of seeing the snow pelting it down and readily accumulating makes it worth it - even more so when it’s unexpected - and a proper frontal snowfall was well overdue. Despite how mild December 2023 has been it’s remarkable I’ve seen more 2 inch + snowfalls than in December 2010 - in fact I can’t recall this happening before in December. The winter of 2021/22 was similar in terms of over delivering decent falls of snow in an otherwise poor winter. Hopefully 2024 can offer more sustained periods of winter weather. The models so far today appear to be more optimistic about the prospects of cold and possibly snowy weather commencing the second week of January. I’m expecting January to be much colder than December though it wouldn’t surprise if it doesn’t surpass this month’s snowfalls. Having already experienced a couple of decent falls I’m looking forward to more sustained snow cover or at least some fine, crisp winter conditions instead of the Atlantic driven weather of late. At the moment it looks like we could have a lot to look forward to as we enter the new year.

Is that Helensburgh? That’s impressive so near to the coast.

Quite a memorable event with 6.5-7cm - this could have been an amber warning let alone yellow. The Met office are lucky today is a Saturday during the holidays.

The second surprise snowfall of the month with 4.5cm so far - easily best frontal snowfall event since 2018.

Some pictures from this morning’s snow.

Around 5-5.5cm which is pretty impressive considering the Met office expected 1-3cm above 200m.

A nice surprise snowfall to start winter. Around 3.5-4cm of snow after yesterday’s maximum of -1C. Winter 2023/24 has delivered more in just over 24hrs than some entire winters. Hopefully a sign of things to come.

After a cold few days we are set for even colder weather to end November and December. The early winter period isn’t renowned for cold and settled conditions (it has been particularly rare in the years since 2010) so it’s refreshing for winter to start on a seasonal note for the second year in a row. Currently the cold spell appears to be a lesser version of last December with a shorter duration and it’s unlikely we’ll get back to back days of maxima widely well below freezing and minima below -10C. In terms of snow last December’s cold spell was dry with most of the snow confined to northern Scotland - although I enjoyed a decent fall towards the end of the spell. This year looks largely the same with largely dry conditions and snow showers predominantly affecting northern and eastern parts of Scotland. As always with cold spells there’s the chance of surprises coming out of nowhere. Here in the Glasgow area I’ll be happy to see the first snow flakes of the season though I have my fingers crossed for at least a covering. The model thread has been very up and down over the last few days (what’s new) over details of the length of the cold weather and snow prospects. It does seem unlikely that the cold weather will not persist beyond Dec 5th though past experience suggests we should not underestimate the ability for cold spells to last longer than initially expected - especially with a lot of cold air across Europe. The fact we are experiencing this cold spell in spite of unfavourable factors boded well for later in the winter so even if things turn less cold by mid December I expect it won’t be long before we see a return of seasonal weather.

-3.5C at Kinbrace is a new UK minimum temperature date record for 13th September.

A couple of other stations set new records for September maxima. 26.8 Leuchars 25.3 Inverbervie An impressive number of weather stations have set new records. 29.3 Kinloss (7 Sep) 28.8 Glasgow Bishopton (8 Sep) 28.7 Lossiemouth (7 Sep) 28.5 Aviemore (8 Sep) 28.3 Aboyne (8 Sep) 28.2 Drumalbin (8 Sep) 27.8 Altnaharra (8 Sep) 27.8 Strathallan (8 Sep) 27.3 Loch Glascarnoch (7 Sep) 27.2 Edinburgh Gorgarbank (8 Sep) 27.1 Tain Ridge (8 Sep) 27.0 Dyce (3 Sep) 26.8 Leuchars (9 Sep) 26.6 Aultbea (7 Sep) 26.1 West Freugh (5 Sep) 25.5 Machrihanish (8 Sep) 25.3 Inverbervie (9 Sep) 25.2 Wick (8 Sep) 24.5 Cairnwell (8 Sep) 24.4 Islay (7 Sep) 24.3 South Uist (8 Sep) 24.1 Kirkwall (8 Sep) 22.1 Baltasound (8 Sep) 21.3 Bealach na Ba (8 Sep) 20.7 Lerwick (8 Sep) 20.2 Cairngorm (8 Sep) 20.0 Fair Isle (8 Sep) 19.3 Aonach Mor (8 Sep) I think Kinlochewe, Achnagart, Fyvie Castle and Tyndrum set new records aswell. Some stations were not far off all time record maxima: Kirkwall (24.8), Loch Glascarnoch (28.0).

Quite a remarkable period of weather across the British Isles. Southern parts of England have had a record number of consecutive 30C+ days for September. Areas further north have also experienced exceptional warmth for the time of year. Yesterday saw Northern Ireland set a provisional record maximum temperature for September with 28.0 at Castlederg. Other stations in Northern Ireland set new records for September: 27.3 Magilligan (7 Sep) 27.1 Aldergrove (8 Sep) 27.0 Ballypatrick (8 Sep) 26.6 Thomastown (7 Sep) 25.6 Glenanne (8 Sep) 25.5 Lough Fea (8 Sep) 25.5 Portglenone (8 Sep) In Scotland the highest September temperature since 1906 was recorded and quite a lot of stations set new record highs for September: 29.3 Kinloss (7 Sep) 28.8 Glasgow Bishopton (8 Sep) 28.7 Lossiemouth (7 Sep) 28.5 Aviemore (8 Sep) 28.3 Aboyne (8 Sep) 28.2 Drumalbin (8 Sep) 27.8 Altnaharra (8 Sep) 27.8 Strathallan (8 Sep) 27.3 Loch Glascarnoch (7 Sep) 27.2 Edinburgh Gorgarbank (8 Sep) 27.1 Tain Ridge (8 Sep) 27.0 Dyce (3 Sep) 26.6 Aultbea (7 Sep) 26.1 West Freugh (5 Sep) 25.5 Machrihanish (8 Sep) 25.2 Wick (8 Sep) 24.5 Cairnwell (8 Sep) 24.4 Islay (7 Sep) 24.3 South Uist (8 Sep) 24.1 Kirkwall (8 Sep) 22.1 Baltasound (8 Sep) 21.3 Bealach na Ba (8 Sep) 20.7 Lerwick (8 Sep) 20.2 Cairngorm (8 Sep) 20.0 Fair Isle (8 Sep) 19.3 Aonach Mor (8 Sep) This period of weather would easily have made a decent mid summer heatwave. Had this heatwave occurred a month or two earlier I would imagine southern England would see temperatures in the mid 30s (with a few spots in the high 30s) and low 30s for parts of northern England and Scotland.

New station records for September maxima today: 28.8 Glasgow Bishopton (equals date record at Charterhall in 2021) 28.5 Aviemore 28.3 Aboyne 28.2 Drumalbin 27.8 Altnaharra 27.8 Strathallan 27.2 Edinburgh Gorgarbank 27.1 Tain Ridge 25.5 Machrihanish 25.2 Wick 24.5 Cairnwell 24.3 South Uist 24.1 Kirkwall 22.1 Baltasound 21.3 Bealach na Ba 20.7 Lerwick 20.2 Cairngorm 20.0 Fair Isle 19.3 Aonach Mor A truly exceptional period of weather.

Joint warmest day of the year at Glasgow airport with 28C - equalling warmest September temperature on the same day in 2021. After the very disappointing weather following the record breaking June this has been a very welcome last hurrah for summer. The past week would make for a decent warm spell in the middle of summer let alone September and it just shows what’s possible this late in the year.

New record September maxima at a number of weather stations: 29.3 Kinloss 7 Sep 28.7 Lossiemouth 7 Sep 28.4 Aviemore 7 Sep 27.4 Altnaharra 7 Sep 27.3 Loch Glascarnoch 7 Sep 27.0 Dyce 3 Sep 26.6 Aultbea 7 Sep 26.1 West Freugh 5 Sep 25.0 Machrihanish 7 Sep 24.4 Islay 7 Sep 24.3 Wick 4 Sep 23.4 South Uist 7 Sep 20.7 Bealach na Ba 7 Sep 20.3 Cairnwell 7 Sep 18.7 Aonach Mor 7 Sep 18.2 Fair Isle 7 Sep