Scotland

31 Oct 2024 – Wave cloud downwind of NE Scotland

A terrific display of orographic lee wave cloud across NENE North East Scotland that extends eastward into Norway. Unusually, all the LCBR across northeast Scotland are reporting zilch in terms of medium or upper cloud heights this lunchtime, so I had to revert to some Weather Watcher images as a last resort.

These Weather Watcher pictures show the base of the lenticular ACAC Altocumulus clouds are generally associated with settled weather and will normally appear white or grey with shading. Height of base: 7,000 - 18,000 ft Shape: Bands or areas of individual cells Latin: altum - height; cumulus - heap Altocumulus clouds are small mid-level layers or patches of clouds, called cloudlets, which most commonly exist in the shape of rounded clumps. There are many varieties of altocumulus, however, meaning they can appear in a range of shapes. Altocumulus are made up of a mix of ice and water, giving them a slightly more ethereal appearance than the big and fluffy lower level cumulus./CICI Cloud, comprised of ice crystals that form wispy filamentous tufted streaks or ‘mare's tails’ at high altitude usually 16,500 to 45,000 ft./CSCS Ice cloud forming a thin, more or less uniform semi-translucent layer at high altitude, usually 16,500 to 45,000 ft. cloud is very high, maybe 18,000 ft or higher by the look of it.

Scotland, Wave Cloud

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2024 – Extended Summer Index [MJJAS]

Not a great deal of difference from the results of the Summer index for 2024 really, with East Anglia still having the highest index and Northern Scotland the lowest. The result for the extended summer in Northern Scotland were much improved though, from a summer index of -27 to and extended summer index of -7, thanks to a spell of good weather and record temperatures in May, and another settled warm spell in mid September.

Scotland, Summer, Summer Index

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State of the UK Climate 2023

I notice that the report State of the UK Climate 2023 that has just issued by the UKMO says that ‘Climate change may be causing dramatic changes’, but eight to twelve days with temperatures >=28°C across Ross-shire in 2023 is NOT one of them. I recorded one such day here in 2023 in StrathpefferStrathpeffer Strathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469., Easter Ross. I realise that the statistics are from a number of stations across the whole county, but there’s absolutely no way that there were as many as eight of them in 2023, even if you include results from Kinlochewe in Wester Ross. Back to the printers!

Climate, Royal Met Society, Scotland, UKMO

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May 2024 – Weather Summary

May 2024 was a record warm month in Scotland. In the north of Scotland mean temperature were +3.5°C above the 1991-2020 LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO., and beat the previous record set in 1889 by 1.6°C. The UKMOUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy say the high mean temperatures were down to high overnight minimum temperatures, that may be true for the whole of the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland., but not for northern Scotland where the mean maximum anomaly of +3.3°C was very similar to the mean minimum anomaly of+3.5°C.
May was also another rather dry month in NW Scotland with rainfall totals just 63% of the LTA. Although there were some very sunny days total sunshine for the month was just 85% of the LTA.

May, Scotland, Weather Summary

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Scotland’s shires

Highland & Eilean Siar weather forecast area

I monitor the weather forecast for the Highland and Eilean Siar region of the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland., so a map like this that delineates the exact area comes in handy when trying to decipher the forecast from the Met OfficeUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy. Basically it comprises the whole of the Highland region plus the Western Isles. Even after being up here on and off for over 15 years, I still have a job trying to visualise the precise areas they are trying to describe. One thing I do know though is that just using terms such as ‘in the east’ or ‘in the west’ doesn’t help in an area as large and oddly shaped as this one is. Neither is using towns and cities such as Inverness and Nairn as reference points. Do you have any idea where Lochaber is? Or for that matter where Sutherland and Caithness are, and how far Ross-shire (or should that be Ross and Cromarty) extends? Shires in Scotland are a very complex subject, as this Wikipedia article explains.

How the shires of Scotland once looked.
How the regions of Scotland look now.
Scotland

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Jan-May 2024: Disparity in precipitation across Scotland

Just a couple of hyetographs so far this year to compare precipitation totals at Loch Glascarnoch in Wester Ross with those at Gogarbank Edinburgh further south. The difference is very marked, with only 87.7% of the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO. in the north and 169% of the LTA in the south during the first five months of 2024. That large Edinburgh total is probably due in part to a couple of thundery days that occurred in April and May. Having said that, I’m sure that the tracks of the numerous lows and their frontal systems has much more to do with it.

Precipitation, Scotland

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The mystery photo of Ben Wyvis

I was researching Ben Wyvis in Wikipedia for an article that I was writing and came across this incredible picture looking east from Loch Glascarnoch towards Ben Wyvis, with what looks like a shallow layer of fog covering both the loch, the A835 to its south, and the glen beyond. I would guess the picture was possibly taken on high ground to the south of the loch, and judging by the direction of the shadows on the fog layer at around lunchtime.

The credits show that the picture was taken by D.J.MacPherson with a creation date of 2009-01-02. At first I thought that there had been some kind of trickery involved with its production, but when I checked the weather chart for midday on the second of January 2009 and found it had been a frosty, clear anticyclonic day in the northwest Highlands with fog reported at Aviemore and Kinloss which seemed to fit. The only odd thing is that there’s no proper snow cover on Ben Wyvis.

What clinched it was when I checked the NASANASA The National Aeronautics and Space Administration is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. EOSDISEOSDIS The Earth Observing System Data and Information System is a key core capability in NASA’s Earth Science Data Systems Program. Designed and maintained by Raytheon Intelligence & Space, it is a comprehensive data and information system designed to perform a wide variety of functions in support of a heterogeneous national and international user community. Worldview visible satellite image for that day.

So my bit of amateur “meteorological sleuthing” paid off 😉

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Fog, Satellite, Scotland

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Sunday, 28 January 2024 | Warmest January day in UK

28 January 2024
Max Temperatures [06-18]

Sunday the 28th of January 2024 was an interesting day across the Northwest of Scotland. The manual maximum temperature reading of 19.9°C at Achfary in Sutherland caught the UKMOUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy out completely, it was only yesterday that they were predicting the highest temperature today would be 16°C in the north of Wales, with a high of only 14°C forecast for the north of Scotland. It seems they have some serious problems forecasting temperatures in foehnFoehn A foehn, is a type of dry, relatively warm, downslope wind that occurs in the lee (downwind side) of a mountain range. It is a rain shadow wind that results from the subsequent adiabatic warming of air that has dropped most of its moisture on windward slopes (see orographic lift). As a consequence of the different adiabatic lapse rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes. conditions like these in their mesoscale model. Provisionally, the 19.9°C at Achfary exceeded the old record of 18.3°C by a whopping 1.6°C.

Interestingly, Achfary now holds two maximum UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. monthly records, one for December and now one for January
Tweets from the UKMO on the 28th & 29th January 2024
Thermograph for Loch Glascarnoch
A diurnal range of 19.8°C from a max of 17.4°C to a min of -2.4°C.
Comparison of the maximum anomalies on Sunday [06-18] with the minimum ones on Sunday night [18-06]

There was also a strange area of moderate/heavy rain which developed across central Scotland on the radar during the early afternoon, well ahead of the cold front that was just coming into the Western Isles at 1455 UTCUTC Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT).. In StrathpefferStrathpeffer Strathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469. it produced large spots of rain from 1330 UTC, and a spell of moderate rain just before 15 UTC. The rain seemed to be falling out of blue sky at times, and even at 15 UTC there was only seven oktas of thin CICSCICS A combination of Cirrus Cirrostratus cloud and some thin lenticular ACAC Altocumulus clouds are generally associated with settled weather and will normally appear white or grey with shading. Height of base: 7,000 - 18,000 ft Shape: Bands or areas of individual cells Latin: altum - height; cumulus - heap Altocumulus clouds are small mid-level layers or patches of clouds, called cloudlets, which most commonly exist in the shape of rounded clumps. There are many varieties of altocumulus, however, meaning they can appear in a range of shapes. Altocumulus are made up of a mix of ice and water, giving them a slightly more ethereal appearance than the big and fluffy lower level cumulus. in the sky. The wind in the tops of the trees must have been close to force six from 270° so all I can assume it was being blown a very long way. The only thing I can think that caused it was an upper cold front running ahead and parallel to the cold front.


Saharan dust producing this peachy coloured high level CICS
Courtesy of @HighlandWeather
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January, Scotland, Temperature, Warm

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The discriminatory impact based warning system

The above is an amber warning issued for Brighton and Hove, East Sussex, Kent and West Sussex for Monday the 22nd of January 2024. It’s a perfect example of how winds in Scotland have to gust in excess of 80 mph before an amber warning is issued there, but only 70 mph in England. Below is the Met OfficeUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy’s own UKV model for 06 UTCUTC Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT). on Monday morning, the spot values clearly show gusts of 69 kts across NENE North East Scotland and 61 kts across the coast of Sussex.


The impacts on a roof or chimney stack are identical, the last time I checked, the laws of physics are exactly the same in Brighton as they are in Kirkwall, and a 70 mph gust that removes slates off a roof in either place will have the same consequences if it falls on someone’s head. But impact based warnings are weighted in favour of population density, and hence the reason why the 69 kt gust is viewed as less ‘impactful’ in the NE Scotland than the 61 kt gust in Brighton. Completely balmy. Impact based warnings are discriminatory, and not for the right reasons. Bring back threshold based warnings.

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NSWWS, Scotland, Warnings

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The Bermuda Triangle of Scotland

Although we’ve seen a number of snow showers this morning in StrathpefferStrathpeffer Strathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469., they all proved light and were on their last legs before they managed to put a dusting down along the Strath. This is our sixth winter here, and I reckon that snow showers in a winter situation like this with a 30-40 knot N’NW gradient generally have a range of around 90 km as they come in land from the north coast before they simply just run out of steam, or should that be water vapor. Obviously with a stronger gradient, deeper cold air and increased instability, or change in wind direction that 90 km longevity might well increase.

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Scotland, Snow, Strathpeffer

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Spectacular inversion

Snow covered Munros sticking out of the inversion

Inversions are quite common in anticyclonic conditions, and there’s been one in the last week across the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. where an intense anticyclone (1046 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar) has been meandering across northern Scotland for much of that time. Yesterday (11 January 2024) the inversion lowered to ~3,000 feet across Scotland to allow the Munro’s to peek above it. This morning the dew pointDew point The dew point is the temperature to which air must be cooled to become saturated with water vapor, assuming constant air pressure and water content. on Aonach Mor (1130 M and just to the south of Ben Nevis) dropped to -34°C and the humidity to ~5% which is extremely low and doesn’t happen that often.

Further east in the Cairngorms a similar thing happened on CairngormCairn Gorm Cairn Gorm (Scottish Gaelic: An Càrn Gorm) is a mountain in the Scottish Highlands. It is part of the Cairngorms range and wider Grampian Mountains. With a summit elevation of 1,245 m (4,085 ft) above sea level, Cairn Gorm is classed as a Munro and is the seventh-highest mountain in the British Isles. itself. The thermographs below are for Cairngorm itself (1245 M) and the AWSAWS Automatic Weather Station on the edge of Aviemore (220 M) in the Strathspey. Despite the low stratus at Aviemore temperatures still fell close to -4°C, whilst on the tops it was a relatively balmy 4°C.

Above and below the inversion, from the Ptarmigan Restaurant and Loch Morlich.

Many years ago as an observer at RAF Kinloss I remember contacting Rob McElwee at the the BBCBBC The British Broadcasting Corporation (BBC) is the national broadcaster of the United Kingdom, based at Broadcasting House in London. It is the world's oldest national broadcaster, and the largest broadcaster in the world by number of employees, employing over 22,000 staff in total, of whom approximately 19,000 are in public-sector broadcasting. (I can’t for the life of me remember how I did this, I must have phoned) to alert him to the fact that we had spent that day walking on Cairngorm and the northern corries in warm sunshine above the inversion. He managed to show a visible satellite image of the UK in his evening forecast (9.25 pm?) that showed the only bit of high ground peeking above a sea of low cloud covering the UK was the northern Cairngorms, good old Rob McElwee!

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Inversion, Scotland

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Heavy rain across Scotland | 6-8 October 2023

A very wet weekend across Scotland with many reports of flooding on both the road and rail network. It never picked up much news coverage nationally or in Scotland itself. That’s not surprising because most local news is done by posting stories, and particular images and videos, on social media these days. The idea of having reporters on the ground to chase up and write about stories like this have almost gone.
What amazes me that is we would rather close the railways down for the weekend rather than fix the problem. What remains of our railway network is a vital infrastructure and should not be prone to flooding like this. I don’t believe that in the 21st century that we can’t invest and install adequate drainage to prevent the ever increasing number of events like this from happening.

There was upwards of 200 mm on the high ground in the wettest places as you can see in these estimates from weather radar. I think we ended up with ~87 mm in around 48 hours here in StrathpefferStrathpeffer Strathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469.. Although the ground was temporarily saturated and did flood for a while, it wasn’t long before the ground absorbed it, because up until now this year has been much drier than average.
It all came in stark contrast to the sunny skies and very warm weather further south across England, Wales and Ireland, with temperatures of 26°C or higher, whilst in Scotland, sub-zero temperatures and snow was reported on the highest of the Cairngorms.
Finally this event, even though it didn’t have any strong winds associated with it, should have been declared a named storm. Why it wasn’t defies any logic, especially when two amber warnings were issued for it. Most of the public will have already forgotten about storm Agnes, but memories of this heavy rain and flooding might stick around a bit longer.

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Flooding, Rain, Scotland

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Misleading weather radar

Not a day to be putting too much trust in what the weather radar is telling you. Most, if not all of the precipitation across the northwest of Scotland is obviously falling from medium level altostratus and not reaching the ground. We really do need better radar coverage across the north of Scotland which will certainly help with radar over shooting and picking up medium level rainfall across the northwest Highlands.

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Scotland, UKMO, Weather Radar

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May extremes in Scotland

Courtesy of anomaly charts for the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. from the UKMOUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy, here are the warmest and coldest May’s since 1910 across Scotland. Not a huge variation in temperature, ranging from the warmest in 2018 of 2.32°C above to 2.18°C below the 1961-1990 LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO. in 1923. The yellow box at the bottom right-hand corner is the predominant Lamb Weather type for the month. The wettest May in Scotland since 1910 was in 2011 when over 223% of the average rain for the month fell. The driest May was in 1984 when just over 27% of the average fell.

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Climate, May, Rain, Scotland, Sunshine

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A distinctly nippy IONA

Sunday, 11 December 2022 – 12 UTCUTC Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT). temperature anomalies

Dear Diary
Another very cold day across all parts of IONAIONA Islands Of North Atlantic. Yes I know there's an island called Iona, but this is so I don't have to use the term 'British Isles' when referring to the whole of Ireland and the UK. this Sunday, exceptionally so across parts of the south with anomalies as low as -10°C this lunchtime, as this cold spell continues. Many areas will see an ice day today with temperatures remaining sub-zero this afternoon. Finally, the northern Highlands of Scotland, have lost that persistent and tenacious east northeast wind of the last week that has been funneling a feed of milder winds into the Moray Firth. No doubt it’s just taking a breather and will be back later in the week.

Anomalies, Cold, Frost, Scotland

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Cold front makes slow progress

Dear Diary
The cold front is making painfully slow progress across Caithness and Sutherland this afternoon and evening whilst continuing to plunge southward further east down the meridian. Negative dew pointsDew point The dew point is the temperature to which air must be cooled to become saturated with water vapor, assuming constant air pressure and water content. refuse to advect southwestward and any showers become scattered this evening. A frustrating day. What is going on diary?

Analysis, Scotland

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Is Aviemore on top of a hill?

Dear Diary,
CFCF Chris Fawkes is a BBC Weather Forecaster, presenting across all the BBC’s channels. believes for some reason that the weather station in Aviemore is up at about “three or four hundred metres”. The station height at Aviemore in reality is just 220 metres AMSLAMSL The height Above Mean Sea Level., not on top of a hill, but in the Spey valley and within a kilometre of the river itself. That’s what makes it such a great frost hollow in the shelter and shadow of rising ground the other side of the A9 to its west. In fact only one of the four sites he calls “higher communities” are that high, Merthyr Tydfil is at ~180 M, Buxton ~305 M and Enniskillen ~51 M.
CF, thinking that Aviemore is some kind of hill station will have no doubt coloured is thinking of observations from their over the years, but then again he does suffer from Scotia MyopiaScotia Myopia The inability to recognise the weather in Scotland in any of their forecasts, often preferring to talk about anywhere else in the UK, but usually the SE of England. Often incurable. quite severely.

Courtesy of Ordnance Survey

BBC, Scotland, Stations

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Visible satellite image

Dear Diary,
Quite a good visible satellite image of Scotland for the archives. That low cloud looks like it’s slowly edging northeastward and would explain those contradictory temperature charts this lunchtime from the BBCBBC The British Broadcasting Corporation (BBC) is the national broadcaster of the United Kingdom, based at Broadcasting House in London. It is the world's oldest national broadcaster, and the largest broadcaster in the world by number of employees, employing over 22,000 staff in total, of whom approximately 19,000 are in public-sector broadcasting. for 06 UTCUTC Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT). tomorrow. Look at the length of the shadow that upper cloud is casting across the Grampians or am I imagining things, and that small vortex to the east of the Orkneys.

Courtesy EOSDISEOSDIS The Earth Observing System Data and Information System is a key core capability in NASA’s Earth Science Data Systems Program. Designed and maintained by Raytheon Intelligence & Space, it is a comprehensive data and information system designed to perform a wide variety of functions in support of a heterogeneous national and international user community. Worldview
Satellite, Scotland

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