Courtesy UKMOUKMOThe 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 StrategyMean Temperature Anomaly I make January just slightly colder than average across the whole of the UKUKThe 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..Extreme maximum and minimum A month of sharp contrasts in extreme temperature.Number of Air Frosts and Ice Days A fairly even distribution of air frosts across the country.Close to average generally, but much wetter across the north of England and drier further west and far north. I’m skeptical of no returns in snow so take many of these values with a pinch of salt.
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 UKMOUKMOThe 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 foehnFoehnA 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 UKUKThe 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 JanuaryTweets from the UKMO on the 28th & 29th January 2024Thermograph 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 UTCUTCCoordinated 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 StrathpefferStrathpefferStrathpeffer (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 CICSCICSA combination of Cirrus Cirrostratus cloud and some thin lenticular ACACAltocumulus 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
The waters around IONAIONAIslands 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. are all still well above average for early January. In fact the southern North Sea is +1.7°C above the LTALTALong Term Average. This is usually defined as a 30 year period by the WMO., and has been for some considerable time. It’s no wonder when we do get a cold Arctic northerly or a continental easterly, why temperatures are even more attenuated by the SSTSSTSea Surface Temperatures than they usually are.
A thirty year linear trend reveals that the UKUKThe 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. has become steadily warmer, wetter and sunnier in the last 30 years. The latest 12 month average at the end of December shows that the UK is currently running close to average for sunshine at 102%, but 111% for precipitation, whilst temperatures for the last 12 months are +0.81°C above the 1991-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO..
The curious thing is in a record warm world why has it been so cold in the last month in our bit of it? Answers on a postcard to the editor if you please.
A perfect example this month of how gridded climate data, even when interpolated onto a 1 km x 1 km fine grid, can make some places drier and warmer that they really where.
Wettest Octobers 1836-2023 Rather Surprisingly, only E Scotland had a record wet month in the gridded regional data.Oct 2023 Rainfall POAPOAPercentage Of Average I’m not convinced with the contouring. I’ve never looked at it in detail before It’s neither caught the 228% in StrathpefferStrathpefferStrathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469. (dark blue) or the 219% at Tain, and seems to have completely missed the 408% at WattishamThe interpolation & smoothing used by the Met OfficeUKMOThe 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 in producing its 1 x 1 km gridded data seems to have remove the wettest spots such as Wattisham completelyOctober 2023 Mean temperature anomalies Strange, several stations with anomalies of -0.5°C or lower across the Scotland not registering as a blue contour fill including Baltasound“though areas further north were generally closer to average”. Not quite accurate statement for some places across NENENorth East Scotland, and that includes Baltasound in Shetland, mean anomalies were 1°C below the LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.
Another very warm month across the Arctic. Warm in S Europe & NENENorth East America, but rather cold across Central N America and Scandinavia. North-south temperature gradient very evident across the UKUKThe 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..
Just a quick note to make a note about how late an Autumn it’s been in 2023. Its now past mid October, and many trees here in StrathpefferStrathpefferStrathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469. are still have more green leaves than they do brown, and although the Service and Birch tree have lost most of their leaves, others have not. I witnessed late, even very late Autumns in Devon over the years, but not here in Scotland since we returned five years ago. Why is Autumn late? Simple enough, summer was pushed into September and early October by a rather cold mid-summer as these anomaly charts show. The numbers in the pink boxes by the way are the mean anomalies for the gridded temperatures for the whole map, the graph is for temperatures at the grid point 57.5N 5W, the closest to home. It does make you wonder if meteorological summer should now be a four month period rather than a three which also includes September, whilst Autumn should now include December. By the way the title of that graph should read Mean Temperatures and not anomalies and another thing to put right.
One country in Europe that’s bucked the trend of a warm summer in 2023 was Iceland. I’ve noticed this in the monthly anomaly charts for mean temperature that I produce, so I decided to spruce up my chart grid viewer to see if I was right in my assumption, and as you can see in this chart of weekly mean anomalies I was. What caused it is may have been persistent high pressure across the Greenland ice cap to the northwest of Iceland, and a shift southward of the Icelandic low, which in turn allowed more days of northerly or north-westerly flows and hence the lower than average temperatures.
It’s not easy to verify these findings because even the Icelandic Met OfficeUKMOThe 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 site offers no real clues to how they categorised this summer’s temperatures. If you’re by any chance reading this in Iceland, please let me know how you found it😉
I was watching the Deep Dive video produced by the UKMOUKMOThe 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, and presented so well by Alex Deakin about the weather in September 2023 on Youtube as you do. He showed two anomaly charts for MSLPMSLPMean sea level pressure is the pressure at sea level, or, when measured at a given elevation on land, the station pressure reduced to sea level assuming an isothermal layer at the station temperature., one for the first half of September and the other for the second half that showed how anomaly charts for the whole month can sometimes be misleading. In this case it was how the remarkable warm spell in the first half of the month contrasted with the more mobile second half. The resulting anomaly chart for the whole of the September cancelled out the anticyclonic SE’ly in the first half that brought all the high temperatures.
The mean temperature for the UKUKThe 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. for September 2023 in the gridded series was 15.2°C which equalled that of 2006.
I have added a new viewer to my SYNOPSYNOPSYNOP (surface synoptic observations) is a numerical code (called FM-12 by WMO) used for reporting weather observations made by manned and automated weather stations. SYNOP reports are typically mad hourly and consist of groups of numbers (and slashes where data is not available) describing general weather information, such as the temperature, barometric pressure and visibility at a weather station. climate application to display estimated daily temperatures for the whole of the UKUKThe 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.. I use as many daily reported maximum and minimum temperatures from WMOWMOThe World Meteorological Organisation is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics. stations 03001 to 03950 as I can to calculate a UK mean for all stations below 250 M amslAMSLThe height Above Mean Sea Level.. That equates to around 120 observations each day. Nowhere near as accurate as the 1 km x 1 km gridded estimates from the UKMOUKMOThe 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, but good enough for me. As you can see it picks out the two heatwaves that have occurred this year. It does look like my estimates maybe just two high though, because mean temperatures in both July and August were much close to average than this. That’s not really that surprising because its totally dependent on an even spread of site location, but they tend to be further south and coastal sites. I suppose that I could use all available sites, even those on mountains, and adjust their temperatures down to sea level.
To say that the estimated global temperature for July made it the warmest on record of any month since 1850, it seems that no one bothered to let August know, and August had no intention of following suit, at least in our corner of the world.
Iceland was noticeably colder than average again.
The record high SSTSSTSea Surface Temperatures kept the North Atlantic ~ 1°C above the LTALTALong Term Average. This is usually defined as a 30 year period by the WMO..
The intense heatwave in southern France seems to have been cancelled out by an equally cold start to August that no one seemed to notice.
According to the 42 day forecast for 2M temperatures from the ECMWFECMWFThe European Centre for Medium-Range Weather Forecasts is an independent intergovernmental organisation supported by most of the nations of Europe. It is based at three sites: Shinfield Park, Reading, United Kingdom; Bologna, Italy; and Bonn, Germany. It operates one of the largest supercomputer complexes in Europe and the world's largest archive of numerical weather prediction data., it looks likely to be a mild, if not warm start to meteorological autumn 2023 across much of Europe. Let’s hope they’re forecast is wrong, it has been before.
What surprised me about temperatures in July 2023 was how the media went on a frenzy and adopted what was a North African heatwave and described it as an whole encompassing European affair, when mean temperatures across a large part of the continent for much of the month were below average.🤔
As you can see the colour scale I use for temperature is dynamic rather than using a fixed set of colours as preferred by the BBCBBCThe 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. and UKMOUKMOThe 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. It may not be transferable and directly comparable to any other month, but I find it much easier to find the hot and cold spots, and I can easily switch back to a fixed scale in software if necessary.
As far as I can see in the SYNOPSYNOPSYNOP (surface synoptic observations) is a numerical code (called FM-12 by WMO) used for reporting weather observations made by manned and automated weather stations. SYNOP reports are typically mad hourly and consist of groups of numbers (and slashes where data is not available) describing general weather information, such as the temperature, barometric pressure and visibility at a weather station. observations that I’ve downloaded for July 2023, and in complete contrast to July 2022 when temperatures exceeded 40°C, there wasn’t one single day when the maximum temperature [06-18] exceeded or equalled 30°C. Not many people know that😉
Courtesy Copernicus- the picture that caused all the fuss
Just a quick look back at the heatwave of July 2023 across the Mediterranean. There was a great deal of interest in this taken by the media in the UKUKThe 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., particularly the BBCBBCThe 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.. As far as I can see it was in my opinion, and that’s what this blog is all about, was sparked off initially by some overzealous reporting by the new (to me) Rome correspondent who was interviewing a selection of British tourists in the centre of Rome in the middle of a hot sunny day. I think this was in reaction to a warning from METEOAMMeteoAMThe Italian Meteorological Service is an organizational unit of the Italian Air Force (Servizio Meteorologico dell'Aeronautica Militare) and the national meteorological service in Italy. The weather forecasts and other services serve both the armed forces and the general public. of a severe heatwave dubbed Cerberus on the 13th. If you’ve ever been to Italy or abroad you’ll realise it’s usually a good idea to hide from the sun at this time of the day😉 As far as I can ascertain from observational data there was a short 3 day heatwave (see thermograph below) at Rome’s airport. The trouble with observational data from Italy, as is the case in the UK, you can only access a subset of it, and unfortunately Rome has only one SYNOPSYNOPSYNOP (surface synoptic observations) is a numerical code (called FM-12 by WMO) used for reporting weather observations made by manned and automated weather stations. SYNOP reports are typically mad hourly and consist of groups of numbers (and slashes where data is not available) describing general weather information, such as the temperature, barometric pressure and visibility at a weather station. station situated at the airport on the coast. Because of the HIEUHIUrban Heat Island (UHI) is an urban area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak. UHI is most noticeable during the summer and winter. The main cause of the UHI effect is from the modification of land surfaces I’m sure it was much warmer in the centre of Rome. Not only is there a shortage of observational data for many countries, I challenge you to find any up to date LTALTALong Term Average. This is usually defined as a 30 year period by the WMO. climate data for any of them either. What I mean here by up to date is the LTA for 1991-2020 and not that for 1971-2000 that I have for many stations. You would have thought in these days of “global boiling” the latest climate station for all member countries would be available on the WMOWMOThe World Meteorological Organisation is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics. website – no it isn’t – and if it wasn’t for Wikipedia, and some nifty parsing, I wouldn’t have collected over 800 LTA records across the world as I have. I’ve been watching and examining heatwaves closely across the UK and Europe since I retired from the Met OfficeUKMOThe 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 in 2011. There are no rules as to what constitutes a heatwave, and therein lies the problem. The UK have one set of rules and every other country has another, and that’s why I argued, mainly to myself because few people read what my views are or give a damn about them either, that instead of a rigid threshold for summer months of X°C for a region, as the UKMOUKMOThe 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 do, a “heatwave day” should be defined on the anomaly of the maximum temperature for each individual station. Over the years I’ve developed software and I usually default to an anomaly of 6°C above the LTA. Personally I think this is much too low for a severe heatwave, and probably should be ~+10°C. The thermograph for Seville shows the extent of the heatwave there using this 6°C rule. Three distinct heatwave days up to the 28th. These anomalies are calculated using the 1981-2010 LTA and not the much colder LTA of 1971-2000.
Seville 1981-2010 LTA
These thermographs for Rome, Decimomannu and Palermo use the 1971-2000 LTA. and because they anomalies calculated using this slightly colder LTA, the anomalies are much warmer than if I had the ones for 1991-2020. I’ve emailed METEOAM to see if I can obtain them, but am not hopeful I will be able to source the latest climate data. I shouldn’t need to do this, or rely on Wikipedia to supply them, this basic climatological data should be available from the WMO. That aside the three thermographs do highlight a series of heatwave days, with many as 15 at Decimomannu in Sardinia with an extreme maximum of 46.8°C.
I hope I’ve explained the importance of using the latest LTA for all stations to get an unbiased picture of July’s heatwave. The map below of total heatwave days shows the number of days with a maximum temperature anomaly of 6°C or higher. There’s no doubt that it was hot across a large of southeastern Europe using the +6°C threshold, particularly across parts of northern Algeria and Tunisia. There are what looks like spuriously high anomalies scattered around these are probably caused by out-of-date LTA.
Number of days with a maximum temperature [06-18] >=+6°C
If you look at the next chart this shows the total number of days with anomalies of +10°C or more, and what I maintain are severe heatwave days. Heatwaves in the UK must last at least three consecutive days or more before they can be officially labelled a heatwave, many of the sites in the chart below away from North Africa have one or two, and even if they have more they may not be consecutive.
Number of days with a maximum temperature [06-18] >=+10°C
Looking at reanalysis gridded temperatures and anomalies up to the 26th reveal what I think was really going on. The core of the heat was across the north of Algeria and Tunisia, occasionally some of that very hot air escaped transferring northwards from Africa to affect parts of Sardinia, Sicily, southern Italy, western Greece and the Balkans, and because SSTSSTSea Surface Temperatures temperatures in the Mediterranean were at record levels during July, the sea didn’t cool the air at the surface as much as it could. The other thing is the media got a hold of this story and ran with it, this was easy to do, because they already had stories about heatwaves in the southern states of America and China, and as the month went on wildfires broke out, and it was also announced that July was very likely to be the record hottest month – a perfect combination for catastrophising the whole thing🥵. For the record heatwaves don’t cause wildfires people do.
These two charts underline how warm June and sunny the June of 2023 was across the UKUKThe 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.. It set new extremes in most regions, but not everywhere.
It’s been the warmest June since at least 1884 in the north of Scotland by a massive 1.2°C😲 It’s hard to believe just how warm June 2023 was in the north of Scotland, particularly so because we now call it home. The warmest in at least 140 years by a big, big, margin.
It’s official, June 2023 was the warmest June since temperatures recorded started in 1884. Rather surprisingly it only came in as the fourth sunniest. Anomalies show that the north of Scotland was both the sunniest and warmest region in the UKUKThe 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. during June.
