Oct 2024 – Weather Log
There is only one chart in the whole month that doesn’t include a front of some kind in it. Spot the days when Mr Occlusion was on shift down at Exeter, the 9th is total nonsense.
Oct 2024 – Weather Log Read More »
Analysis
16 Oct 1987 – The Great Storm
Only three hourly Synops I’m afraid, and many of them missing from the worst affected regions. At a glance, and from this limited SYNOPSYNOP SYNOP (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. data, although it looked a pretty windy night, you wouldn’t have thought it had been as severe as it was across the southeast of England. I’ve no idea if my hind sight analysis was anywhere close to the analysis on the day. I was an observer at Kinloss at the time, and missed all the excitement after being posted to Scotland that summer.
16 Oct 1987 – The Great Storm Read More »
3 Feb 2024 | UKMO shoddy analysis
I just had to make a record of these tweets I’ve made yesterday evening and today concerning a series of 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 analysis over the last 24 hours. They include triple warm sectors, non-existent cold fronts, and an existing active cold front that was marked frontogenetic at 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). and frontolysingFrontolysis Frontolysis in meteorology, is the dissipation or weakening of an atmospheric front. at 18 UTC. Maybe the fronts are added automatically by AIAI Artificial intelligence is intelligence - perceiving, synthesizing, and inferring information - demonstrated by machines, as opposed to intelligence displayed by animals and humans. these days? If they’re added manually there’s really no excuse, because this is just basic meteorology and watching the observations.
3 Feb 2024 | UKMO shoddy analysis Read More »
How to recreate a plotted weather chart for January 1963 with observations from the Daily Weather Report
How to recreate plotted weather charts with observations from the Daily Weather Report – yes it’s a bit of a mouthful as titles go but it’s what I’ve done over the Christmas holidays. The Daily Weather Reports [DWR] in question are the ones that 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 have very kindly scanned and made available on their website. The daily reports extend back to September of 1860, but for a start I’m only interested in the years from around 1960 to 1972, after that I have my own 6 hourly observational data that I bought from Weather Graphics some years ago and have kept updated by means of OGIMET in recent years. So if you want interested at looking at a plotted synoptic chart for a particular day from January 1963, you could approach the Met Office and ask them to provide you with all the SYNOPSYNOP SYNOP (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 for the hour that you’re interested in, I haven’t done that personally, because I think the cost would be prohibitive. But there is another way, and that’s to download the PDFPDF Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992. of the DWR for January 1963 and extract the 55 observations that are contained within it and plot your own chart, and that’s exactly what I did:
- Download the PDF of the DWR for the month of January 1963 from the Met Office (~67 MB).
- Cut and paste the observations for the hour that you are interested in (00, 06, 12 or 18) as a JPEG from the PDF.
- Use a good OCR application to create a text file from the JPEG.
- Write an application to allow you to edit the text file returned by the OCR application to verify and edit each observation.
- Use the application to convert the old format SYNOP into the new format.
- Download the reanalysis MSLPMSLP Mean 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. pressure data for 1963 (~19 MB) from the NCEPNCEP The United States National Centers for Environmental Prediction (NCEP) delivers national and global weather, water, climate and space weather guidance, forecasts, warnings and analyses to its Partners and External User Communities. site, convert the NetCDF format into plain text using NCDUMP, parse that gridded text into individual MSLP data files for each main synoptic hour for that year.
- Inject the MSLP 2.5° x 2.5° gridded data values for 18 UTC on the 2nd of January 1963 from the data file you created in step 6 as a background field to improve the MSLP contouring, along with all the SYNOP observations that you created in step 5 into your SYNOP viewer, ensuring that you have all the locations of the old observing sites (such as Spurn Head and Cape Wrath) in your stations database so you can plot them!
- Generate a screenshot of the British Isles for 18 UTC and add it into you blog.
And that my friends, is all there is to it.
Optical Character Recognition
I have found one thing from this exercise and that OCR software is not a great deal better than it was 20 years ago when I first used it. None of the free and online OCR web services work at all well, and none of them allowed you to choose numeric only input. Some of the results were so bad that the numeric results have been converted into the equivalent of a piece of Shakespeare in the Infinite monkey theorem! I tried to sharpen and reduce the number of colours to no avail, I cut and pasted and saved as high quality JPEG, PNG, TIFFTIFF Tag Image File Format, abbreviated TIFF or TIF, is an image file format for storing raster graphics images. and PDF without any improvement in character recognition. Just at the point of giving it all up as a bad job I decided to download a trial of Abbyy PDF Creator+ and at first found the results were equally as poor, until I noticed that if I set the language to digits the results were very much better, probably around 90% of the numeric characters in the observations were now correct.
The final result
And so here is the finished product (fig 2), more than 60 years after the observations were made. I was still a little young to be involved with making one of the 55 observations quite yet, but I did spot a typo in the original DWR, it occurred in the 03715 Rhoose observation, and although I would for a bit of fun like to submit a correction to it to the Met Office help desk, they’d probably not see the funny side of it 60 years after the event as I do!
Of course the perfect answer to my conundrum would be for the Met Office to make all their archived SYNOP observations freely accessible, but I don’t see that happening anytime soon, but if you’re as daft as I am, and follow the steps that I’ve outlined above, you too could step back in time and recreate a plotted weather chart from the 1960’s.
2nd January 1962 18 UTC – courtesy of the Met Office and Crown Copyright
18 UTC 2 January 1963 – courtesy of NCEP reanalysis
2 August 2023 – How unseasonable is Wednesday’s low?
Well the first thing to say is that low’s are not at all unusual in August. Remember the Fasnet storm of 13 August 1979? Tomorrow’s low has a forecast central pressure of 983 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar for midday and is situated close to Birmingham. Below is a graphic of charts drawn using reanalysis data from 1948 so you can make your own minds up. The one that immediately stands out to me is the chart for the 2nd of August 1986, with a GIGI Gale Index of 38. Remember this chart uses reanalysis data in a coarse 2.5°x2.5° grid of MSLPMSLP Mean 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. values so contours may well be lower.
It just so happens that I have this chart, but as you can see the low close to Tiree is already a filling feature, with a minimum central pressure of 988 hPa at 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)., and can’t match the forecast depth of tomorrow’s low. So tomorrow’s low looks very unusual, and is likely the deepest low to affect 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. on this date in over 75 years!
2 August 2023 – How unseasonable is Wednesday’s low? Read More »
When is a quasi-stationary front not a quasi-stationary front?
Q: When is a quasi-stationary front not a quasi-stationary front?
A: When it’s still moving.
A quasi-stationary front can’t straddle the isobaric flow like this one does over the Borders in this 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 Analysis. For it to be quasi-stationary, it has to be truly “stationary”, and the front itself run parallel to the isobars. This front was originally a section of a cold front heading SE across Scotland, but it’s now a returning warm front that’s now heading westward.
When is a quasi-stationary front not a quasi-stationary front? Read More »
They say lows Don’t like mountains
It was interesting to see how the deepening low on the 14th of January lept from the Atlantic ocean into the North sea in one bound as it headed eastward towards southern Norway. I do vaguely remember being told many moons ago how low pressure systems don’t like navigating over mountain blocks such as the NW Highlands. That may be an apocryphal story but that’s what seemed to happen yesterday.
They say lows Don’t like mountains Read More »
27 Dec 2022 – 06 UTC analysis
Dear Diary
For a change we have had four centimetres of fluffy snow overnight, everywhere is white including the A834, and it’s -2°C here in the Strath this morning. Some of the ice that survived the cold spell from earlier in the month survived to see it. I am now firmly of the opinion that the climate of a Scottish glen is more akin to that of southern Norway during December and January when the sun is very low.
27 Dec 2022 – 06 UTC analysis Read More »
Christmas Past
To follow up the grid of analysis charts from 1998 to 2022 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 in the last post, I thought I would build a grid of reanalysis charts for Christmas day from 1836 to 2015.
Christmas Days 1998-2022
You can see how over the last 25 years the analysis from the UKMO has got more and more complicated. This is more than likely due to the fact that the analysis is now done using NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. fields and improved satellite imagery, rather than just surface observations anymore. It’s also shows the influence of Mr Occlusion over the last five years or so. Christmas day itself is usually a mobile affair and sometimes very cyclonic (1999 & 2013). Now and then its anticyclone (2006, 2008 & 2010) and one or two where its blocked (2009 & 2021). Just a rather cyclonic and boring SW’ly once again in 2022.
Christmas Days 1998-2022 Read More »
Cold wave across North America
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). analysis
Dear Diary
A lot of sensational reporting going on in the media about the low that’s been undergoing cyclogenesis in the eastern parts of the Great Lakes today, and the cold wave that’s introducing Arctic air across much of North America in its wake, as the low tracks NENE North East’ward into Canada. 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. News seems content to report temperatures in degrees Fahrenheit, perhaps because it makes the negative numbers even larger. Here are a few of the phrases that I’ve picked up from the BBC reports.
- Weather Bomb
- Bomb cyclone
- Flash freezing
- Brutal cold
The cold front has certainly dropped temperatures as it’s raced through. In my experience wind chills of -40°C or lower are very severe, but far from unprecedented across North America, and ones like this usually occur in most winters, but what the hell do I know. Another thing I don’t know is if the NWSNWS National weather service definition, an agency of the National Oceanic and Atmospheric Administration that is responsible for meteorological observations. has named the culprit low, perhaps it has descended into the realms of lunacy as most of its European counterpart Met Services have.
12 UTC wind chill
Cold wave across North America Read More »
23 Dec 2022 – 09 UTC analysis
Dear Diary
I would like to think there’s a broad warm sector across the SW and northern France but it might be just a warm occlusion. My cold front is not really supported by satellite imagery, but what the hell, it’s just between you and me diary.
23 Dec 2022 – 09 UTC analysis Read More »
22 Dec 2022 – Analysis 10 UTC
Dear Diary
Not too difficult to do an analysis on the 10 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). chart with a beautiful satellite image like this one to help. The first dry and bright morning since Saturday up here in the Highlands.
Lets see what the professionals made of it at 06 UTC down at EX1.
Despite these two analyses being just fours apart, It’s quite interesting to see their take on the analysis. No warm sector to explain the conditions across southern England like I have, Mr Occlusion has lived up to his name and has just thrown in an occlusion across the SW of England to explain that away. The occlusion they’ve drawn W-E across Shetland is there to mark the boundary between the sub 528 dm air to the north and the milder air across Scotland (dewpoints of 1 or2°C) I suppose, so why not just call it a ‘cold’ front?
22 Dec 2022 – Analysis 10 UTC Read More »
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?
Cold front makes slow progress Read More »
Wed, 7 Dec 2022 – 09 UTC analysis
Dear Diary
Not feeling particularly cold this morning 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. with temperatures close to 3°C. No measurable rain since the second of the month, but a few spots of rain in what little wind there is this morning. There’s a coating of snow on Ben Wyvis, but nothing down here in the strath. Hoping for something from this second cold front later this afternoon, but not counting on it.
Wed, 7 Dec 2022 – 09 UTC analysis Read More »
6 Dec 2020 – 09 UTC analysis
Dear Diary,
The cold front seems to have been taking it’s time moving south in the last 24 hours. Mondays chart.
6 Dec 2020 – 09 UTC analysis Read More »
November 2022
I’m sure that there should have been at least one named storm across 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. in such a windy month as November 2022 was. Even the French managed to come up with one – storm Claudio (31 October – 2 November).
5 December 2022 – 09 UTC analysis
Dear Diary,
The first rather modest signs of the much heralded colder weather arriving in the Shetlands this morning.
The cloud from front this will thwart the frost we might have seen tonight, instead of low cloud from the east, it’ll be low cloud from the north.
Sometimes you forget that you’re on an island and the weather is dominated by the sea.
Temperatures did their usual trick in the strath overnight: 0.1°C at midnight with clear skies, winds back into the east and low cloud rolls up the Cromarty Firth turning it cloudy, temperatures rise to 2°C at dawn, skies clear again as the wind backs more to the north, temperatures fall back to 1°C by 10am. This is a very common occurrence here and must be at least the third occasion it’s happened this Autumn.
5 December 2022 – 09 UTC analysis Read More »
Mediterranean Analysis 26 Nov
I bet Inspector Montalbano missed his daily swim this morning
Mediterranean Analysis 26 Nov Read More »
12 UTC analysis
There may well have been a mini-tornado in Wales this morning, but the highest guts from the stations in the SYNOPSYNOP SYNOP (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. network are rather underwhelming, and none of them higher than the 76 mph gust at the Mumbles yesterday when there was no yellow warning in force. Line convection on a cold front like we’ve seen today is not an uncommon occurrence across 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. at any time of the year, but does that mean from now on we’ll see 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 issue a combined Yellow warning for heavy rain and strong winds each time that they do?
13 UTC – 19 November 2022
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. tantalisingly close and edging into East Anglia this afternoon.
13 UTC – 19 November 2022 Read More »