UKMO

Altnaharra forecast temperature verification

5th – 11th January 2025
Altnaharra
3 hour forecast temperature verification
Data 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 Weather App

I doubt if you’ll ever see a temperature forecast as way out as this one got. It was issued by 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 in their weather app on the 5th of January for Altnaharra in Sutherland. The blue line in the top chart shows three hourly forecast temperatures for the next seven days. The red filled area shows air temperatures taken from AWSAWS Automatic Weather Station observations for Altnaharra. The lower bar chart, shows the difference between the forecast and the observed. Although the forecast for the 7th to the 9th was reasonably accurate, the 10th and 11th got progressively worse, with forecast temperatures being as much as 20°C too high at one point. I’m not sure what NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. model the Met Office use for these site specific forecasts, but it has got some severe problems, and not just with record cold temperatures I might add.

January 12, 2025

Forecasts, UKMO, Weather Apps

Altnaharra forecast temperature verification Read More »

Prebaratic Charts

I first came across the term ‘prebaratic’ or ‘prebar’ when I joined 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 in 1970 as an assistant. To me the term was synonymous with the ‘T+24 forecast chart’ which we received at outstations by MOLFAXMOLFAX An early type of fax machine using wet paper.* from Bracknell every six hours. I never realised until now that ‘prebaratic’ was a rather crude acronym for “barometric pressure distribution over the Atlantic” until I read this in the 1956 book ‘Weather Map’. It’s hard to believe that these prebaratic charts were the very forecast charts which we take for granted these days.

* This is a MOLFAX recorder which was an essential piece of equipment at outstations. This is an image of a MUFAX machine made by MUirehead. I’m sure we didn’t call it MUFAX back then, but MOLFAX, don’t ask me what that acronym stood for, but you can be sure Met Office was in there somewhere. The Met Office have always been good at inventing acronyms. 😉

January 9, 2025

Forecasts, UKMO

Prebaratic Charts Read More »

How are we doing with the forecast for winter 2024-25 [DJF]?

We’re getting onto halfway through winter now, and I wondered just how well 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 were doing with their forecast for this winter they issued on the 25 November 2024.
Well, mean temperatures are +0.7°C above average, that’s despite the ongoing cold spell, but not as mild as the 45% on the mild side of average suggests, so 6/10.
Total rainfall also looks higher than average, and higher than forecast with all these flood alerts around at the moment. December was rather dry, particularly in the S, but a forecast of 30% on the wet side of average still looks a little too low, so maybe only 8/10 for that.
The UKMO provide no LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO. for wind speed that I can find to calculate anomalies with, and surprisingly they don’t forecast sunshine, which is pretty important for the nations vitamin D3 levels. 😎

January 7, 2025

Long Range Forecast, UKMO, Winter

How are we doing with the forecast for winter 2024-25 [DJF]? Read More »

UKMO 3 Month Outlook – Autumn 2024 verification

I thought that I’d look back at the three month outlook for autumn 2024 [SONSON Meteorological Autumn - September, October and November] issued by 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 on the 27 August. The outlook is split into three distinct areas, temperature, precipitation and wind speed. It’s relatively easy to assess how accurate the outlook was for temperature and precipitation, but not so for wind because the UKMO don’t issue monthly gridded mean wind speed data. They must have this data because the three month outlook itself contain three month anomaly charts for wind speed. The one climate statistic that they did omit is sunshine, important not only summer, but also in autumn and winter, as this gloomy November highlighted only too well. Here’s a table of climate statistics 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. for the three months that make up meteorological autumn and anomalies for temperature, precipitation and sunshine.

How accurate was the forecast of temperatures?

The outlook stated that there was a 40% chance of it being a warm autumn, with a fifty-fifty chance of near average temperatures. In the end, the mean temperature for the three months that make up meteorological autumn was +0.3°C above the 1991-2020 long-term average, so it was only marginally warmer. WRONG, autumn was not noticeably warmer than average, although they were right about ‘cool spells’ later in the season, but cold spells towards the end of autumn are far from uncommon.😉

How accurate was the forecast of precipitation?

The outlook stated that there was a 35% chance of autumn being wet, with a 55% of it being near average. In the end precipitation in autumn 2024 ended up 89% of the long-term average. So a drier, rather than a wetter autumn. Despite flooding from storm Bert, the first half of November was very dry across the whole country, WRONG.

How accurate was the forecast of mean wind speed?

The outlook stated that there was a 35% chance of autumn being windier than average, with an increased risk of stormy conditions. As I said earlier, there’s not an easy way of measuring the accuracy of this one. There were three named storms during autumn, one of them named by the KNMI, the other by Met EireannMet Éireann Met Éireann, the Irish National Meteorological Service, is the leading provider of weather information and related services for Ireland.. The first half of November was anticyclonic which would have reduced the mean speed for the whole of autumn a fair bit. UNDECIDED.

December 2, 2024

Autumn, Long Range Forecast, UKMO

UKMO 3 Month Outlook – Autumn 2024 verification Read More »

England Wales Precipitation – Seasonal Trends since 1766

The long-running England & Wales Precipitation [EWPEWP The England Wales Precipitation series began in 1766 and is the longest instrumental series of this kind in the world.] series began in 1766, and is the longest instrumental series of this kind in the world. It’s part of the HadUKP series of datasets of 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. regional precipitation. Here are five charts of seasonal and annual totals from 1766 to 2024. To each of them I’ve added a 10 year centred moving average, along with a linear trend from 1766 to 2024. Data for Autumn 2024 isn’t in yet, but I’ll update it when it has. Basically in the last 258 years precipitation across England and Wales:-

Winters have got a much wetter up from 198 mm to 276 mm (+39.4%)
Springs have got rather wetter up from 175 mm to 195 mm (+11.5%)
Summers have got drier down from 245 mm to 212 mm (-13.6%)
Winters have got a little drier down from 273 mm to 268 mm (-1.9%)
Annually things have got wetter from 890 mm to 952 mm (+6.9%)

November 29, 2024

Climate, EWP, Precipitation

England Wales Precipitation – Seasonal Trends since 1766 Read More »

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.

November 2, 2024

Analysis, October, UKMO

Oct 2024 – Weather Log Read More »

Wind speeds from Buoys and Weatherships

I’ll warn you now this is a crazy post 😜. For some reason I got to wondering how much of an affect the friction from a stormy sea with large winds a big swell and large waves can have on wind speeds measured by an anemometer out in the open ocean? The reason I ask is because in the recent named storm ‘Ashley’ on the 20th of October 2024, the winds from the Weather Buoy known as K4, seemed to be rather on the low side. My memory is probably playing tricks here, but I remember when plotting any of the Ocean Weather Ships on a chart in stormy weather as an assistant, it wasn’t unusual for me to plot mean speeds of 50 knots or more. That’s when I got to wondering about surface friction and the height of the anemometer, and what effect friction would have on wind speeds? The height of the anemometer may have been 60 feet or more above the ocean surface on a weathership, but on a weather buoy, that might be no more than 20 feet. It may be fairly academic now because the days of weather ships have long since passed, but there are still hundreds of ship and probably thousands of weather buoys observations made each hour across the world, so I wonder if any adjustment at all is made to those from buoys? I did warn you that this post was crazy.😉

PS If you want to find out more about Ocean Weather Ships maintained by 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 Ican recommend this great site WeatherShips.com

October 20, 2024

Ocean Weather Ships, Oceans, Software, Wind

Wind speeds from Buoys and Weatherships Read More »

Lamb Weather Types and UKP correlations

I had previously plotted correlations between LWTLWT Lamb Weather Types are often used in UK-based analyses, with individual weather patterns based on the eight primary cardinal directions (N, NE, E, SE, S, SW, W, NW) plus cyclonic (C), anticyclonic (A) and unclassified (U) types. and CETCET Central England Temperature, so the obvious thing to do now was to plot correlation charts using daily LWT types and daily rainfall from the UKPUKP UKP is a gridded datasets of UK regional precipitation. regional rainfall series, which I download 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. It turned out to be even less exciting than a lot of the climate statistics I’ve produced before, in that it just confirmed what you could easily deduce by using a little common sense in that anticyclonic weather types are drier than cyclonic types. 🙂
Generally westerly types come in second wettest, using an average for the whole year.
Depending on what region you look at, easterly & northerly types are sometimes drier than anticyclonic types. The reason for that is that the results are likely skewed for easterly and northerly types because they occur much less frequently than do anticyclonic types.
Westerly types in Scotland (see below) seem to peak in January, at close to 2 mm per day, but fall to a low of 0.4 mm in May, again a fairly obvious correlation.

October 8, 2024

Correlations, LWT, UKP

Lamb Weather Types and UKP correlations Read More »

Was the cool unsettled start to July anticipated?

16-30 day 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 text forecast

Was the cold and unsettled start to July in anyway expected by the UKMO in their long range (16-30 day) forecast? As far as colder than average temperatures are concerned that’s a definite no, with mean anomalies for the period from 29 June to the 12th of July between one and three degrees below the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.. There was no mention of such a dull start to the month either, with sunshine widely only 60% or less of the LTA. Sunshine may have been in short supply but rainfall totals were widely above average in the 14 day period, with large areas seeing totals 200% or more of the LTA. So the short answer to the question, as measured by mean temperature, total sunshine and rainfall, is a most definite no, the cool, dull and wet start to July was not anticipated.😜

^{Double click to show enlarged slide show}

July 13, 2024

Long Range Forecast, UKMO

Was the cool unsettled start to July anticipated? Read More »

Latest NAO-CET-UKP

I’ve just refreshed the three graphs in an application I use to calculate a simple NAONAO The North Atlantic Oscillation (NAO) is a weather phenomenon over the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High. Through fluctuations in the strength of the Icelandic Low and the Azores High, it controls the strength and direction of westerly winds and location of storm tracks across the North Atlantic. index with from gridded 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. data I download from NOAANOAA NOAA is an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; provides weather reports and forecasts floods and hurricanes and other natural disasters related to weather.. We still await a second major NAO event in 2024 that will hopefully break the prolonged spell of mobile and cyclonic weather we’ve been experiencing since the middle of January. Maybe this anticyclone over 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. forecast for this weekend will be the start of it. 🤨

Met Office App – Forecast Temperature Verification

I download the site specific NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. data that resides in the HTML 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 weather application requests whenever anyone looks for a forecast for a location for a number of my applications I’ve written to visualise the forecast data in a table, graph or on a map. Parsing the data was a tricky business, but I persevered, and can now grab a week of one and the three hourly data for any number of elements including temperature.
As well as visualising the data, I thought it might be interesting to do a spot of forecast verification by comparing the three hourly forecast data with the actual values from 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. observation for any location in the world.
I know that the forecast values although quite accurate, are far from being spot on. The question I was intrigued to find out was just how accurate they are. Here are some recent preliminary results I have produced from the add-on to my 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 NWP application I wrote a number of years ago.

Notice the very warm day on the 6th of April associated with storm Kathleen, and how underestimated temperatures at Kinloss were because of a slight 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. effect.

Generally a pretty good result with temperatures +/- 2°C at Heathrow.

Again at Exeter temperatures within +/- 2°C of the forecast, although it didn’t do well with some of the minima, and the 8th of April was a bit of a disaster because heavy rain suppressed temperatures.

I’ve noticed that recently the Met Office are in the process of updating the NWP data their app uses, so they must have some concerns themselves about its accuracy, although the changes in the NWP might have more to do with forecast weather, rather than forecast temperatures. At the moment I am still using the old data and haven’t switched to the new trial data. In the meantime, let me know about what you think about the accuracy of the forecasts the Weather App produces in your area. I’ve still got a bit more testing, tweaking and bug fixes to do to my verification application, but I’ll keep you posted.😉

UKP – 365 day totals

The 365 day UKPUKP UKP is a gridded datasets of UK regional precipitation. total precipitation for Central England is still at record levels (149.9% of the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.) at the end of February 2024, as are the totals in the Northwest, Northeast & Southeast regions of England. Northern Scotland is the driest region and continues to run close to average as it’s done for the last year or more. We passed Loch Glascarnoch earlier this week on our way to Ullapool and I have never seen it as full as it is.

UKP – Running at record high levels

The 365 day UKPUKP UKP is a gridded datasets of UK regional precipitation. regional precipitation totals are running at record high levels at the moment. Never since the start of the gridded daily records in 1931 have 365 day totals been as high as they are on the 23 February 2024 for Central England, Eastern Scotland, Northern Ireland and England Wales. Anomalies for Central England for example are at 149.3% of the 1981-2010 LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.. Hopefully I’ve got all my maths and my coding right 😉

The red ringed cells mark the highest 365 day totals for this region.

Northern Scotland still has the lowest 365 day anomaly (105.2%).

North Atlantic Oscillation – A simple version

I reworked an old application last week that I use to generate a simple six hourly North Atlantic Oscillation from 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. reanalysis data that I download. It’s simple, nothing complicated using geopotential heights at 500 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar or anything like that, just the pressure difference between 65N 25W and 37.5N 25W. A well as plotting the NAONAO The North Atlantic Oscillation (NAO) is a weather phenomenon over the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High. Through fluctuations in the strength of the Icelandic Low and the Azores High, it controls the strength and direction of westerly winds and location of storm tracks across the North Atlantic. I also add charts of the daily mean anomaly from the CETCET Central England Temperature series, along with the England Wales rainfall from the daily UKPUKP UKP is a gridded datasets of UK regional precipitation. series, both of which I download 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. As you can see in winter at least there is a strong correlation between the NAO and CET & UKP. I’ll add more viewers to examine the correlation, so much to do, and so little time, as the Joker said.

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.

The continuing saga of the missing Tórshavn observation

^{_{14 Jan 2024 1400 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).
Replete with the observation for 06010}}

Anyone who loves 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 as much as I do, and likes a plotted chart of NW Europe, will bemoan the missing SYNOP observation from Tórshavn. It’s been missing for a good number of years now, and leaves a big hole in a plotted surface chart between Scotland and Iceland. It’s akin to 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 decision to run just one radiosonde station in Scotland, the demise of Stornoway and at Shanwell leave a similar gap in the upper air coverage across the north 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. too.
My running joke on the missing 06011 SYNOP is that the WMOWMO The World Meteorological Organisation is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics. should shellout on buying a Vantage Pro AWSAWS Automatic Weather Station and just gift it to DMIDMI The Danish Meteorological Institute is the national meteorological service for Denmark and Greenland. so the Faroese could install it in the capital Tórshavn. It’s not that the Faroese are shy of technology, a good number of it’s 18 islands are now connected by undersea tunnels, which also boast the world’s first undersea roundabout, so they do know a thing or two about engineering, but seem to have very little interest in monitoring the weather.
Anyway what I’ve done today is simple enough, I just wrote a new procedure to download the latest METARMETAR METAR is a format for reporting weather information. A METAR weather report is predominantly used by aircraft pilots, and by meteorologists, who use aggregated METAR information to assist in weather forecasting. Raw METAR is the most common format in the world for the transmission of observational weather data. from Vágar, the islands only airport. The ICAO is EKVG, and it’s associated WMO number is 06010. Instead of fetching the METAR from OGIMET, I download it from the ADDs server run by NOAANOAA NOAA is an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; provides weather reports and forecasts floods and hurricanes and other natural disasters related to weather. in America. I can now at a click of button fill the big gap with pseudo SYNOP complete with QNH parsed from the METAR. It’s pure idleness on my part why I didn’t add this functionality many years ago to my old SYNOP application.

UKP: Latest regional 365 day totals

1 Jun 2022-31 May 2023 Regional UKPUKP UKP is a gridded datasets of UK regional precipitation. 365 day precipitation POAPOA Percentage Of Average

The dry last three weeks have already had a noticeable effect on the 365 day percentage of LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.. Northern Scotland is now the driest, instead of being one of the wettest regions.