A strange old month with some rapid switches in cyclonicity. Mostly zonal but an anticyclonic second week and three named storms. The Gale Index in the objective LWTLWTLamb 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. that I calculate from reanalysis data is not the same as the GIGIGale Index that I generate from 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.
Temperatures across 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. were close to average in January. I suspect the mean 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. chart is not telling us the full story, because with a mean flow like this, you might have expected temperatures to have been well above average.
If you turn up the granularity the pentad mean pressure charts reveals why January wasn’t much milder. The 7th to 11th was cold and anticyclonic, the 12th to 16th NW’ly and the 17th to 31st was a milder W or SW’ly.
January 2024 was the warmest on record globally in my DIYDIYDo It Yourself Global Temperature series. That makes it eight consecutive months of record global temperatures. It wasn’t by such as a wide margin as in some of the other months, the January mean of 9.15°C was just was just 0.03°C higher than that of 2016. The 365 day moving average is still skyrocketing as you can see in the chart below.
In January daily global temperatures have struggled to be the highest on record, vieing at times with January 2016 to be the warmest, no doubt due to the El NinoEl NiñoEl Niño 'The Boy' is the warm phase of the El Niño–Southern Oscillation and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific fading and helping to bring global temperatures back to some kind of normalcy after eight months of craziness.
The cause of the recent surge in global temperatures looks likely to have been the very high SSTSSTSea Surface Temperatures in the world’s oceans, led in no small part by El Nino in the central Pacific as you can see in this graph.
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
I might fill this article out with some extra detail when I get the time. At the moment I am watching the slow thaw of 10 inches of snow in StrathpefferStrathpefferStrathpeffer (Scottish Gaelic: Srath Pheofhair) is a village and spa town in Easter Ross, Highland, Scotland, with a population of 1,469. which I find very distracting and rather depressing 😪
It looks like this January (2024) could turn into a very anticyclonic month from this weekend, so I thought I would take a look back in the objective LWTLWTLamb 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. records, which started in 1871, and found that January 1992 was the most anticyclonic on record., although despite it being so anticyclonic, it never really managed to generate more than a few easterly days at the start of the third week.
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. that month 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. got close to 1050 hPahPaA Hectopascal is the SI unit of pressure and identical to the Millibar on the 26th as you can see from the chart for 12 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)., the highest on that chart was 1049.0 hPa at Cynwyd in Denbighshire. I only have main synoptic hour data so it may have broken through 1050 hPa. Notice that they’re also plotted 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. reports from Cape Wrath, Butt of Lewis and Binbrook on that chart, those were the days 😉
One other point about January 1992 is that it was also a El NinoEl NiñoEl Niño 'The Boy' is the warm phase of the El Niño–Southern Oscillation and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific month.
Here’s an interesting graph that compares 24 hour mean temperatures between Benson in Oxfordshire and Loch Glascarnoch in the Highlands, and which highlights the differences between the cold frosty continental conditions in the south and the much milder Atlantic air across the north during the fourth week.
Temperatures were close to average in the north of Scotland during January, but it was a little duller than average (84%), with precipitation close to average (96%). I’m not at all convinced that the AWSAWSAutomatic Weather Station rain gauges in our part of the Highlands picked up and melted all the snow they collected during the snowy spell in the third week though.
