Accuracy of Long range Forecasts from UKMO

I’ve been archiving text LRFLRF Long Range Forecast. Usually 16 to 30 days or more. 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 for a month or two now so I thought I would take a look and see just how accurate they’ve been. The recent cold and snowy start to March 2023 seemed a perfect period to evaluate, so here is the text for the 16-30 day forecast issued on the 9th of February, and the 6-15 day forecast issued on the 24 February.

16-30 Day

The ‘bands of rain and strong winds… in the northwest’ in the 16-30 day forecast is clearly wrong, and looked so even when it was first published on the 9th of February. An intense high persisted over N Scotland from the 26th of February to the 4th of March. The ‘low probability of some much colder weather’ is also clearly far from accurate and really should if anything have read ‘high’.

6-15 Day

‘There is also potential for a spell of more unsettled weather in the far north again this is inaccurate. The weather types in the N of Scotland during this period was either A or AN, and the two unsettled spells that did occur were associated with lows that crossed the country much further south than the N of Scotland. ‘A low chance of more organised rain or snow spreading south’ is another faux pas with many areas across N Ireland, N Wales and N England seeing a spell of heavy snow on the 9/10 February. ‘Temperatures generally on the colder side of average’ is partly correct, but anomalies for the 1-10 February were generally between -2°C to -3°C below the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO. 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. with Altnaharra recording two consecutive nights with minima of -15.4°C and -16°C, the coldest March nights since 2010.

Summary

The accuracy of NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. forecasts beyond T+120, sometimes T+96 takes a nosedive, so I don’t know why I should think LRF can be in anyway be more than vaguely accurate. My main complaint with it is the lack of consistency in how they’re written, and the fact that the 16-30 day forecast can remain the same for as long as a week at a time, which can’t be right.

Long Range Forecast

Accuracy of Long range Forecasts from UKMO Read More »

Winter [DJF] 2022-23 Frost

A map of air frosts, ground frosts and ice days in the meteorological winter of 2022-23. Remarkably there were more air frosts at Benson in Oxfordshire than there were at Aviemore in the Highlands. I should make an effort to compare these results with a 30 year average but I don’t have the time to compile the stats for each station at the moment. Don’t forget to click an image to enlarge it. Here for completeness is the thermograph for Benson to prove just what a cold hole it is.

Frost, Winter

Winter [DJF] 2022-23 Frost Read More »

Winter [DJF] 2023 – Objective LWT

I see there’s talk about how this winter has seen no named storms 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 and it’s friends. That’s because the naming of storms is a subjective based system based on impact based warnings system, at least in 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.. True, it has been a quieter winter than average, especially in the first half of December, but that doesnt mean there’s been a shortage of candidates for named storms, but because nearly all only affected the north of Scotland and require the issuance of an amber warning, i.e. gusts of 90 mph or more, this didn’t happen. If the UKMO wanted, it could easily create an objective system based on regional NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. data, then I think then, people might take it more seriously.

LWT, Named Storms

Winter [DJF] 2023 – Objective LWT Read More »

February 2023 – Global Temperatures

Global temperatures in February 2023 in my DIYDIY Do It Yourself Global temperature’s series were the fourth warmest since 1948. The 365 day mean temperature (see below), after flatlining since last spring is also showing signs of surging upwards despite the ongoing La NinaLa Niña La Niña is an oceanic and atmospheric phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation climate pattern. The name La Niña originates from Spanish for "the girl", by analogy to El Niño, meaning "the boy". In the past, it was also called an anti-El Niño[1] and El Viejo, meaning "the old man." trying to keep it in check.

The main driver behind this nascent surge in global temperatures seems to be rapid warming in the last few months of the northern subtropics despite a continued fall in temperatures at the tropics fueled by ENSOENSO El Niño–Southern Oscillation is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña.. This is the third surge in temperatures in the northern subtropics in recent years, the others were in 2016 and 2020, but the magnitude of this one might top them both despite the recent SSWSSW A sudden stratospheric warming (SSW) is an event in which polar stratospheric temperatures rise by as much as 50 °C in the course of a few days. The warming is preceded by a slowing then reversal of the westerly winds in the stratospheric polar vortex. SSWs occur about six times per decade in the northern hemisphere, and about once every 20-30 years in the southern hemisphere. event.

February, Global Temperatures

February 2023 – Global Temperatures 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.

https://wikiwand.com/en/Stationary_front…

Analysis

When is a quasi-stationary front not a quasi-stationary front? Read More »

Weather patterns may lead to flooding in February, Met Office warns

Courtesy of The Guardian

February 2023 is likely to be the fifth driest February since 1931 using gridded data for England and Wales 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, and in central England it could well be the second driest. It’s been drier than average thanks to persistent high pressure, which although not uncommon in February, is not usually as long lasting as its been this year.

I can see how the Guardian used Will Lang, head of situational awareness at the UKMO, to manipulate another climate extremes scare story back in November. Yes it was significant at the time that the three-month forecast had not reached February yet, but I think we read far too much into tele-connections such as the QBOQBO The quasi-biennial oscillation (QBO) is a quasiperiodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found., 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., AOAO The Arctic oscillation (AO) or Northern Annular Mode/Northern Hemisphere Annular Mode (NAM) is a weather phenomenon at the Arctic pole north of 20 degrees latitude. It is an important mode of climate variability for the Northern Hemisphere. The southern hemisphere analogue is called the Antarctic oscillation or Southern Annular Mode (SAM). The index varies over time with no particular periodicity, and is characterized by non-seasonal sea-level pressure anomalies of one sign in the Arctic, balanced by anomalies of opposite sign centered at about 37–45° N., ENSOENSO El Niño–Southern Oscillation is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. and of course the SSWSSW A sudden stratospheric warming (SSW) is an event in which polar stratospheric temperatures rise by as much as 50 °C in the course of a few days. The warming is preceded by a slowing then reversal of the westerly winds in the stratospheric polar vortex. SSWs occur about six times per decade in the northern hemisphere, and about once every 20-30 years in the southern hemisphere., these days, thinking we are anywhere close to understanding the complexities of our global weather system, and this Guardian story illustrates this fact perfectly. The threat of flooding has not gone away, but it’s likely that it’ll be the lack of rainfall that will dominate the weather news across Europe this coming spring and summer.

Climate, ENSO, SSW

Weather patterns may lead to flooding in February, Met Office warns Read More »

February 2023 exceptionally anticyclonic?

Don’t get the idea that the positive 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. anomalies across the SW of England of +13.8 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar so far this February are in anyway exceptional – on looking at all February’s back to 1948 using reanalysis data, I think I can safely say it’s not. Put it down to my naivety, I never realised just how varied the month of February, or any month for that matter, can be in 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.. Take a look at the very anticyclonic nature and anomalies of Februaries in 1959 and 2012 are for example, or the anomalies and AEAE Anticyclonic Easterly of 1986, but there I’m straying off topic.

February, Pressure

February 2023 exceptionally anticyclonic? Read More »

zoom.earth

zoom.earth

I just came across a Windy look alike web weather app this morning. If you don’t mind the ads it looks quite good, and although It seems to be a little short on NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. fields, its quick and offers hi-res satellite and a full spread of European radar.

Weather Apps

zoom.earth Read More »

NOAA GlobalTemp v5.1

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. have just updated their global temperatures series. The latest version, version 5.1 differs from 5.0 in two major ways:  

  • 5.1 extends back to 1850 (vs. 1880)
  • 5.1 has complete coverage of all land and ocean areas for the entire period of record

This chart extends back to 1950 shows the monthly anomalies coloured by the ENSOENSO El Niño–Southern Oscillation is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. status for that month. As you can see it’s not written in stone that a a La NinaLa Niña La Niña is an oceanic and atmospheric phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation climate pattern. The name La Niña originates from Spanish for "the girl", by analogy to El Niño, meaning "the boy". In the past, it was also called an anti-El Niño[1] and El Viejo, meaning "the old man." event coincides with low anomalies, or that an El NinoEl Niño El 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 event coincides with all the warm spikes in global monthly anomalies either.

ENSO, Global Temperatures

NOAA GlobalTemp v5.1 Read More »

17 February 2023 – Storm Otto

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). Analysis

Storm Otto was named by the DMIDMI The Danish Meteorological Institute is the national meteorological service for Denmark and Greenland. because 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 refused to issue an amber warning for strong winds for Scotland on Wednesday (15th). That left the way open for the DMI to step in and claim the storm as their own, despite the strength of the wind across Denmark in the afternoon being no stronger than it was in the early morning across the north and east of Scotland or northeast England. I have no idea what’s going on down at Exeter, but they certainly seem to have it fixed in their heads that amber warnings will only be issued for Scotland if wind speed exceed 90 mph, and because amber warnings trigger the naming of storms, that, and persistent high pressure in the south, is the reason why there’s been a paucity of them this autumn and winter 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..

Strongest Gusts
Lossiemouth Anemograph
DMI, Named Storms, UKMO

17 February 2023 – Storm Otto Read More »

Infamy, infamy they’ve all got it in for me…

I can’t help but think that anyone who can turn heavy winter rainfall and severe flooding, into a summer of wildfires, is really deserving of a Pulitzer prize for science fiction, if there is such a thing! Gabrielle Canon, I salute you, I thought it was me who thought that the glass was half empty, now I realise I’m not as pessimistic as I once thought. What would CalfireCalfire The California Department of Forestry and Fire Protection (CAL FIRE) is the fire department of the California Natural Resources Agency in the U.S. state of California. It is responsible for fire protection in various areas under state responsibility totaling 31 million acres, as well as the administration of the state's private and public forests. In addition, the department provides varied emergency services in 36 of the state's 58 counties via contracts with local governments. have rather seen? Another dry winter across California, which I suppose in their logic would have meant wildfires would have been much less severe because there was less combustible material to burn.

The Guardian

Downpours bumped California out of the most extreme categories of drought, but the storms also left behind a dangerous mess

Deep underneath the sodden soils and the berms of snow that now coat California, fuels for fire are waiting to sprout. Grasses and other quick-growing vegetation, spurred by the downpours that saturated the state at the start of the year, quickly turn to kindling as the weather warms.
“When that rain comes – and it came last month – that results in significant fuel load increases,” said Isaac Sanchez, a CalFire battalion chief. “[Plants] are going to grow, they are going to die, and then they are going to become flammable fuel as the year grinds on.”
While experts say it’s still too early to predict what’s in store for the months ahead and if weather conditions will align to help infernos ignite, it’s clear the rains that hammered California this winter came as a mixed blessing, delivering badly needed relief while posing new risks. Along with seeding the tinder of tomorrow, the inclement weather hampered efforts to perform essential landscape treatments needed to mitigate the risks of catastrophic fire.
“That is now the reality of the environment in the state that we live in,” Sanchez, added. “We are constantly facing a double-edged sword.”
Reservoirs are more robust than they have been in years. The snowpack, which will slowly release moisture into thirsty landscapes through the spring and summer, is 134% of its average for April, giving the state an important head start. The rains also bumped California out of the most extreme categories of drought, according to the latest analysis from the US Drought Monitor.
But the storms also left behind a dangerous mess.
Strong winds ripped trees from their roots and tore down branches, littering ignition opportunities throughout high-risk areas. Through the slopes and mountainsides, saturated earth crumbled, chewing gaps through roads and highways and hindering access. If these issues linger into the summer and autumn months, they could augment fire dangers.
The deluges also washed out winter plans for prescribed burning – which are often years in the making.
“Those big rains effectively shut down our ability to broadcast burning across the landscape,” said Scott Witt, deputy chief of pre fire planning at CalFire, a division that focuses on mitigation. Adding controlled fire to landscapes is a proven strategy that both creates healthier, more resilient forests and also reduces fuels that can escalate fire severity, but conditions have to be right before they are set.
Landscapes that are too wet won’t burn and high moisture levels can also increase smoke output during a burn, putting the plan at odds with air quality control. Stormy conditions – especially wind – can make them too hard to control.
Other types of treatments, including those that use machines to clear vegetation from overgrown landscapes, were less affected but the storms caused issues with access, Witt said. “We have had areas that have been damaged to the point where roads were washed out, so roadwork needs to be done prior to us bringing resources in,” he said. “The heavy rains do have the potential of limiting or adjusting where we do our treatments.”Data from the agency, published on Friday, shows the number of treatments conducted by the state and its affiliates in December and January is roughly 50% lower than it was the year prior.
There may still be time to amp up the work if conditions are favorable through the spring, and the state was able to do more work than expected during a dry fall. But there is a lot of ground to cover and the state is already playing catch-up after more than a century of fire suppression left forests overgrown and primed to burn.
Now, the climate crisis turned up the dial. Spiking temperatures now pull more moisture out of plants, landscapes and the atmosphere, setting the stage for once-healthy ignitions to turn into infernos. The sisyphean task of treating and retreating the lands is a daunting one, especially now that there’s even more fuel on the ground after the storms – and time is running short.
It takes just days for smaller plants to dry after the rain stops, Witt said, “and dead grasses will start to dry out within an hour or two”. It’s not yet clear whether California will get much more of a dousing before spring. The heavy snowpack could help delay the onset of risks but “if we continue to stay in a dry pattern – even though we had a really strong beginning of winter,” Witt said, “we could easily have an early fire season”.
Noting the urgency, Adrienne Freeman, a spokesperson with the United States Forest Service who is based in California, said the outlook was not as grim as it might appear. There was still a lot that could happen before the onset of high-risk weather.
The cold, rainy conditions also helped forests recover from the drought, which will make them more burn-resistant. Water tables are looking far better and bug species that wreak havoc on vulnerable trees are being better kept at bay. “There is a lot of good news ecologically and we can’t separate that,” she said, noting that the boost may not go as far as it might have in a world without climate change.
“And as far as getting the work done, we just have to remember it is a long-term process,” she added, emphasizing that the effects of landscape treatments must be measured across decades, not years. “It took 150 years to happen, and it is not going to be fixed in a season.”
Acknowledging that the storms affected the agency’s ability to conduct landscape treatments this winter, she said there’s still a lot of work being done. “It doesn’t really have any bearing on what we will be able to do in the spring or how fire season will look in the summer and fall,” she said. “It is way too early for us to anticipate how this is going to affect fire season.”
What will have greater bearing on fire risks this year is the conditions that align come summer and fall – and those are harder to predict.
“There’s a lot left to luck,” said Lenya Quinn-Davidson, director of the Northern California Prescribed Fire Council, echoing Freeman. Last year, when risks were high and the winter was dry, timing fell in California’s favor. Fewer catastrophic fires erupted and, while there were high-severity burns that were deadly and destructive, the acreage scorched by the end of the year was only a fraction of what it was in years past.
This year the conditions are very different. Going into spring with more snow, and wetter soils, different kinds of risks remain. “It speaks to our need to continually think about fire,” Quinn-Davidson said. While the weather will do what it will, more than can be done to prepare for the worst. That includes building on the growing momentum to perform more prescribed burns and other treatments, to champion fire-ready communities, and listen to and learn from Indigenous leaders who performed cultural burns for centuries before white colonizers disrupted essential and natural cycles on the lands.
With harder-to-predict weather patterns, agencies and organizations charged with this work will have to be nimble. “We really need to be ready when the windows present themselves to take advantage of them,” she said, adding that this is where community-based fire management groups – which are sprouting up all over the state – shine.
That’s what gives her hope. Even if some conditions can be left up to chance, there is a lot that can be done. “We have a lot of power and ownership,” she said, noting that landscapes are shaped by people. It will be up to people and communities to ensure the tools are in place to prevent the worst kinds of fires from erupting “We just have to have our hearts in the right place.”

Climate Crisis, Flooding

Infamy, infamy they’ve all got it in for me… Read More »

Winter so far dominated by intense Azores High

Winter 2022-23 [DJFDJF Meteorological Winter comprising the months of December, January & February] has been dominated to a large extent by a more intense Azores high than usual. This has kept things fairly mobile especially the north and has also provided a good deal of dry and quiet weather across southern parts, with increased numbers of overnight frost and fog. Anomalies have been generally between 4 and 8 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar above the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.. The only time the Azores high did relinquish its hold was in December of 2022, when the flow 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. reversed and we saw the only spell of anticyclonic easterlies we’ve seen so far this winter.

Circulation, Pressure, Winter

Winter so far dominated by intense Azores High Read More »

Table of major mid-winter SSWs 1958-2020

The date of the major warming is calculated for each reanalysis product using daily-mean zonal-mean zonal winds at 60N and 10 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar, where the winds must return to westerly for 20 consecutive days between events, and for at least 10 days prior to April 30, following Charlton and Polvani (2007).
The El NiñoEl Niño El 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-Southern Oscillation (ENSOENSO El Niño–Southern Oscillation is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña.) phase (E = El Niño, L = La NiñaLa Niña La Niña is an oceanic and atmospheric phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation climate pattern. The name La Niña originates from Spanish for "the girl", by analogy to El Niño, meaning "the boy". In the past, it was also called an anti-El Niño[1] and El Viejo, meaning "the old man.", N = Neutral) is defined following the convention of the NOAA NCEP Climate Prediction Center, which is based on the DJFDJF Meteorological Winter comprising the months of December, January & February Oceanic Niño Index (ONIONI The Oceanic Niño Index (ONI) is NOAA's primary index for tracking the ocean part of ENSO, the El Niño-Southern Oscillation climate pattern.) using ERSSTv5 data with a +/-0.5C threshold.
The Quasi-Biennial Oscillation (QBOQBO The quasi-biennial oscillation (QBO) is a quasiperiodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found.) phase (E = easterly, W = westerly) is defined using the DJF-mean equatorial QBO time series at 50 hPa from the Freie Universität Berlin.
The frequency of SSWsSSW A sudden stratospheric warming (SSW) is an event in which polar stratospheric temperatures rise by as much as 50 °C in the course of a few days. The warming is preceded by a slowing then reversal of the westerly winds in the stratospheric polar vortex. SSWs occur about six times per decade in the northern hemisphere, and about once every 20-30 years in the southern hemisphere. for each reanalysis is calculated for the 1958-2019 period for 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.-NCARNCAR The US National Center for Atmospheric Research is a US federally funded research and development center (FFRDC) managed by the nonprofit University Corporation for Atmospheric Research (UCAR) and funded by the National Science Foundation (NSF). and JRAJRA The Japan Meteorological Agency (JMA) is an agency of the Ministry of Land, Infrastructure, Transport and Tourism. It is charged with gathering and providing results for the public in Japan that are obtained from data based on daily scientific observation and research into natural phenomena in the fields of meteorology, hydrology, seismology and volcanology, among other related scientific fields. Its headquarters is located in Minato, Tokyo.-55; for the 1958-2002 period for ERAERA ERA stands for 'ECMWF Re-Analysis' and refers to a series of research projects at ECMWF which produced various datasets (ERA-Interim, ERA-40, etcetera).-40; for the 1979-2019 period for ERA-interim; and for the 1980-2019 period for MERRA-2.

Event NameNCEP-NCARERA40ERA-InterimJRA-55MERRA2ENSOQBO 50mb
JAN 195830-Jan-5831-Jan-5830-Jan-58EW
NOV 195830-Nov-58********EE
JAN 196016-Jan-6017-Jan-6017-Jan-60NW
JAN 1963****28-Jan-6330-Jan-63NE
MAR 196523-Mar-65********LW
DEC 19658-Dec-6516-Dec-6518-Dec-65EE
FEB 196624-Feb-6623-Feb-6623-Feb-66EE
JAN 1968****7-Jan-687-Jan-68LW
NOV 196827-Nov-6828-Nov-6829-Nov-68EE
MAR 196913-Mar-6913-Mar-69****EE
JAN 19702-Jan-702-Jan-702-Jan-70EW
JAN 197117-Jan-7118-Jan-7118-Jan-71LE
MAR 197120-Mar-7120-Mar-7120-Mar-71LE
JAN 19732-Feb-7331-Jan-7331-Jan-73EE
JAN 1977****9-Jan-779-Jan-77EE
FEB 197922-Feb-7922-Feb-7922-Feb-7922-Feb-79NW
FEB 198029-Feb-8029-Feb-8029-Feb-8029-Feb-8029-Feb-80EE
FEB 1981************6-Feb-81****NW
MAR 1981****4-Mar-814-Mar-814-Mar-81****NW
DEC 19814-Dec-814-Dec-814-Dec-814-Dec-814-Dec-81NE
FEB 198424-Feb-8424-Feb-8424-Feb-8424-Feb-8424-Feb-84LW
JAN 19852-Jan-851-Jan-851-Jan-851-Jan-851-Jan-85LE
JAN 198723-Jan-8723-Jan-8723-Jan-8723-Jan-8723-Jan-87EW
DEC 19878-Dec-878-Dec-878-Dec-878-Dec-878-Dec-87EW
MAR 198814-Mar-8814-Mar-8814-Mar-8814-Mar-8814-Mar-88EW
FEB 198922-Feb-8921-Feb-8921-Feb-8921-Feb-8921-Feb-89LW
DEC 199815-Dec-9815-Dec-9815-Dec-9815-Dec-9815-Dec-98LE
FEB 199925-Feb-9926-Feb-9926-Feb-9926-Feb-9926-Feb-99LE
MAR 200020-Mar-0020-Mar-0020-Mar-0020-Mar-0020-Mar-00LW
FEB 200111-Feb-0111-Feb-0111-Feb-0111-Feb-0111-Feb-01LW
DEC 20012-Jan-0231-Dec-0130-Dec-0131-Dec-0130-Dec-01NE
FEB 2002****18-Feb-02********17-Feb-02NE
JAN 200318-Jan-0318-Jan-0318-Jan-0318-Jan-03EW
JAN 20047-Jan-045-Jan-045-Jan-045-Jan-04NE
JAN 200621-Jan-0621-Jan-0621-Jan-0621-Jan-06LE
FEB 200724-Feb-0724-Feb-0724-Feb-0724-Feb-07EW
FEB 200822-Feb-0822-Feb-0822-Feb-0822-Feb-08LE
JAN 200924-Jan-0924-Jan-0924-Jan-0924-Jan-09LW
FEB 20109-Feb-109-Feb-109-Feb-109-Feb-10EW
MAR 201024-Mar-1024-Mar-1024-Mar-1024-Mar-10EW
JAN 20137-Jan-136-Jan-137-Jan-136-Jan-13NE
FEB 201812-Feb-1812-Feb-1812-Feb-1812-Feb-18LW
JAN 20192-Jan-192-Jan-192-Jan-192-Jan-19EE
Total Events3729263925
Frequency: Events/Decade6.06.46.36.36.3

I can’t see what the big fuss is about the chances of a change to very cold following an SSWSSW A sudden stratospheric warming (SSW) is an event in which polar stratospheric temperatures rise by as much as 50 °C in the course of a few days. The warming is preceded by a slowing then reversal of the westerly winds in the stratospheric polar vortex. SSWs occur about six times per decade in the northern hemisphere, and about once every 20-30 years in the southern hemisphere. event. More often or not CETCET Central England Temperature in the following weeks is completely unaffected. Here are some examples of SSW events in recent years.

SSW

Table of major mid-winter SSWs 1958-2020 Read More »

Summer 2022 [JJA] Heathrow – Coningsby comparison

I have been collecting hourly 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 many years now from across the world. I must have many tens of millions of observations dating right back to 1973. So I thought it might be interesting to look at some of these hourly observations in more detail.
I have always thought a 24 hour moving average of temperature for somewhere, gives a much better view of the temperature data than just the daily extremes. So the comparison graph between summer 24 hour average temperatures at Heathrow airport and Coningsby for 2022, shows that although Coningsby is now infamous as being the warmest place in 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., with a maximum temperature of 40.3°C, it’s not when you calculate a 24 hour average. Furthermore. analysis of the number of hours above 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 heatwave threshold at Heathrow of 133 hours, far surpasses that at Coningsby of 97 hours, even though the threshold at Heathrow is 28°C and only 27°C at Coningsby. So, not unsurprisingly, I can safely conclude that Heathrow was still the hottest spot in the UK despite what happened on the 19th of July.

Climate, Temperature

Summer 2022 [JJA] Heathrow – Coningsby comparison Read More »

Weatherdiary.uk

Stanmore – November 1970

Welcome to my ramblings and occasional moans about the weather and climate 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. and across the world. I hope you find the blog of interest. I think my tastes in stories about weather and climate are pretty catholic, with a small ‘c’, so there should be something here for anyone with even the vaguest interest in things meteorological. Most of the graphs, maps and tables of weather observations and climate statistics I generate from the many computer programs I’ve written over the years and from free data I daily download from the internet, hopefully these are accurate, but if they’re not please let me know.

If you are viewing this blog on a PC don’t forget to click on the article to expand it.

Weather

Weatherdiary.uk Read More »

Objective Lamb Weather Types 4 Jan – 4 Feb 2023

A drastic change from cyclonic to anticyclonic and in meridionality and cyclonicity from the 20th of January in the objective 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. indices.

LWT

Objective Lamb Weather Types 4 Jan – 4 Feb 2023 Read More »

January 2023 – Global Temperatures

January 2023 in my DIYDIY Do It Yourself global temperature series was the fifth warmest since 1948, and just a shade warmer than January 2022. The 365 day mean temperature continued to flatline last month, being held in check by the ongoing La NinaLa Niña La Niña is an oceanic and atmospheric phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation climate pattern. The name La Niña originates from Spanish for "the girl", by analogy to El Niño, meaning "the boy". In the past, it was also called an anti-El Niño[1] and El Viejo, meaning "the old man." and a cold Antarctic no doubt.

Interestingly the northern extratropics (23.5N to 66.5 N) warmed considerably just after Christmas, daily anomalies ballooned up to 1.2°C for a while before erratically falling back. All connected with the very mild temperatures across North America and that exceptionally warm New Year in Central Europe.

Global Temperatures

January 2023 – Global Temperatures Read More »

January 2023 – Mean Pressure & anomalies

What can you say about January 2023 other than it was another very typical January, mobile and a little on the mild side. The mean pressure chart does completely masks the fact that we had a cold spell in the third week, with a foot of snow here in the Highlands, followed by a very cold anticyclonic spell in the south to follow. The eight charts below of mean pentad pressures do five a little more detail into the subtle variations we’ve seen since Christmas.

Pressure

January 2023 – Mean Pressure & anomalies Read More »

Latest 12 month UK Climate averages

Mean temperatures in 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. in the 12 months to the end of January have fallen back a little and are now just a shade below the 10°C level. Twelve month UK rainfall totals continue to bounce back (98% of the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.), and are now over 1100 mm, up from the lows of below 1000 mm that were seen in last years the dry spell. UK 12 month sunshine totals continue well above the one standard deviation level (111% of the LTA), and above 1500 hours for the fourth consecutive month.

The climate of the UK is considerably warmer, slightly wetter and much sunnier than it was back in 1993.

Climate, Precipitation, Sunshine, Temperature

Latest 12 month UK Climate averages Read More »

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