BruenSryan

Last year..

Didn't get cooler towards the end of May 2020, in fact it was very warm with sunshine countrywide leading us into a warm first 2 days to June. The breakdown to cooler weather occurred on June 3rd! The northerly really showed its hand by June 5th with thunderstorms for some on the 6th in the east.

It's an easy win for me. I wasn't alive for 1992 but even so statistically, 2020 beats the band by far. May 2020 was Dublin's sunniest month since July 1955 with 295.0 hours. May 1992 sun wasn't anything special with 204.0 hours whilst May 2018 was relatively sunny but not exceptionally so with 224.0 hours and comparable to May 2017 - which out of the two I prefer 2017. The first 10 days of May 2017 (minus the 6th) were great with clear easterly winds giving plenty of sunshine here, low humidity and non-hazy skies whilst I believe southeastern England had to content with cloud a lot. Lockdown rubbish doesn't influence my opinion of how epic May 2020 was. In terms of mean maximum temps, 2020 also beats the other 2. A mean max of 17.3C in 2020 as compared to 16.2C in 1992 and 16.9C in 2018. Oh yeah and to round it off, only 9.3mm of rain in 2020 whilst 2018 had 19.1mm (also very dry) and 1992 had 39.5mm. It's a full house for May 2020 here statistically.

Third place now instead of fourth, behind only 1976 and 1826. In the legacy CET, 1995 was the 3rd warmest.

Some I noticed whilst looking through. Not going to list every one, just some of the more interesting ones. June 1991 11.9C, 0.2 down from 12.1C June 2003 15.9C, 0.2 down from 16.1C July 2003 17.4C, 0.2 down from 17.6C June 2005 15.8C, 0.3 up from 15.5C November 2010 5.1C, 0.1 down from 5.2C April 2011 11.9C, 0.1 up from 11.8C October 2012 9.5C, 0.2 down from 9.7C July 2013 18.5C, 0.2 up from 18.3C July 2014 17.9C, 0.2 up from 17.7C July 2018 19.3C, 0.2 up from 19.1C August 2018 16.8C, 0.2 up from 16.6C October 2019 9.8C, 0.2 down from 10.0C February 2021 5.3C, 0.2 up from 5.1C May 2021 10.3C, 0.2 up from 10.1C August 2021 16.0C, 0.2 up from 15.8C September 2021 16.0C, 0.1 up from 15.9C ------------------------------ Summer 2018 17.4C, 0.1C up from 17.3C. Now warmer than Summer 1995 which has dropped by 0.1C. Essentially swapped figures.

12 May 1945 - 30.6C at Camden Square 27 September 1895 - 30.6C at Stratfield Turgis

Against the 81-10 average, the longest run of consecutive months above average (+0.1C or greater) I know of is September 2006 to June 2007 and 4 of those were over 2C above average too. Don't have anomalies against 61-90 or 91-20 average for every month since 1659 so unsure about those. 91-20 probably similar to 81-10 I'd have thought but to April 2007 instead of June. 61-90 might have been a different period. CET monthly anomalies from 81-10.xlsxCET monthly anomalies from 81-10.xlsx

Final April 2022 CET came out at 9.1C, the 8th consecutive above average month. 1.1C above 61-90 0.6C above 81-10 0.1C above 91-20 Certainly far from the "coolest/coldest April in quite a few years possibly on the way" that was looking incredibly unlikely anyway from the start after April 2021.

I remember reading somewhere saying that the 5-year period of 1971-75 had the lowest precipitation total on record for any 5-year period in England & Wales since records began in 1766. Data is available here. As somebody mentioned above, there was widespread comparisons in the sea surface temperature profiles in the North Atlantic during the summers of 1976 and 2018. It was found that years with similar SSTs to 2018 featured a northward displacement of the jet stream giving increased frequency of the Azores high ridging into the country. There was some correlation with these SSTs and rainfall but results were more mixed with regards to temperature (probably because of warming). The SSTs have been the only reason I know that could have had a play in why high pressure was so extensive in 1976 though this doesn't account for the previous 5 dry years. https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.3628

No memories of it myself as I was too young. For Ireland, the most noteworthy events were: - Record deep low pressure pushed up from the Bay of Biscay on 27/28 October. Valentia Observatory observed a minimum pressure of 957.5 mb. A tidal surge combined with very high tides and southeasterly gales led to severe flooding over southern parts of the country. Cork river levels were the highest seen since 1962. - The widespread white Christmas. Likely the whitest Christmas on record in terms of how many places seen snow falling on the day. However, accumulations weren't significant otherwise. Also a record sunny February and quite a thundery August with numerous thunderstorms giving local floods to me. Not the most interesting year, pretty reflective of the 2000s decade weather wise to be honest which were quite benign.

Feb 1855 is the 5th coldest month on record at the long-standing Phoenix Park station in Dublin. Jan 1881 -0.5C Dec 1878 -0.1C Feb 1895 0.1C Dec 2010 0.1C Feb 1855 0.2C

Think he mentioned it as a quirk rather than being a culmination of what happened in the stratosphere. The only time I've heard the stratosphere possibly impacting the summer is that of 2019 when we got a very dynamic final warming in late April 2019 that was followed by the most negative May NAO index in the record and the summer of 2019, despite being pretty warm and occasionally extremely hot, also featured a notably negative NAO index for all months as well as the longest run of -NAO days for any season. I think there's a good argument to be made there that the dynamic final warming led to the very blocked May and perhaps first half of June 2019 too but after that not so sure due to the non-existence of the SPV at that time of year of course.

The 2021 major SSW occurred in early January with a central date (the day reversal at 60N 10hPa occurred) of 5th January. There was a sudden stratospheric cooling meanwhile through the second week of February when the easterly was going on and it is perfectly normal for this to happen as SPV disruptions cut off wave activity reaching the mid to upper layers of the stratosphere. Depending on when the SSW occurs, radiative cooling due to the time of year (combined with the aforementioned wave activity) also leads to a strong SPV. This is why early SSWE are not necessarily great. If you want to look at previous major SSW events, there's a compendium here. There's also an archive of 60-90N height anomalies here for winters since 1979. It's not only a case of getting the blocking position correct, it's also a case of whether the warming will propagate back downward to impact the troposphere. Karpechko et al (2017) found that 43% of major SSW events are nSSW (non-downward propagating) which is not far from half of the events. Whether a SSW is nSSW or dSSW (downward propagating) is defined by the 1000hPa NAM index.

1990, 1997 and 2020, as Simon mentions in his tweet. Sure you know what each of those springs were like but 1990 very warm with a marked north/south contrast in rainfall (particularly in March). 1997 dry and warm March/April with a very changeable and showery May. 2020 exceptionally sunny and predominantly dry after first half of March.

New Year's Day 1962: -16.1C at Northolt (lowest temp on record in Greater London) 60 years on... New Year's Day 2022: 16.2C at St. James' Park Weather does some strange coincidences sometimes.

Never post in here but bloody hell talk about ridiculousness, 106cm apparently on the ECM 12z in the Irish Midlands... even for a model like this that assumes every flake that falls will settle is something else. Unlikely

Personally I see the late fall of leaves as a good thing as them holding out to late November can give some spectacular displays such as in 2013 when we also had a very delayed spring but it was one of our most colourful autumn colour displays ever. Just need some cool nights to destroy the chlorophyll in the leaves, not very cold though as a severe frost can force a tree to shed all its leaves overnight. Other similarities with 2013 including late warmth in Sep and Oct, sufficient rainfall in Oct and lack of gales.

In terms of my own lifetime, it's easily Nov/Dec 2010 cold spells if anybody knows me. Nothing comes close to the innocence I felt as a kid taking it all for granted and thinking it was normal! The only time there was true Dickensian Christmas scenes around the area probably since 1878 (speaking of 1878..). Going back further, I would either go for Winter 1878-79, January 1881 or Winter 1916-17. 1878-79 had a severe December and January with many many snowfalls that would have been streamer galore for the Irish Sea. Christmas was a bitterly cold white one too before it became milder temporarily after similar to 2010-11. January 1881 had the godfather of all cold spells for Ireland and was the coldest month on record by far in the nation. Many days mid-month well below freezing consecutively day after day with minus mid-double digits including the national record low of -19.1C which stands to this day. It was also very snowy with again tons of streamers like 1878-79 and featured a great snowstorm for southern England too. December 2010 was Dublin's coldest month since January 1881. 1916-17 was a super interesting winter season for Ireland, featured two of our worst snowstorms on record in January and April 1917. December 1916 featured a cold spell too and February 1917 featured frosts of unusual severity with the deep snow from the late January snowstorm still there in places up to mid-February. Then there was the April 1917 snowstorm which is crazy to hear the (limited) stories about how impactful and severe it was. Blacksod at sea level in the northwest had drifts of 8-10 ft after an hour and a half of commencement! Seskin, Co. Waterford had 9 days of snow lying in April 1917 alone. There was also exceptional low temperatures such as -7C at Phoenix Park, Co. Dublin and -15C in Cumbria. Then if things weren't bad enough, once the cold weather left the nation, there was drought conditions going into May which turned out to be much warmer than average; although the summer of 1917 was very poor! An honourable mention also goes out to November 1919 for such an extreme cold and snowy spell for the time of year. -11.1C at Markree Castle on 14th November was the nation's record low for November until 2010. Braemar achieved -23C on the same day, only 2 years in the last 30 have achieved -23C or lower in any month in the UK (Dec 1995 and Feb 2021) yet a November 102 years ago managed it.. there was widespread snow to sea level too. I just find it all so fascinating how this happened in November and it shows the potential of November as a winter month, shame it rarely does fulfill it.

Canadian Warmings have occurred in Nov 1951, Nov 1952, Dec 1954, Nov 1958 (also a major SSW), Dec 1958, Dec 1959, Nov 1962, Dec 1965, Dec 1966, Nov 1968 (also a major SSW), Nov 1972, Nov 1974, Nov 1976, Nov 1977, Dec 1978, Nov 1979, Nov 1980, Dec 1981 (also a major SSW), Nov 1991, Dec 1993, Nov 1996 and Nov 2000. A major warming occurred in early January 1985. There was no observed Canadian Warming according to University of Berlin analysis. North Pole temperatures • Atmospheric Dynamics • Department of Earth Sciences WWW.GEO.FU-BERLIN.DE

No showers here today, lots of sunshine as Dublin loves to get when there's low pressure around! Loving the fresh autumn feel, it was about time.

Wasn't sure where to post this but fun fact... If this September comes out warmer than August for the CET, 2021 will join a very quirky exclusive club of years where April was colder than the preceding March and September warmer than the preceding August in the same calendar year. The only other year since 1659 that has happened was 1750. However, March 1750 was exceptionally mild (8.2C) rather than April being particularly cold (7.7C) relatively speaking.

I calculated more national means and this September as of the 22nd for Ireland is running as the calmest in a record since 1981 with 6.5 kts. 2014 holds the current record with 6.8 kts. Mind the past few days have tended to be windier - 22nd was windiest day since 13 August nationally speaking.

Don't have any wind data for UK but for Ireland, 2021 had been the calmest January to August period since 2010 and that theme has continued into September with the mean average running even closer to 2010 (which was record calm for many stations). Particularly noticed the lack of wind this summer which was reportedly one of the calmest on record:

60 years ago today...

Indeed 93.3 hrs in December 2001. Image below is every month ranked sunniest to dullest for Heathrow as of July 2021. Reservations have to be made for months from September 2005 however as they were recorded with a K-Z sensor instead of C/S recorder.