Irish Weather Statistics

Artane2002 wrote: »

I'm shocked that I can't remember November 18 2015 if it affected my area like that. I'm not great at remembering Irish weather unless it's something like snow or wind. The earliest weather memories I have of Ireland is Winter 2009-10.

I love November very much, it's my favourite month of the year when we're talking about weather, I actually love cold, sunny, windy and showery days in November. The main reason why I generally prefer November over winter is because November was better than December or January for wintry weather recently, until 2017-18 of course. I've mentioned November 2016 a good few times now... I remember more snow showers that November than December. I still think those days with very low temperatures at the end of the month are memorable and I don't think I'll forget them anytime soon.

November would be my favourite if it weren't for school. :rolleyes:

But hey, it is the month of my birthday after all and of course, my top 2 favourite snow days were in the month, 27th and 28th November 2010.

You really seem to love November 2016.

I didn't get any snow in November 2016 unfortunately, all rain. But that anticyclonic end to the month (as well as some of the days in the first week) that went on for like two weeks with plenty of cold, crisp days was amazing and what an end to a great Autumn continuing into Winter with -5c on December 1st. But sadly, it all ended a few days after. In fact, we went up to 15c on December 7th.

November 2017 was excellent too if you ask me.

nacho libre wants me to do a post on the severe Winters of 1683/84 and 1739/40. You thought 1962-63 was cold? Oh oh, you ain't seen nothing yet. The former especially was a mad Winter and was the coldest Winter of the entire CET series (back to 1659).

Mobhi1 wrote: »

Were the rivers frozen over in Ireland too?

I'm really struggling to find some accounts on Winter 1683-84 for Ireland (been searching all evening) and I've had no luck in doing so I'm afraid. If somebody currently has access to the Irish Newspaper Archive here (since I don't at the moment), perhaps some of them mention that Winter somewhere in any of the issues?

Gordon Manley in his analysis I posted above does mention Dublin for reports on Winter 1683-84:

The Admiralty archives include log-books, which were sometimes kept in ports, from 1669 onward; hence there might well be some reports from Aberdeen or Leith, Liverpool, Plymouth or Dublin for example.

I would think so because they did in 1740 - which I'll discuss about in another post, the second coldest Winter on record. This was then followed by a famine which wiped out some of the Irish population.

Professor Dr. David Dickson did a book on 1740 for Ireland:



If only we had some sort of time machine to go back and see the conditions for ourselves during the season. Although, going by what I've seen here, it would feel like a completely different country.

sryanbruen wrote: »

https://twitter.com/metoffice/status/991690021022281728

This tweet that has been deleted by the UK Met Office now by the way on the May Day maximum temperature record had a typo. It said 1996 but it was meant to say 1999. The record is 23.6c on 3rd May 1999. This is to be beaten by 3-4 degrees tomorrow so completely smashing it out of the park. This Spring we're breaking all sorts of records!

This is every 40mm+ wet day that Valentia Observatory has recorded as far as the Met Éireann historical data goes back to for the station (as it does not go back to when its records began). I raised the criteria 15mm higher than Dublin Airport's post because it's Valentia Observatory, a place that gets these kinds of days quite often unlike Dublin Airport where it's fairly rare. If I didn't raise the criteria higher, the post would be ridiculously long.

If you're on a desktop, you can see the days from wettest to driest out of this list. Simply press on the rainfall total tab of the table and the totals will be put into numerical order, forwards and backwards. Press the tab again for backwards.

Date|Rainfall total (mm)
16 Apr 2018|42.2
4 Oct 2016|51.4
3 Oct 2016|99.9
16 Feb 2016|43.6
11 Sep 2015|55.4
25 Jan 2013|40.6
7 Jan 2013|42.6
18 Nov 2012|41.9
17 Nov 2011|52.3
22 Oct 2011|54.9
7 May 2011|43.6
26 Dec 2010|49.2
12 Jan 2010|58.5
19 Nov 2009|50.4
23 Aug 2009|45.3
14 Jan 2009|41.0
23 Oct 2008|42.0
21 May 2008|40.7
2 Jun 2007|46.9
30 Nov 2006|52.4
25 Oct 2006|55.3
20 Sep 2006|47.0
2 Dec 2005|52.0
25 May 2005|45.8
7 Jan 2005|45.3
11 Mar 2004|42.3
11 Nov 2003|51.3
9 Jun 2003|63.7
13 Apr 2003|52.0
19 Feb 2003|42.3
20 Nov 2002|41.3
31 Dec 2000|40.9
30 Nov 2000|48.5
18 Dec 1999|40.4
8 Sep 1999|54.0
31 Mar 1999|43.1
2 Aug 1998|41.5
16 Oct 1995|42.6
18 Sep 1993|79.9
7 Jan 1992|50.8
30 Oct 1991|42.4
28 Sep 1991|53.2
21 Oct 1988|40.8
18 Jan 1988|45.6
5 Aug 1986|85.6
4 Nov 1985|50.1
28 Feb 1985|43.3
29 Nov 1984|63.5
17 Apr 1984|52.7
15 Dec 1983|52.0
16 Oct 1982|53.9
20 Feb 1982|46.2
17 Sep 1981|55.6
2 Nov 1980|70.5
1 Nov 1980|86.6
4 Sep 1980|43.4
6 Dec 1978|62.0
11 Aug 1978|60.9
15 Oct 1977|64.6
22 Oct 1975|61.5
21 Jun 1970|58.3
12 Nov 1968|44.6
9 Nov 1968|40.8
26 Apr 1968|42.2
6 Aug 1967|42.5
7 Dec 1959|66.5
9 Oct 1959|40.5
31 Mar 1958|40.6
25 Jan 1958|40.9
6 Jul 1957|40.1
22 Jan 1957|40.1
28 Feb 1955|53.6
4 Nov 1952|45.2
14 Nov 1951|43.5
22 Apr 1948|42.4
1 Feb 1947|40.3
8 Jan 1947|45.8
26 Sep 1946|43.5
16 Dec 1944|49.0
19 Oct 1944|46.9


*1 Feb 1947's precipitation was a mix of heavy rain and snow.

1942 is the last year in Valentia Observatory to fail to record a daily rainfall of at least 30mm (I originally had 30mm+ days in the list but it was too long of a post if you ask me).

Data comes from Met Éireann.

Artane2002 wrote: »

Wow... the 3rd of October 2016 was literally 0.1mm short of 100mm!

Yes, that rainfall event in the west was strange to appear in what was otherwise a very anticyclonic month. October 2016 was the driest October since 2007 and in the UK, rainfall average was only 47.4mm which made it the fifth driest on record there. A typical October should be around 105mm.

What happened was that an occlusion front pushed into the west on 3rd October 2016 in against a big block of high pressure setting up over Scandinavia. At the same time, winds were from a southerly direction (before turning easterly later) so bringing up mild air and as warm air can hold more moisture, it just added to the intensity of the rainfall out to the west. Cloone Lake, Co. Kerry had the following daily rainfalls during this period:

2nd October - 68.2mm
3rd October - 198.6mm
4th October - 24.0mm

To compare Ireland's highest daily rainfall total on record, it was 243.5mm at the same station on September 18th 1993.

Event thread here: https://www.boards.ie/vbulletin/showthread.php?t=2057655049



Look what happened a few days after in contrast to this rainfall event (if only this took place in Winter):

The above temperature makes it the warmest early May bank holiday weekend day on record too in the UK.

It's not the warmest May 7th though as that took place in 1976 with a maximum of 29.0c.

https://twitter.com/bbcweather/status/993530300771647489

I was hoping to have a special post for today but I guess not. This will have to do for now.

This is every 30mm+ wet day that Cork Airport has recorded since its records began in 1962.

If you're on a desktop, you can see the days from wettest to driest out of this list. Simply press on the rainfall total tab of the table and the totals will be put into numerical order, forwards and backwards. Press the tab again for backwards.

Date|Rainfall total (mm)
16 Apr 2018|31.0
19 Oct 2017|44.1
27 Sep 2017|30.6
2 Sep 2017|38.6
3 Mar 2017|32.0
14 Oct 2016|31.7
10 Apr 2016|44.1
1 Jan 2016|31.2
30 Dec 2015|30.0
29 Dec 2015|39.6
12 Dec 2015|40.1
5 Dec 2015|31.1
3 Dec 2015|34.4
11 Sep 2015|30.0
25 Aug 2015|33.2
6 Jul 2015|41.3
2 May 2015|38.5
21 Nov 2014|33.1
13 Nov 2014|35.9
15 Oct 2014|31.0
5 Oct 2014|38.6
6 Jun 2014|32.8
16 Jun 2013|38.9
21 Mar 2013|41.2
25 Jan 2013|31.8
28 Jun 2012|33.7
14 Jun 2012|37.5
17 Nov 2011|32.9
2 May 2011|33.8
27 Dec 2010|36.4
31 Oct 2010|31.4
15 Jan 2010|33.5
12 Jan 2010|31.5
30 Dec 2009|39.3
19 Nov 2009|51.2
6 Oct 2009|40.4
11 Jul 2009|36.8
17 Jun 2009|30.6
30 Jan 2009|50.1
14 Oct 2008|32.0
9 Sep 2008|35.5
5 Sep 2008|30.7
29 Jul 2008|31.8
21 Jun 2008|47.7
19 Feb 2007|31.7
2 Dec 2006|32.2
30 Nov 2006|40.2
15 Nov 2006|38.3
25 Oct 2006|42.2
21 Sep 2006|33.7
21 May 2006|30.2
19 Oct 2005|50.1
24 Jul 2005|66.3
21 Mar 2005|34.2
7 Jan 2005|32.9
27 Oct 2004|37.7
26 Jun 2004|33.7
22 Jun 2004|44.3
11 Mar 2004|32.9
9 Jun 2003|39.0
13 Apr 2003|43.0
21 Nov 2002|34.6
20 Oct 2002|33.1
3 Dec 2001|32.7
18 Aug 2001|31.5
14 Aug 2001|52.8
17 Jul 2001|65.5
31 Dec 2000|35.8
5 Nov 2000|43.1
22 Aug 1999|49.6
4 Aug 1999|40.4
29 Dec 1998|35.0
31 Aug 1998|75.8
3 Mar 1998|35.8
17 Nov 1997|47.4
17 Oct 1997|43.0
3 Aug 1997|87.0
5 Aug 1996|37.6
13 Mar 1996|52.8
12 Mar 1996|47.6
6 Jan 1996|37.2
30 Dec 1995|43.7
19 Dec 1995|36.8
24 Oct 1995|33.3
16 Oct 1995|55.8
3 Oct 1995|42.4
9 Mar 1995|36.0
25 Feb 1994|36.3
22 Feb 1994|32.5
19 Feb 1994|37.4
3 Feb 1994|31.5
19 Sep 1993|32.1
7 Sep 1993|42.9
29 May 1993|31.9
29 Mar 1993|35.0
24 Nov 1991|59.3
30 Oct 1991|35.9
28 Sep 1991|46.3
2 Oct 1990|34.2
21 Jun 1990|32.5
16 Dec 1989|51.3
13 Dec 1989|48.4
11 Dec 1989|34.4
30 Aug 1989|33.4
9 Jun 1989|30.7
25 Oct 1988|38.8
21 Oct 1988|56.9
28 Jul 1988|34.1
30 Jun 1988|38.2
28 May 1988|35.2
18 Jan 1988|45.5
12 Jan 1988|34.5
1 Feb 1987|30.7
25 Aug 1986|64.8
5 Aug 1986|56.3
1 Aug 1986|32.1
20 Jun 1985|33.7
20 Jan 1985|32.6
11 Nov 1984|35.4
9 Sep 1983|33.3
17 Jul 1983|33.9
20 Feb 1983|48.2
7 Dec 1982|32.8
4 Dec 1982|30.6
7 Nov 1982|35.7
29 Oct 1982|31.0
16 Oct 1982|37.8
4 Aug 1982|32.2
17 Jun 1982|43.3
20 Feb 1982|41.1
19 Dec 1981|30.8
13 Dec 1981|52.2
30 May 1981|30.5
18 Sep 1980|34.7
26 Dec 1979|34.7
22 Oct 1979|43.7
24 Mar 1979|39.3
10 Feb 1979|36.1
27 Dec 1978|34.1
6 Dec 1978|46.7
25 Jul 1978|31.0
17 Apr 1978|44.9
22 Feb 1978|33.4
3 Dec 1977|34.8
31 Oct 1977|51.2
20 Jan 1977|31.7
17 May 1976|37.6
22 Oct 1975|86.7
10 Jul 1975|83.8 (thunderstorm)
11 Sep 1974|34.5
10 May 1974|32.8
29 Jan 1974|34.6
10 Jan 1974|44.0
4 Jan 1974|45.4
12 Oct 1973|35.5
18 Sep 1973|39.6
3 May 1973|49.3
2 Feb 1972|36.4
14 Jan 1972|35.7
13 Oct 1971|31.1
23 Nov 1970|39.6
17 Jan 1970|33.6
20 Jan 1969|53.6
17 Jan 1969|34.8
9 Jan 1969|55.1
13 Dec 1968|48.1
9 Nov 1968|36.2
19 Sep 1968|41.6
13 Jul 1968|32.4
24 May 1968|34.7
11 Feb 1968|31.4
17 Sep 1967|35.5
5 Oct 1966|32.7
3 Oct 1966|34.3
4 Sep 1966|34.4
9 Apr 1966|31.5
4 Apr 1966|36.6
15 Feb 1966|43.5
25 Jan 1966|42.8
10 Jan 1966|34.1
16 Nov 1965|69.9
17 Sep 1965|51.8
12 Dec 1964|38.3
16 Aug 1964|63.7
21 Feb 1964|46.3
11 Dec 1963|37.0
10 Nov 1963|35.2
30 Oct 1963|56.0
16 Aug 1963|40.6
13 Mar 1963|30.5
29 Sep 1962|31.1


*The only year without a daily rainfall of at least 30mm at Cork Airport was 1992.
*Some of the precipitation on 10 Feb 1979 was snow.

Data comes from Met Éireann.

Introduction

The period February 26 to March 3 2018 was an event that brought widespread heavy snowfalls to the UK and Ireland including a 1 in 30 year snowstorm named Storm Emma as well as very low daytime temperatures breaking records for some in a bitter easterly airstream with air originating all the way from Siberia. These were the snowiest conditions in the countries for the majority since January 1982 whilst the coldest since December 2010. The period was dubbed the 'Beast From The East' by people and the media.

The event was primarily caused by a phenomena called sudden stratospheric warming in the second week of February 2018. There's also some signs that suggest it was caused by the solar cycle being close to solar minimum with solar activity plunging and so many spotless days on the sun. Historically, many of our cold events occur around, at or just after solar minimum.

I will guide you through everything to know about this event within this post or article including impacts, science and statistics.

Sudden stratospheric warming

A sudden stratospheric warming is a phenomena where the stratospheric temperatures rise by a very large amount in a short period of time like a couple of days. In a typical Winter, several minor warming events in the stratosphere tend to occur but sometimes, you can get a major warming event here which does not have a pattern or sequence to foretell us when we can expect one. Major warming events have occurred in multiple consecutive years such as 2006 to 2010 but there have been multiple consecutive years without one too such as 1992 to 1998. The contrasts between orography (the study of the formation of mountains) and land sea temperatures cause long Rossby waves in the troposphere (the layer of the atmosphere where weather takes place). The Rossby waves travel upward to the stratosphere and dissipate here which causes the zonal winds to decelerate and warming of the Arctic occurs.

A major warming event within the stratosphere can either displace, split or obliterate the Polar Vortex. Displacing involves the Polar Vortex going to another location where it would not normally be. Usually, the Polar Vortex lies over the Arctic Circle disallowing cold from filtering down into the mid-latitudes. A split involves the Polar Vortex dividing into two or more vortices with each being in a different location. An obliteration involves the Polar Vortex being non-existent in the stratosphere where the layer is just warm all around with little to no colder than average anomalies being seen.

Canadian Warming events can occur too. These involve the dramatic rises in stratospheric temperature to occur over Canada rather than the Arctic itself. These kind of stratospheric events tend to take place within the period from mid November to early December but as seen from 2018, they can take place outside of this period.

It takes minimum 9-14 days (approximately 2 weeks) for a tropospheric response from the stratospheric warming to take place usually but can take up to 2 months. For example, the February 1981 SSW was followed by a cold end to April with a snowstorm across England or the January/February 1963 SSW made the 1962-63 severely cold Winter more prolonged into February. It's difficult to say when this response occurs exactly and it's also difficult to say when the effects run out of power because the effects can happen multiple times through the Winter and early Spring season such as in March 2013 following the January 2013 SSW when a cold spell took place from March 10th to 13th with a brief milder shot on the 15th into the 16th. However, another cold spell happened afterwards lasting to the 7th April. It is therefore very important we look out for changes in our usual zonal pattern following a SSW event.

With all the explanation of what a sudden stratospheric warming event is behind us, let's talk about the February 2018 SSW event or should I say, events because remarkably, two SSW events took place during the month.

On 9 February 2018, two pools of warmer than average temperatures at 10hPa in the stratosphere appeared with one to the southwest of Greenland and the other to the east of Russia. These combined with one another by the latter part of the 10th causing the Polar Vortex to split with one going over the northwest of Canada and the other to the east of Europe. By the 12th and 13th, temperatures in the stratosphere rose by at least +40c with the pool of warm anomalies to the west of Greenland rising to around -8c which is very warm for the stratosphere. These anomalies gradually cooled down somewhat for a few days before another rise took place over Canada on the 17th February. The temperatures here rose even further than the previous warming event mentioned above rising up to a balmy -4c. The first major warming event was a Polar Vortex split which in of itself was unusual because a split has occurred very few times before, two examples of which were January 1985 and January/February 1991. January 1985 was far similar to 2018's one than 1991 and that was followed by a very cold and snowy spell in the middle of the month two weeks after the event had initially occurred. This gave us an indication that something was down the line for our weather after up to that point what had been overall a rather average Winter temperature wise with some cold and mild fluctuations. The second major warming event was a Canadian Warming which has never occurred in February since stratospheric records began in 1951 so was very unusual to see and there was no historical occurrence to base it on what we could expect following it, it had to be nowcasted. As time got closer, it was revealed that the zonal winds reversed a second time which is likely caused by this Canadian Warming but of course with nature, you'll never get a true answer, we can only theorise. The stratosphere took its time for temperatures to go back to average and in fact, we had to wait 'til mid-March for this to happen at 30hPa so the stratosphere was severely disrupted for a very long time meaning the Spring pattern in the Northern Hemisphere was to have a long delay. Zonal wind speeds had reversed to nearly -40 m/s around mid-February and again for a second time near the end of the month. At this time of year, the zonal wind speeds should be around 20 to 30 m/s so this was of huge abnormality. The below chart showing the mean zonal wind speeds at 10hPa in the stratosphere from June 2017 to May 2018 courtesy of Hannah A. Attard reveals just how extreme the zonal wind reversions were - see the huge downward spikes in February. I'd also like to highlight the downward spike in mid-March on the chart. This was followed by the Son of the Beast from 17-19 March which brought more unseasonably cold conditions and heavy snowfalls, especially on the 18th March. However, the spell was not as severe as the Beast From the East because it was shorter and solar radiation was more intense. Therefore, the snow tended to melt quicker.



Forecasting

Near the beginning to mid February, the UK Met Office had forecasted in their 30 day outlook on the chance of easterly winds to occur during the latter part of the month which would give snow and a plunge in temperatures. They stayed consistent throughout with their outlook on this though towards the third week of February started giving some uncertainty on that low pressure could track close to the north and west giving cloudier and milder conditions here. The reason why they showed the chance of easterly winds in the first place was courtesy of the sudden stratospheric warming event that were to occur on 11-13 February. However with the uncertainty above that they added, it's clear that they underestimated the strength of the zonal wind reversion.

In regards to the sudden stratospheric warming, the GFS model started showing it for the second week of February at the end of January with runs differing on timing and strength. At first, the model showed a Polar Vortex displacement than a split with the vortex being displaced over Canada. I had a look through the archives on seeing a similar evolution historically to what the GFS showed here and the example I could find was from February 1982. February and March 1982 were both largely mild months with little cold incursions. However, the ECM soon started to show warming to occur in the stratosphere too but a major warming causing the Polar Vortex to either split or be obliterated. The two models showing different solutions of the warming caused confusion for a bit before the GFS turned more to the side of the ECM and in fact upgraded the split and warming by the early days of February. The GFS started picking up on a second major warming event to occur following the split about a week after it with the warming occurring over Canada, during the first week of February. This was unusual to see given how Canadian Warmings have never occurred in February since stratospheric records began in 1951. As a result, I was unsure of what to expect but the drop off in zonal wind speeds again in mid-March was a sign. I looked through the archives to find a similar evolution to the split in February 2018 and I came across January 1985 which was strikingly similar.

The models started picking up on a significantly cold easterly to occur from the 26th February onwards in around the second week of February well in Fantasy Island. The models stuck to this theme throughout getting closer to the period but there were plenty of wobbles along the way especially on the ECM model. It is likely that these wobbles were caused by the stratospheric warming events because they were unusual and the models don't contain enough numerical data on such events to really know what's going to happen. However, once the first event was over, we started seeing more universal agreement on the beast to take place before the second event took place and caused a huge mess in the model runs. Some model runs were depicting the high pressure up to the north to stay over Ireland and us to be cut off the easterly. This gave Irish model watchers a horrible taste in their mouth and some bad recollections of the February 2012 easterly. However, what they did not take into consideration was the fact that this had a SSW event, or should I say 2 SSW events causing record breaking reversed zonal winds which early 2012 did not have. There was no major warming event throughout the 2011-12 season yet February 2018 alone had 2. The ICON model which is normally not that popular among people stayed the most consistent on the easterly throughout the runs but even it had a few wobbles likely caused by the SSW events. For what they're usually like and in spite of the wobbles, I think the models did extremely well in forecasting the easterly well in advance with it being shown in Fantasy Island all the way back to early to mid-February.

On the 23rd February, Met Éireann issued a weather advisory on the period for unseasonable cold conditions and snowfalls to take place. Usually, Met Éireann don't jump on the train of hype 'til very close to the time so it was something to see a weather advisory from our own meteorological agency!

Weather Advisory for Ireland

Exceptionally cold weather is forecast for next week with significant wind chill and severe frosts. Disruptive snow showers are expected from Tuesday onwards, particularly in the east and southeast.

Issued:Friday 23 February 2018 12:00
Valid:Friday 23 February 2018 12:07 to Friday 02 March 2018 12:00

On the 26th February, Met Éireann issued an orange status warning.

STATUS ORANGE

Snow-ice Warning for Dublin, Carlow, Kildare, Laois, Louth, Wicklow and Meath

Scattered snow showers later Tuesday and Tuesday night will lead to accumulations of 4 to 6 cm by Wednesday morning. Widespread frost and icy conditions also.
Updates to follow. Please see Weather Advisory.

Issued:Monday 26 February 2018 11:46
Valid:Tuesday 27 February 2018 15:00 to Wednesday 28 February 2018 11:00

On the morning of the 28th February, Met Éireann upgraded the warning in some counties to a red status so schools were automatically closed in the counties in the warning. This was the first red status weather warning in Ireland since ex-hurricane Ophelia of the previous October.

STATUS RED

Snow-ice warning for Dublin, Kildare, Louth, Wicklow and Meath

Heavy overnight snowfall has led to accumulations of snow between 5 and 10cm. Snow showers will continue to occur during today and again tonight with further accumulations. Total snowfall up to midday Thursday may reach 25cm.

Issued:Wednesday 28 February 2018 05:00
Valid:Wednesday 28 February 2018 05:00 to Thursday 01 March 2018 12:00

On the night of 28th February, Met Éireann issued another red status warning but this time for the entire country. An Taoiseach, Leo Varadkar, urged everybody to stay indoors from 4pm on Thursday 1st March 'til 3pm on Friday 2nd March because this was likely the period when Emma was going to wreak havoc the worst on the Emerald Isle. It is also likely he said 4pm as an early time so that people would have time to take action and arrive home. He did this because there was confusion over whether people should work or remain at home following the issuing of Ophelia's red alert in October 2017. However, as he urged people to stay home at an earlier time than when Emma was most likely to impact the country, it just caused more confusion with a lot of people misunderstanding his plans. This warning was to be edited to include just those severely impacted such as Kildare, Dublin, Wicklow and Wexford following 3pm on the Friday and they would continue to update it until Saturday afternoon. Some schools in Kildare and Wexford would continue to be closed on Monday 5th March due to huge disruption from the snow.

Synoptic pattern and summary

Following the major warming events in the stratosphere, the zonal winds dramatically reversed which led to blocking over Greenland and Scandinavia plunging both the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) into very negative territory. We hadn't seen such negative indexes combined to this level since March 2013. The NAO in particular going negative was remarkable given how not a single day so far in Winter 2017-18 had recorded a negative NAO index. The end of November brought negativity of the index but as soon as the month changed so did the index with a positive NAO being recorded on the 1st December 2017. An easterly began to take place on the 22nd February but pressure was high over Ireland with clear air which led to sunny skies and overnight frosts. At this time, low pressure was out in the Atlantic splitting the Polar Jet or jet stream into two with one heading northwards and the other heading southwards. The winds over Ireland were turning to a southerly direction up to the Arctic which led to warm air advection being sent up there and in turn push cold air out into the mid-latitudes including Siberia. As the easterly continued, this cold air in Siberia gradually filtered through Europe getting closer to Ireland all the while. By the afternoon of the 26th, the -10c 850hPa temperatures struck the east of Ireland reaching the west by the afternoon of the 27th. These temperatures at 850hPa continued to drop into the 28th with the -12c isotherm making inroads to the east and even getting down to -14c for a time. In the UK, upper air temperatures were down to -12 to -18c widely with the -20c isotherm not far off. Such temperatures at 850hPa had not be seen in the UK and Ireland since February 1991. This was a definitive Beast From the East alright and something that was very rare with only a certain amount of occurrences in recorded history including February 1956, January 1963, January 1987 and February 1991. Pressure over Greenland and Scandinavia were up to 1061mb and 1056mb respectively with a 974mb low over the Azores. Normally, we have a zonal pattern with an area of high pressure over the Azores called the Azores High and a low pressure over the North Atlantic called the Icelandic Low. However, with the zonal winds completely reversed here, the pattern became the opposite with the low over the Azores and the high up to the north. Like a beast from the east-type event, we very rarely see pressure as high as that over Greenland and Scandinavia as well as pressure as low as that over the Azores. The last time we saw a Greenland high as intense as that was December 2010 (see the chart below). The Scandinavian high was so powerful and intense that it evolved into an anticyclonic storm! It was named Harmut by the Adopt a Vortex program of the Free University of Berlin. A maximum wind gust of 187 km/hr (116 mph) was recorded in Øvre Dividal National Park, Norway close to the centre of the anticyclone. Other hurricane force gusts were recorded across Europe and anticyclonic storms of this intensity are rare events.



As the -10 uppers appeared on the 26th to the east of Ireland, snow grains started to occur which tended to come in intervals through the day. The snow was heavier to the east of the UK by this stage especially to the southeast in the colder air. However, by the 28th, snow showers had become widespread though less confined to the southeast of England as the winds became more of a straight easterly, with the Irish Sea setup to become a snowmaker machine. The first of big blasts of snow for Ireland occurred on the night of the 27th into the early morning of the 28th with gusty easterly winds producing heavy snow showers of 5-10cm and locally even more to the east of Ireland. This resulted in wind chill temperatures widely below -10c in both the UK and Ireland. This was called lake-effect snow because a cold airmass passed over the relatively warm Irish Sea with the conditions being met for streamers to take place. Such conditions include the 850hPa temperatures being at least 13c colder than the sea surface temperature and the long fetch of water (as in there has to be enough distance for the heat of the water to contrast with the cold air and take effect causing the streamers). Further heavy snow showers took place on the 28th across the country continuing into the 1st March before storm Emma started pushing up from the south during the evening. However, some parts did take a while to get a good pasting of snow due to the Anglesey shadow breaking up the fetch. Emma was named by the Portugese Met Service and she was a very complex and unusual storm. Unlike usual winter storms which are formed by a powerful jet stream across the Atlantic, Emma was formed over the Azores courtesy of the Arctic outbreak which in turn was courtesy of the sudden stratospheric warming. The storm brought mild, moist air from the south into the established cold air over top of the country. The storm pushed northwards through the evening of the 1st into the 2nd bringing further heavy snow northwards. As the winds were very gusty coming from an easterly direction, blizzards were widespread with snow drifts up to 7ft. As the snow drifted in the wind, accurate measures of snow depth could not be taken but estimates show that depths would be between 30-60cm widely and even more in very localised spots such as Kildare or Wexford. This made Storm Emma be among the worst blizzards to occur in Ireland along with April 1917, February 1933, February 1947, December 1962 and January 1982.





As the storm pushed northwards and the anticyclonic storm up to the north pushed westwards into North America courtesy of the reversed zonal winds, relatively milder air came along with it melting much of the snow but for some because the snow was so deep, the snow did not fully melt 'til over a week later which given the solar radiation was remarkable. It was good it didn't because flooding didn't become a concern unlike in March 1947 when heavy rain combined with much much milder air from the south produced severe flooding in both countries following the very snowy and cold February which had several snowstorms. However, some freezing rain briefly occurred in England on 2nd/3rd March which gave away to very slippery surfaces and dangerous conditions.





The UK and Ireland on the afternoon of 28th February 2018.



Impacts/stories

For the first time in history on March 2nd 2018, The Late Late Show, which of course is the popular Irish talk show and is the longest running talk show in the world, closed its doors. For safety reasons, their audience and guests couldn't make it so they had to grab random people from the canteen and or off the streets. :pac: The show featured comedian Oliver Callan, Joe Duffy, Deirdre O’Kane and country music singer, Cliona Hagan - not to mention stacks of Brennan’s bread.





Dublin nurses give baby Holly a beautiful gesture in Our Lady's Children Hospital, Crumlin. Holly had been waiting 11 months in the hospital for a heart transplant and did not get to enjoy the snow with her family whilst most did. The nurses didn't want Holly to miss out on her chance of building a snowman. They went outside and filled giant buckets with snow. They put the snow on a tray for Holly to play with.

https://www.herfamily.ie/family/dublin-nurses-beautiful-gesture-during-storm-emma-for-young-girl-in-icu-299808

A woman foolishly decided to swim at Sandycove during Storm Emma. She not only put her only life in great danger by doing so but also the lives of others because they had to save her as the waves overcome her.

https://www.dublinlive.ie/news/dublin-news/woman-swimming-sandycove-during-storm-14362786

A man named Frank Price from Tallaght wore his swimming suit and he jumped out of his two-storey window into his garden which was buried in snow. He said he did it for fun and practicing for the next Winter olympics.

https://www.independent.ie/videos/entertainment/watch-irish-dad-uses-huge-storm-emma-snowfall-to-practice-for-the-next-winter-olympics-36665234.html

86 year old, Eileen Maguire, sled down Sweeney's Hill in Co. Cork with her grandson. This shows you that even old people can have a little fun in the snow!

https://www.irishexaminer.com/breakingnews/ireland/sights-and-sounds-from-day-3-of-the-beast-from-the-east-830532.html

Storm Emma caused approximately 34,000 power outages in Ireland.

http://www.thejournal.ie/storm-emma-power-update-3880853-Mar2018/

I'm not even going to mention the Lidl loot.

Statistics

The beast from the east produced the coldest March conditions for some since March 2013 which had been the coldest March since 1962. However, in terms of the temperatures and snowfalls themselves, it was the most significant spell of winter weather since December 2010. 28th February 2018 was the coldest February 28th for the Central England Temperature (CET) region since 1785 with a daily CET of -3.6c in comparison to 1785's -3.8c. 1st March 2018 was the coldest March 1st in the daily CET series with a daily CET of -3.8c beating 1785's -3.5c. The 28th February was the coldest day in the UK in terms of maximum temperatures since December 1995, even colder than any day in December 2010 (see chart below from the UKMO):



Daily CETs during the Beast From the East

|26 Feb|27 Feb|28 Feb|1 Mar|2 Mar|3 Mar
Daily CET|-0.3|-1.2|-3.6|-3.8|-2.3|0.3


On 28th February, strangely enough, County Cork recorded the lowest of the temperatures with maximums of -1.1 and -1.7c at Cork Airport and Roche's Point respectively, both their lowest since January 1987. The air minimum fell to -5.7c at Gurteen on this day whilst the grass minimum fell to -11.5c at Markree on the 27th.

Colder temperatures were to be recorded mostly on 1st March with Cork Airport getting down to an air minimum of -7.0c, its lowest for March on record. Meanwhile, Tredegar in South Wales recorded a maximum temperature of -4.7c which became the UK's lowest March and Spring maximum temperature on record beating -4.6c at Cassley, Sutherland on March 2nd 2001.

Here's some snow depth graphs for the period in the UK:





Here's a snow depth graph for the period in Ireland, courtesy of Gaoth Laidir:



Data comes from Met Éireann, NCEP reanalysis or the UK Met Office.

In light of today's theme, this post is on the 23 May 2011 low pressure or storm.

A 985hPa area of low pressure passed just to the north of Ireland on the 23rd May 2011 with the lowest pressure recording at an Irish station being 991.2hPa at Malin Head. To no surprise, very strong winds were associated with the low pressure. The highest gust was 78 knots (144 km/hr) at Belmullet and this became the highest May wind gust ever observed in Ireland. Malin Head also broke Irish records with a May mean windspeed of 19.4 knots (36 km/hr) which was the highest mean monthly windspeed for May in Ireland on record just showing how windy and unsettled the month of May 2011 was, not just this 23 May storm alone.

I remember that morning my mother's car needed to be fixed so my cousin had to bring me to school instead and it was lashing. It felt very cool and windy with overcast skies everywhere to be seen. It was not a pleasant morning at all. Fortunately, it brightened up a few hours later.

Claremorris had a daily rainfall of 18.8mm on this day.



Satellite from the University of Dundee on 23 May 2011 showing the storm to the north of the country. It's like a mid-Winter chart for how stormy this was.



This is the event thread on the storm:

https://www.boards.ie/vbulletin/showthread.php?t=2056275472

Data comes from Met Éireann.

Cork Boy 53 wrote: »

Love your work sryanbruen.:) If not done previously could you post some stats for May 1989? I remember that month in 1989 as being very dry and warm following on from a cold March and April that year. Apologies if stats for this month have been previously posted.

I will when I can (perhaps sometime today). Your memories don't fool you it was very dry, very warm and very sunny indeed. It was an excellent month. March however was a mild month but April yes was cold and was one of three significantly colder than average Aprils in the 80s. Oddly enough, said cold Aprils came every three years (1983, 1986, 1989). 1983 and 1989 being excellent Summers too but.... 1986, yeah not good at all haha.

Meanwhile, for yesterday, 11th May, we received two 20mm+ daily rainfall recordings:

Station|Rainfall total (mm)
Cork Airport|21.5
Valentia Observatory|21.9


Data comes from Met Éireann.

Mobhi1 wrote: »

Were the rivers frozen over in Ireland too?

Kieran Hickey states the following in the paper below:

It must be noted that the 1600s is particularly problematic in terms of information survival, due to the cessation of record-keeping with the dissolution of the monasteries, and the upheavals caused by the Williamite and Cromwellian Wars. Therefore the totals for the seventeenth century are unlikely to be truly reflective of what is probably the coldest century of the ‘Little Ice Age’ in Europe.

https://cora.ucc.ie/bitstream/handle/10468/2526/KH_HistoricPV2011.pdf?sequence=4

I generated this graph of Irish stations' maximum temperatures for Summer 1976 today - much like Summer 1975 that I did previously. If you did not know already, 1976 was a hot Summer following another warm to hot Summer in 1975. The combination of two "classic" Summers like 1975/76 is very rare to come by, it's kind of like extremely cold Winters such as 1683/84, 1739/40 and 1962/63. A drought began all the way back in October 1974 and lasted 'til August 1976. This became one of the most severe droughts to hit the UK and Ireland on record with many months in the period coming out drier than average. I will talk more about it in-depth another day, just want to talk about this graph briefly.



Here are some temperature recordings I'd like to note in particular for the moment from the above and another station in Co. Offaly called Boora.

Station|Maximum temperature|Date
Boora|29.4|28 June
Boora|32.5|29 June
Boora|31.4|30 June
Boora|30.1|1 July
Boora|32.0|2 July
Boora|30.5|3 July
Carlow|27.7|28 June
Carlow|31.0|29 June
Carlow|28.8|30 June
Carlow|27.6|1 July
Carlow|29.8|2 July
Carlow|28.0|3 July
Carlow|28.5|4 July
Carlow|27.2|16 August
Carlow|27.0|17 August
Carlow|27.8|25 August
Carlow|29.0|26 August
Kilkenny|27.8|28 June
Kilkenny|31.5|29 June
Kilkenny|28.3|30 June
Kilkenny|27.7|1 July
Kilkenny|30.0|2 July
Kilkenny|27.0|15 August
Kilkenny|27.4|17 August
Kilkenny|27.2|25 August
Kilkenny|28.9|26 August
Valentia Observatory|29.7|1 July
Valentia Observatory|29.1|2 July
Valentia Observatory|27.1|17 August
Valentia Observatory|27.3|19 August
Valentia Observatory|27.2|21 August
Valentia Observatory|27.3|22 August
Valentia Observatory|28.1|26 August


Some facts:

Birr had heatwave conditions (a maximum temperature of at least 25c or above for a period of 5 days+) for a period of 14 consecutive days in August 1976. This is the longest heatwave going by the definition in the Irish records I can find.

The maximum of 32.5c at Boora on 29th June 1976 is the second highest Irish maximum temperature on record and was the highest of the 20th century, the record being 33.3c on 26th June 1887. The same station recorded 32.0c on 2nd July 1976 which at this time came third place for the highest Irish maximum as far as I'm aware (Summers like 1911 or 1955 could have been higher but unsure). The closest we've gotten in recent times to the 1976 and 1887 temperatures is 32.3c at Elphin, Co. Roscommon on 19th July 2006.

Data comes from Met Éireann.

Now that it's been mentioned, I guess I'll do the 1983 post today. Summer 1983 contained the hottest July on record up to that point (beaten in Ireland by 1989, 2006 and 2013 - whilst beaten by 2006 with the CET) and August was very warm too but June was rather average though it did have one warm interlude mid-month as shown by the graph.

1 June 1983 was a very cool day, due to the jet stream being on a very southerly track as shown in the chart. The maximum temperature at Clones was 10.2c. Fortunately, this unseasonably cool day was a one off with temperatures on the up following this day.





June 1983 is not a particularly interesting month. It was rather average temperature wise overall with its averages used back then but nowadays, it's regarded as a cool month and it was also mostly cloudy. Not the most exciting start to a Summer.

The maximum temperature at Birr was 24.9c on the 21st.



As soon as the calendar month changed, temperatures went shooting up above 20c in parts though taking its time to reach those in the north and west. By the latter part of the first week, temperatures reached 25c and were set to rise even higher past the 30c mark on July 12th-15th. The maximum temperature I could find during this spell was 32.2c at Carlow (Oak Park) on July 14th so I correct myself on saying Boora's 32.0c on July 2nd 1976 was the fourth highest temperature on record in Ireland.



Cooler weather took place as the winds reversed to a northwesterly for a brief day or two before temperatures began warming up back into the 20s and reaching more than 25c in a couple of spots again. Severe thunderstorms took place to the south of Ireland on the 17th and 18th as a thundery trough pushed northwestwards from France.



Another northwesterly at the end of the month brought some significant amounts of rain and a drop in temperatures down to the mid teens. You thought that was the end of it all? You thought August was going to be a dire month and this was a sign of what was to come? Wrong! This was not to last long as high pressure again ridged from the Azores in early August. This was the dominant feature for much of the month with another very dry and warm month in store following the dry, warm and sunny July. Maximum accumulated soil moisture deficits had reached about 100mm in most of Ireland by mid-August. Nevertheless, there was a wetter spell from the 15th-23rd with some welcome thundery rain to relieving the drought. August was not as sunny as July with the south being favoured for the sun.



Roche's Point had only 4.2mm in July 1983, 6% of its average July rainfall. Shannon Airport had 12.8mm in July 1983, 18% of its average July rainfall. In contrast, Kilkenny had 150% of its average July rainfall with 94.2mm courtesy of the thunderstorms. Just a few miles away at Mooncoin, Kilkenny had 8.1mm in July 1983.

Data comes from Met Éireann.

This is Trevor Harley's summary for July 1983 in the UK:

The hottest of the century (19.5C), and indeed the hottest month since records began. Also mostly dry and sunny, but with some severe thunderstorms. A ridge of high pressure extended from the Azores as the month started. The temperature reached the magic 32C somewhere in the country every day from the 12-16th, and the average daily maximum at Heathrow in the month was 27.6C. There were 17 consecutive days above 27C (80F) somewhere in the country between the 3rd and 19th, and 22 days above 27C in total; the temperature exceeded 21C somewhere in the country every day but one. The highest temperature of the month was 33.7C at Liphook (Hants.) on the 16th (although this might be a high reading, with 33.0 at Hampton on the 15th and East Bergholt in Suffolk on the 16th being more reliable). A possible record high of 31.2C for Northern Ireland was set at Downpatrick (Co. Down) on the 14th; a more definite 30.8C was recorded at Shaw's Bridge, Co. Down (near Belfast; Belfast Airport saw 28.6C) on the 12th (the equal confirmed highest for the region, with 30 June 1976). The highes temperature recorded in the Isle of Man was set this month with 28.9C on the 12th. Cardiff recorded its highest ever temperature, of 33.1C, on the 13th. Even Coatbridge in Scotland reached 31.5C on the 12rh. It was also very humid. Some cool mist on North Sea coasts with NE winds; but the east coast improved later in the month as winds became more westerly. Thunderstorms on the 6th and 16-17th. Lightning deaths on the 6th; 95 mm of rain at Sevenoaks and 81mm at Croydon. More lightning deaths in the storms of the 16-17th. 68mm of rain in 45 minutes at Cromer. Severe hailstorms. Flooding in the Pennines. A cold front moved south on the 18th, bringing more normal temperatures to the south for a few days before pressure built again. Penzance was flooded in the 22nd. 70mm of rain in one hour in Dumfries and Galloway led to flooding there. It was very warm again at the end, with 32C at Skegness and Liphook on the 29th. More widespread thunder on the 31st. The heatwave almost exactly coincided with the calendar month. This was my summer of love, and I remember being able to sit out in the sun in the parks of Dundee.

Here's some RTÉ Archives videos from July 1983.

https://www.rte.ie/archives/2013/0719/463384-hot-weather-and-water-shortages-1983/
https://www.rte.ie/archives/2013/0709/461484-summer-sunshine-activities-1983/

Here's an article on the Irish myth of long, hot Summers that I happen to agree with a lot, not totally because it says we ONLY remember the good ones. Well, I hear lots of complaints about Summer 1985 all the time and of course, recent dire ones like 2007, 2008 and 2012.

https://www.irishexaminer.com/lifestyle/outdoors/donal-hickey/the-myth-of-long-hot-summers-237480.html

Very brief video on Ireland in Summer 1976. I think this was in one of the RTÉ Archives videos I shared but unsure.

This post is on the late September/early October 2011 "heatwave" in Ireland and the UK (specially for nacho libre since he wanted me to do it, over a month ago so I apologise for the late time coming).

What happened (you could have already guessed) was that an intense high pressure sat to the southeast of the UK with low pressure just out to the west of Ireland drawing in a long fetched southerly to southwesterly airflow. The air was coming all the way from the Canary Islands and Iberia. How this came to fruition was through a warm front that pushed northwards on the 26th September after bringing heavy rain widely on the 25th. This eventually turned to cloud but more rain started to approach from the Atlantic into the west of Ireland and Scotland overnight on the 27th. This brought much cloudier and cooler conditions with temperatures failing to reach 20c. However, the east of Ireland, England and Wales were all under clear air. At this time of year, the sun is still very strong so only made the temperatures shoot up on the 27th, 28th and the 29th before the rain reached the east of Ireland on the 30th and brought some flooding crashing with the warmth which only led to the rainfall intensifying. Oak Park had a daily rainfall of 48.1mm on September 30th.

This period had several of the warmest days of the entirety of 2011. Summer 2011 was very cool and is the coolest Summer of the 21st century so far - the Summer months and January were the only cool months in 2011. Phoenix Park had a maximum of 25.7c on September 28th, its highest for September since 1906 and in fact, this was the station's warmest day of the year, warmer than any day during Summer 2011. Dublin Airport had 24.1c whilst Casement Aerodrome had 24.4c both on the same day, their highest September temperatures since 2003. This combined with abundant sunshine in them places made for some very pleasant weather to be had. I remember going to the beach after school to enjoy it because it was very unusual to see (yeah, I actually made the most of this unlike 2010, I was such a sap!) such warmth in September and especially for how late in the month it was. We didn't have to wait all that long to find such unusual warmth again in September 'cause 2016 did so.

Two new September date records were set for temperature in the UK with maxima of 28.8c on the 29th and 29.2c on the 30th. Two new October date records were set for temperature in the UK with maxima of 29.9c on the 1st and 29.3c on the 2nd with the 3rd being equalled for its highest maxima of all-time of 28.3c (1908 and 1959 were the other years that recorded this on October 3rd). The maxima of 29.9c on 1st October 2011 became the highest October temperature on record in the UK and just 0.1c short of 30c. The previous record was 29.4c on 1st October 1985.



Rainfall was persistent on 1st October 2011 in the east of Ireland leading to further flooding, particularly in the Dublin area with the county having more than half of its October monthly rainfall on this day already (don't forget there was even more severe rainfall to come on the 24th October a few weeks after). Dublin Airport had a daily rainfall of 44.8mm on this day whilst Casement Aerodrome and Phoenix Park had 27.3mm and 35.4mm respectively.







The rain dissipated on the 2nd October generally but still lingering in northern England. More rain but mainly light pushed into the north on the 3rd with warmer temperatures across Ireland but England and Wales bit down on preceding days though still continuing very warm. Ashford, Co. Wicklow had 21.4c on this day. It wasn't very sunny though in the warmth (bar England and Wales), it was mainly cloudy.





MODIS satellite for 1st October 2011.



Data comes from Met Éireann or the UK Met Office.

Some notably warm nights (at least 16.0c as a minimum) that I've come across for Carlow (Oak Park). Keep in mind, this is only one station and its records go from 1967 to early 1997. I had a list of warm nights with the minimum of at least 15.0c but I thought the list was way too long that the criteria needed to be raised. The warmest night of this station (and the warmest I've found so far) was 17.5c on 10th August 1991 - probably a day and month you would never even think of: NCEP reanalysis' for this date below the table.

Date|Minimum temperature
22 Aug 1968|16.4
5 Aug 1975|16.5
3 Jul 1976|16.5
23 Jul 1977|16.2
22 Aug 1978|16.0
17 Jul 1979|16.4
28 Jul 1979|16.6
12 Aug 1979|16.8
4 Sep 1981|16.0
9 Jul 1982|16.0
8 Aug 1982|16.0
11 Jul 1983|16.3
12 Jul 1983|16.1
13 Jul 1983|17.0
14 Jul 1983|17.3
15 Jul 1983|16.8
16 Aug 1983|16.5
18 Aug 1983|16.7
20 Aug 1983|16.2
18 Aug 1984|16.1
24 Aug 1984|16.0
31 Aug 1984|17.2
1 Sep 1984|16.0
29 Jun 1986|16.0
14 Jul 1986|16.0
15 Jul 1986|17.3
16 Aug 1987|16.0
21 Jul 1989|16.0
25 Jul 1989|16.0
3 Aug 1989|16.0
5 Aug 1989|16.0
20 Aug 1989|16.2
30 Aug 1989|16.0
22 Aug 1990|16.0
26 Aug 1990|16.0
10 Aug 1991|17.5
1 Jun 1992|16.6
16 Jul 1992|16.0
31 Jul 1994|16.2
10 Jul 1995|16.8
11 Jul 1995|16.0
19 Jul 1995|17.0
20 Jul 1995|16.2
28 Jul 1995|16.0
29 Jul 1995|16.3
30 Jul 1995|16.2
2 Aug 1995|16.0
3 Aug 1995|16.0
15 Aug 1995|16.8


Data comes from Met Éireann.