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A new sea level pressure record for June in Iceland

The pressure has been observed regularly in Iceland for almost 200 years. Prior to that there are gaps in the record. During the first 20 years there is only one observation per day from one station, but later the observing network became denser and more observations were made per day. From 1920 onwards use has been made of barographs to infer the variation of the pressure between readings.

Sea level pressure above 1035 hPa is not common in Iceland in the month of June and readings above 1040 hPa are exceptional, having occurred only once during the whole time of observations until past Tuesday. This occurred during the late afternoon and evening of 21 June 1939 in Stykkishólmur where 1040.4 hPa were then registered.

Last Tuesday evening the pressure rose to 1040.6 hPa at Reykjavik city airport and to slightly lower values at other stations in the vicinity. The following day the height of the 500 hPa-level over Keflavík was measured as 5870 meters, slightly above the old record height there in June, 5860 m (in June 1988). There is one slightly higher reading at 500 hPa in May 1975 over Keflavík (5880 m).

It is of interest to note that a German team of scientists made upper-air observations in Reykjavík during the spring and summer of 1939. They used a different standard atmosphere for their calculations, but after this has been amended their reading at the time of the 1939 pressure record is higher still at 500 hPa. The value in the c20v2-reanalysis (5960 m) fits well with the (amended) German ascent.

The absolute highest temperatures ever recorded in Iceland were measured during this same episode, 30.5°C at Teigarhorn at the East coast and 30.2°C at Kirkjubćjarklaustur in the SE, on 22 June 1939.

The ongoing episode has not been quite as warm as the one in 1939, the highest temperature value to the time of writing is 25.3°C - an absolute record at the station Skarđsfjöruviti (a lighthouse on the SE-coastal sands) which as been in operation since 1994.


An unusually warm April in Iceland

April 2019 was unusually warm in Iceland. In most of the West and North it was the warmest one on record and the second warmest in the country as a whole. The average temeperature in Reykjavík was 6.5°C, +3.6°C higher than the 1961-1990 mean and +0.2°C higher than the previous record (in April 1974). In Stykkishólmur in the west the average in April was 5.8°C, +4.2°C above the 1961-1990 mean - also a new record. In Akureyri April was also the warmest of all time with an average of 6.9°C, +5.3°C above the 1961-1990 mean. 

The warm weather was "caused" by an unusually persistent spell of Southeasterly winds lasting almeost the whole month (except for the first few days). 

w-blogg020519a

The map shows the average 500 hPa-height in April (ecmwf-analysis - map by Bolli Pálmason) and the very large deviation [colours], positive to the NE of Iceland and negative to the SW. 

On the 30th the temperature in Reykjavík reached a new record maximum for April, 17.1°C, the former record, 15.2°C was old, from April 29 1942. 

Some readers might want to check on links to texts about the situation in Icelandic [google translate might or might not be helpful]: The monthly report of the Icelandic Meteorological Office, Tíđarfar í apríl 2019, and two blogs on "hungurdiskar",  Óvenjulegur apríl í háloftunum [an unusual upper-air April] and Meir af apríl [More on April - a discussion of the circulation and its part in the record].


A new October high pressure record in Iceland

On Saturday night, October 27 2018 a new sea level pressure maximum record was reached in Iceland for the month of October. This new record, 1046.0 hPa exceeded the old one, measured in Akureyri on October 20 1895, by 1,5 hPa (1044.5 hPa). The station at Gjögurflugvöllur, on the east coast of the Northwest Peninsula of Iceland is the site of the new record.

 


A new absolute September maximum temperature record in Iceland

Temperatures above 25°C are rare in Iceland in September and have only been registrered on a few occasions. On 1 September (2017) the maxmimum at Egilsstađir airport reached 26.4°C. This is 0.4°C higher than the previous Icelandic record, measured at Dalatangi on 14 September 1949. The Egilsstađir automatic station has been in place since 1998, but previously, manned synoptic observations had been made on the site or in the nearby village since the late 1940s. The first years of observations there were of dubious quality, but are considered to be reliable from 1955 onwards.

Egilsstađir is a favoured site for high temperatures during summer and have measured higher temperatures than 26°C in June (max. 26.7°C), July (28.8°C) and August (29.2°C). The previous high in September was 22.0°C.

Location of Egilsstađir: 65°16.571'N, 14°24.276'W, 23.5 m above sea level.

On 1 September many stations in the North and East part of the country topped their previous September maxima.

The highest temperature measured in Iceland this summer is 27.7°C, at the station Végeirsstađir in the North on 25 July and was the highest temperature measured in Iceland since 2012.


An unusually low pressure recorded in Iceland

During the night and morning of 30 December 2015 an unusually deep low crossed Iceland. The minimum officially recorded sea level pressure was 930.2 hPa, measured at the station Kirkjubćjarklaustur in the Southeast at 5am. This is the lowest sea level reading in Iceland since 24 December 1989 when the pressure at Stórhöfđi in the islands of Vestmannaeyjar measured 929.5 hPa. On 5 January 1983 the pressure at Stórhöfđi was down to 929.9 hPa. 

During the morning hours the low crossed the country from the south to the north. The map below shows the situation at 9 am.

islandskort-2015-12-30_0900

The lowest reading in the North was at Akureyri at 8 am, 932.0 hPa, the second lowest ever recorded there, exceeded only by the 931.4 hPa measured on 3 January 1933. At that occation the lowest pressure in the country was 923.9 hPa (Vestamannaeyjar). 

The lowest pressure ever recorded in Iceland is 919.7 hPa, measured at Vestmannaeyjar 2 December 1929. However, the reading was made during strong winds, Bf 11. This throws some doubt on the exact value of the pressure, but it was certainly lower than the 1933 reading (when the wind was not a problem). 

There is also a measurement of 929.0 hPa made at Vestmannaeyjar on 27 December 1914. 

There are two (or three) measurements of below 930 hPa pressure in Iceland during the 19th century. Two are considered quite sound, but the exact hPa values can be debated. The third one was made, but later retracted by the observer after an inquiery, however, there are some doubts remaining, because of wind damages that occurred on the same day. 

As seen on the map above the wind was strongest on the eastern side of the low pressure centre. Hurricane force winds (10-min sustained >32.7 m/s) were recorded on 7 stations, the maximum being, 43.9 m/s at the mountainpass Vatnsskarđ in the east, the highest sustained value at a coastal station was 38.6 m/s, at Papey. A gust of 63.8 m/s was recorded at the station Steinar in the south, but has not been ratified at the time of writing.

There was considerable local wind damage in the east, but the main damage was caused by an unusually high sea level inside the eastern fjords where a few seaside houses are probably beond repair. No human injuries were sustained by the weather. 

This was the second great storm to hit Iceland this Deceember. The first one [on 7 and 8 December] was worse in terms of wind and damage, affecting more than 2/3 of the country, blowing cars of roads and destroying houses. Hurricane force winds (sustained) were then measured on 33 stations (compared to 7 now, as mentioned above), the maximum being 50.9 m/s. 


An unusually warm year in Iceland, 2014

The Icelandic Meteorological Office has issued its official statement of the climate in Iceland in 2014 in English. In the Eastern part of the country and in some of the northern areas as well it was the warmest year ever measured and in the rest of the country it was generally the second or third warmest, slightly exceeded by the temperature in 2003 or 1933.

It was the 19th consecutive year of above normal annual temperature in Reykjavík (vis. 1961 to 1990). The annual temperature in Surtsey, 7.2°C is the highest annual mean temperature ever registered at an Icelandic weather station, exceeding the temperature at the same site in 2010 by 0.1°C.

In spite of the high temperatures the weather was changeable and often dull. The first months of the year were especially wet in the North and East and the weather was difficult. In the west it was very dry at the same time with favorable weather conditions. The summer was warm and considered fine in the North and East but in the south it was very wet and dull. The autumn was fine, November extraordinarily warm, but the year ended with an unruly and a rather cold December.

The precipitation in 2014 was above normal at most stations, as was the number of days with precipitation. Snow was light in Reykjavík, as generally in the South and West. Snow covered the ground in Reykjavík for 41 days during 2014, 24 days less than average. The snow was heavy in Akureyri in and covering the ground for 133 days during the whole year 2014, 16 days more than average.

There was less sunshine in Reykjavík and Akureyri than during the recent years, about 100 below the 1961 to 1990 average at both locations and 200 below the average of 2004 to 2013.

The average sea level pressure in Reykjavík was 1001.7 hPa, 4.2 hPa below the average 1961 til 1990. In the long term it is rather low, but the annual pressure in 2011 was lower still.

The wind speed was close to the average for the year as a whole, but December and February were very windy, June was unusually calm. Easterly and Northerly winds were unusually persistent in January and February, westerly and southerly winds were prevalent in September and easterly in November.


An unusually warm November in Iceland

The year 2014 will be one of the warmest ever measured in Iceland. It has a real chance of becoming the warmest of all along the northern and eastern coasts. The odds of a new temperature record is lower in other areas.

November became the fourth month of the year to exhibit an overall anomaly larger than +2 degrees C [the others are: January, June and September]. The table shows the November temperatures and anomalies for selected stations all over Iceland. The month was the warmest ever in Grímsey off the N-coast, measurements have been done there for 140 years. It was also the warmest at Teigarhorn at the Eastern coast, where measurements have been made for 142 years. The station Árnes in the Southern inland also shows its highest November value ever, but as the station has not been located at the same farm throughout the period the rank is slightly more uncertain than at the other stations. The same uncertainty also applies for the rank at the station Bolungarvík at the extreme Northwest tip of the country.

stöđmeananomaly 1961-1990rankof

anomaly

2004-2013

Reykjavík5,54,421443,2
Stykkishólmur4,33,431692,7
Bolungarvík3,72,97 til 81172,8
Grímsey4,33,711402,9
Akureyri3,43,761333,1
Egilsstađir3,94,63602,2
Dalatangi5,73,92763,0
Teigarhorn5,54,111423,3
Höfn í Hornaf.5,83,9   
Stórhöfđi6,23,821382,7
Hveravellir-0,34,52503,1
Árnes4,64,811343,7

 


A remarkably warm June in Iceland

The first six months of 2014 have been very warm in Iceland, overall the second warmest to fifth warmest of all time at stations with long measurement series. At many stations the warm anomalies have culminated in June.

 
In Stykkishólmur in W-Iceland the temperature records go back to 1845. June 2014 ranks as the warmest of the whole period. In Akureyri in the north (records back to 1882) it is the second warmest, exceeded by June 1933 with the closest possible margin, 0.1°C. The average temperature in Reykjavík in June ranks at number four (records back to 1871).


The average temperature at the station Torfur located inland in a valley near Akureyri in the north was 12.7°C. This is equal to the highest monthly average June temperature ever recorded in Iceland. The earlier instance of 12.7°C (Húsavík 1953) has been considered to be dubious because it was 0.4 degrees higher than the second highest June average in the country (Akureyri 12.3, June 1933).

This was also the warmest June ever recorded in Grímsey, an island at the Arctic Circle off the North coast of Iceland. The new record is 0.7°C higher than the earlier maximum and also almost four degrees higher than the 1961 to 1990 June average at the station. This must be considered remarkable at an oceanic site as Grímsey. The sea surface temperatures around Grímsey have also been very high. During the last week of the month the ecmwf sea surface temperature analysis showed an area near Grímsey with an anomaly of +6°C. This area was also very warm last June (2013) and highlights the general anomalous oceanic conditions off the North coast of Iceland prevailing during the last 15 years or so. Even so – this great culmination of warmth is unexpected.

June was generally on the wet side in the Western part of the country, especially in Reykjavík where the month was the second wettest in a series that extends back to 1885 – with a large gap from 1907 to 1919.

 

This was nominally the calmest month of June in the country since 1963 – but the confidence in the homongeneity of the wind speed series low when it comes to a close absolute ranking of mean speeds over a long period.

In spite of this exceptional warm conditions the absolute maximum temperature recorded in Iceland during June 2014 was "only" 23.1°C. But at the same time the temperature in the inhabited areas of the country never dropped below freezing. In the recent record (comparable station network density) this also happened in June 2003 - but before that only in June 1933 (slightly less dense network), June 1909 and 1880. The station density in 1909 and 1880 was much lower than later so these years are not quite comparable to the other three (1933, 2003 and 2014) in this respect.


A January without freezing temperatures

The absolute minimum temperature at Vattarnes in the Eastern Fjords area in Iceland remained above 0.0°C during the whole month of January 2014. This is the first time that this happens at an Icelandic weather station. The final minimum of the month was 0.4 °C (measured at 10 and 14 utc 14 January).

At the nearby island station at Seley (less than 10 km distant) the January minimum was 0.0°C. A few other stations in the country registered their highest January minima ever.

On the whole the temperature variability in Iceland during this month was unusually small. The absolute maximum temperature in the entire country was only 10.1°C, the lowest since 1994 and the lowest minimum in the inhabited areas was -16.4°C, the highest in the books since 1990. The total range (maximum - minimum) was thus only 26.5°C. It was the same in January 1990 but one has to go back to January 1947 to find a lower value. Then the station density was much lower than now and comparison is open to question.

There were very few observations in the highlands until about 1995. In most months the lowest temperature in the country is observed at the highland stations - this time -19,0°C at the Brúarjökull glacier. This is about 6°C higher than the average of the last 10 years.

The absolute temperature range in Reykjavík has only once been as small in January as now (in 1987) and it has by a large margin never been as small in Akureyri (since reliable maximum registrations began there in 1935).

Overall January was warm in Iceland. In the country as a whole it is about the 10th warmest of the period 1874 to 2014, but at some of the stations in the East - both coast and inland it was the second warmest of all time. This was the case at Teigarhorn which has continuous observations back to 1873, only January 1947 was warmer than now.

In Reykjavík it was the 12th warmest (starting in 1871) and 11th warmest in Akureyri (starting in 1882).

The Vattarnes automatic station is located on a low promontory at the mouth of Reyđarfjörđur, the largest fjord in Eastern Iceland:

Vattarnes          64°56.22'N; 13°41.086'W; 5.0 m.a.s.l.  began in 2000 

A synoptic station was in operation there during 1931 to 1943 (no minimum thermometer).

A web search for the name will return some photographs (mainly the lighthouse) and a map search should find the Vattarnes promontory.


A new highland maximum temperature record in Iceland

Iceland was favored by high temperatures during the last part of July. The maximum temperature in the country exceeded 20°C for 14 days in a row. The maximum length of a period with maximum above 20 degrees is 23 days (recorded last year 2012) but warm periods (in this particular sense) of two weeks or more are unusual.

The highest temperature in the country in July was recorded on the 21st, 26,4°C at the station Ásbyrgi in the Jökulsá national park in the northeast.

The headline news of the month, however, was the 25,9°C measured in Veiđivatnahraun in the southern highlands on 24 July. This is the highest temperature ever recorded in Iceland at a station above 400 m a.s.l. The Veiđivatnahraun station is located at the height of 647 m above sea level in a semi-desert area. At the time of observation the relative humidity was extremely low, only 13%.

The station has been in operation since 1993. There were practically no meteorological observations in the highland until the lone all-season manned station was established at Hveravellir in the central highlands in 1965 (640 m a.s.l.). After 1993 an increasingly dense network has been established, mainly at the effort of the Landsvirkjun (national power company).

The earlier maximum temperature registered in the highlands was only exceeded by 0,1°C, 25,8°C , measured at Upptyppingar - in the northeastern highlands.

A table of monthly temperature maximum records in the Icelandic highlands:

 

idyrmondayhrmax °C station name
401920101251712,5 Upptyppingar
401920062211811,1 Upptyppingar
401920003281313,2 Upptyppingar
401920074301718,0 Upptyppingar
401920074301818,0 Upptyppingar
401920005111319,0 Upptyppingar
401920006301424,1 Upptyppingar
665720137241525,9 Veiđivatnahraun
401920048131825,8 Upptyppingar
59702009913919,8 Hallsteinsdalsvarp
597020099131119,8 Hallsteinsdalsvarp
5943200310261317,4 Eyjabakkar
5943199911191016,8 Eyjabakkar
594320101215112,5 Eyjabakkar

All of the station names are googleable.

This is an extract of the icelandic version:

http://trj.blog.is/blog/trj/entry/1307122/

hungurdiskar blog:

http://trj.blog.is/blog/trj/


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Iceland Weather blog

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Trausti Jónsson
Trausti Jónsson
Senior meteorologist at the Icelandic Met. Office. Speciality: Climatology
Okt. 2019
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