Llansadwrn (Anglesey) Weather:
Report of the current season.
Snowline histogram 2004-2005
No snow was seen on the mountains. There were some hail showers and possibly sleet. There have been one or two close calls when temperatures on the summits hovered about 1-2C, but I did not see any. The average date of lying snow over the last 5 years is the 31st October. The earliest was on the 17th October 2002 and the latest 17th November 1999. Last year it was on 21st October. Fresh snow fell on the Alps on 15/16th October and in the Highlands of Scotland on the 20th but there has been little, if any, since.
As of the 9th November sadly there has still been no snow to report. Temperatures at the beginning of the month were even warmer, generally 6-7C on the summits during the day. But on the 9th with N'ly airflow it was cooler with temperatures in the afternoon down to 1C. Snow fell in southern Norway, E and N of Bergen, on mountains of up to 8000 ft on the 6th and on the Alps on the 7/8th where up to 45 cm was reported. Further heavy snow brought the the depth up to near a metre in places on the 10th.
With temperatures on the summits hovering around 0.5C on the 10th there was sporadic ice precipitation and a small amount was seen on the N Carnedd Llywelyn and Yr Wyddfa during the afternoon. It was doubtful if it lasted long as temperature rose again by the following morning. But snow fell in the Highlands and Cairngorm during the day on the 11th and reached Snowdonia during the evening. The Snowdon AWS reported a temperature of -1.5C at 1930 GMT during precipitation. On the 12th there was a thin covering of snow around Yr Wyddfa, Crib Goch and the Glyders down to 2500 ft, even a little on the sides of the Llanberis Pass. The Carneddau did rather poorly with just a sprinkle seen on C. Llywelyn. Further snow overnight on 13/14th left thin lying snow Carneddau from Foel-fras to C. Dafydd, and around Snowdon above 2800 ft. With temperatures rising through the day much of this would melted by the 15th. With cold air from the Arctic moving S on the 18th heavy rain turned to snow above 800 ft on the afternoon of the 18th. By 1600 GMT snow was accumulating at 1200 ft and by the morning of the 19th was lying as low as 400 ft with some moderate accumulations on higher ground. Snow showers continued through the day around the summits. On the morning of 20th snow was lying generally around 800 ft but was down to 500 ft in some places. By 09 GMT as showery precipitation moved in off the Irish Sea there was further light snowfall. Temperatures rose during the day but were cold enough to leave a covering around 1500 ft by evening. Temperatures rose during the night, with rain, that thawed most of the snow. On the 21st there was broken cover around 2800 ft in parts and patches seen as low as 800 ft but there was none left on the 22nd. Temperatures on the summits rose to between 7 and 10C. With the return of cold N'ly air on the 27/28th there was a sprinkling of snow seen on the Carneddau (Snowdon obscured) on the morning of the 28th as low as 2800 ft near Ysgolion Duon. Snow showers continued and sprinklings survived on some summits above 3000 ft until the end of the month.
On the morning of the 1st there were sprinklings of snow seen on Carnedd Llewelyn, Crib-y-ddysgl and Yr Wyddfa but these soon melted with rising temperatures. There was no further snow up to the 15th. Colder weather returned on the 16th and there was snow lying on the 17th above 2600 ft across the summits. The 19th was a clear cold day and thin snow was lying generally at 2000 ft but as low as 1500 ft below C. Llywelyn and 1200 ft in Cwm Idwal and the Llanberis Pass. There was ice at 800 ft early in the day. Before dawn on the 20th there were hail and snow showers as low as 300 ft ahead of frontal precipitation. When the cloud cleared at 11 GMT snow was seen generally at 2000 ft but as low as 1200 ft in places but was likely thaw at lower levels through the day. On the 21st snow was lying at 1800 ft, 1600 ft in Cwm Idwal The warmth on the 22nd melted the thin covering. With colder N'ly air there was fresh snow early in the morning of the 24th; at 09 GMT there was lying snow at 2900 ft. On Christmas Day there was slight snow lying at sea level on parts of Anglesey (including Malltraeth). Although this readily melted during the morning accumulations at higher elevations in Snowdonia remained. On Boxing Day snow was lying generally at 1500 ft but was close to the road in the Nant Ffrancon Pass and as low as 700 ft in places. Snow cover remained above about 1500 ft until the 27th. Although there were snow showers early in the day rising temperatures cause a retreat in the snowline to 2800 ft on the 28/29th. By the 30th there were only patches remaining.
The year began poorly for snow with just a few remnant patches on the highest summits. There were some snow showers during the afternoon of the 1st and a little fresh snow was seen on the 2nd on some summits during further showers. There were still a few remnant patches on the 3rd, but there was no fresh snow. One large and several small patches were seen on Crib Goch on the 4th. There was no further snow until the 8th when cold showery air returned for a while bringing wintry showers around the summits during the day. There was no further ice precipitation until late on the 12/13th when there were showers across most of the summits. The amount was small but enough for a sprinkling to remain through the 13th when temperatures kept below freezing on the tops. Further slight showers occurred during the afternoon. With a warmer spell until the 16th no further snow was seen. With a colder NW'ly on the 17th there were frequent showers of icy precipitation from noon onwards. By the end of the afternoon there was slight snow lying above 2800 ft. With more snow overnight by the morning of the 18th there was light snow at 900 ft (600 ft in places) with larger accumulations at higher levels. Showers continued through the morning. There was still a little snow at 2700 ft on the morning of the 19th but return to warmer air soon melted most. Warmer temperatures continued up to the 21st when there was another chance of a return to wintry conditions. Snow fell overnight 21/22nd giving a light covering above 1500 ft down to 1200 ft in places across most summits. There was still snow lying thinly at 1800 ft on the morning of the 24th and was icy in places as low as 500 ft. In sunshine and a strong N'ly wind snow retreated during the afternoon but was still at 2000 ft on the 25th. A little fresh snow had fallen on the summits and there were light accumulations above 2800 ft that lasted until the 26th. Only remnant snow was present on the 27th. With only 8 days of lying snow at 09 GMT it was least since 2002 that had 9 days.
Snow was absent until the 5th when following overnight rain some wet snow was deposited on the summits. Turning colder this snow persisted, and with addition of further snow in showers, good cover was maintained especially on the slopes around C. Llewelyn and C. Dafydd until the 8th. By the 9th as it turned warmer remnant snow patches persisted above 2700 ft and were still there on the 11th. There were frequent showers of ice precipitation as low as 300 ft early on the 13th with snow lying about 2500 ft. On the 14th there was a thin cover as low as 1500 ft on the north-facing slopes. Snow retreated in the sunshine of the 15th leaving remnant snow above 2000 ft on the 16th, but good cover in places above 2500 ft. Fresh snow fell overnight 18/19th leaving slight deposits as low as 850 ft. On the 20th there was light cover above 2000 ft but there was some lying at 1500 ft in places. On the 21st it was icy as low as 500 ft in places; there were sprinklings of snow from 2000 ft and light cover from about 2500 ft. There were some light snow showers during the morning and on the 22nd but they did little to deepen the snow. But by the 23rd, with the freezing level about 1000 ft, more frequent showers had built up light to moderate accumulations in places above that level. It snowed most of the day on the 24th and snow cover gradually built up. On the morning of the 25th there was snow cover above an average height of 450 ft and there were further light falls during the afternoon. On the 26th the snowline was about 1000 ft, but was as low as 600 ft in some places, with cover above 2000 ft moderate in places. With freezing temperatures keeping around 1000 ft, although there was little or no more snowfall, cover was similar on the 27th. With rising temperature and sunshine in the afternoon of the 27th a retreat to 1500 ft occurred, but further precipitation early on the 28th brought the snowline back to 1000 ft. Further moderate snow fell overnight on the 28/1st March with good cover at 1500 ft in most places but as low as 1000 ft in others including Ogwen Cottage near Cwm Idwal.
On the 1st there was slight to moderate cover as low as 1000 ft in central Snowdonia with showers leaving slight deposits through the day even at lower levels. There was little change by the 3rd with good cover maintained above 1200 ft in freezing temperatures. A warm front brought rain overnight 3/4th resulting in the snow cover becoming patchy at lower levels. Later, after the cold front had passed, there was some precipitation of snow over 2000 ft in places. Snow cover remained similar on the northern slopes up to the 6th when hard overnight frost brought icy conditions to most areas. In succeeding days snow became patchier but cover was maintained around most summits. On the 10th there was a little fresh snow overnight and snow showers around the summits during the morning; cover, a little patchy, was above 2500 ft with frequent patches above 2000 ft. There was some showery precipitation on the 11th and more overnight 11/12th with a sprinkling of fresh snow seen in places around 1500 ft on the morning of the 12th. There were further light showers of snow across the summits on the 12th and 13th. There were moderate amounts accumulated on some northern slopes, especially Snowdon covering the railway track to the summit. Frequent snow showers during the afternoon left a sprinkling as low as 1500 ft, but by the morning of the 14th this had disappeared leaving old patches and cover above 2800 ft. With rising temperatures during the following week most of the snow soon melted, but there were remnant patches remaining on the 18th. There were a few very small patches seen on the 28th. The first 15 days saw snow cover and, together with the last 10 days of February, there were 25 consecutive days.
There were wintry showers across the summits on the 4th, 5th and 6th. On the 7th there was light snow as low as 1500 ft in Cwm Idwal and elsewhere some at 2000 ft during the morning. There were further snow showers moving across the summits on the 8th leaving white deposits in their wake as low as 500 ft in parts. On the morning of the 9th the general level of lying snow was 2000 ft but in Cwm Idwal was around 1600 ft. As temperatures rose again snow retreated up the mountain slopes but there was just enough for limited cover over 3100 ft on the 10th mainly on Yr Wyddfa. There were remnant patches on most high summits on the 11th and 12th. Fresh snow fell overnight on 12/13th and was lying above 2700 ft on the morning of the 13th with a good covering between Foel-fras and Carnedd Llewelyn. There was more snow overnight on 14/15th on the summits. On the 16th there were moderate accumulations above 2000 ft and snow was lying as low as 800 ft in central parts, and the Nant Ffrancon Pass. Levels were similar on the morning of the 17th and with heavy overnight precipitation until 14 GMT on the 18th there was moderate (to heavy in a few places) cover above 2600 ft on northern and rounded tops of Drum, Foel-fras and Carnedd Llewelyn in the afternoon. There was cover on Yr Wyddfa summit amounts looked less on the lower slopes. There was little change with cover was at about the same level on the 21st but with temperatures rising amounts thinned and became patchier through the day. On the morning of the 22nd, however, there was still snow on tops and northern slopes of the central Carneddau. There were frequent snow patches remaining on the 26th and some lasted until the end of the month. On the morning of the 27th some ice precipitation was seen on the summit of Yr Wyddfa following showers.
All snow quickly disappeared at the beginning of the month before the weather turned colder again on the 6th when a little ice precipitation was seen early in the day. A deposit of ice precipitation was seen on the summit of Snowdon early on the 9th during showers.
You can view the snowline histograms for previous years here:
You can view complete snowline reports for previous years here:
Report of the current season.
Observations were made as near to 0900 GMT as possible. I have a good view from Llansadwrn, weather permitting, across the Menai Strait towards the Snowdonia Mountains. I can see the northern slopes of the mountain range from Moel Eilio (west of Snowdon), Snowdon summits (Yr Wyddfa and Crib Goch), the Carneddau and to Foel-fras and Drum on the eastern end near the Conwy Valley. With the aid of binoculars I make records of the lowest altitude of snow lying (>50% cover) and any patchy cover (<50%).
These pages are designed and written by Donald Perkins, copyright © 2004 - 2005
Document dated 24 August 2004http://www.llansadwrn-wx.co.uk