The author: Dr. Donald Perkins at the weather station but, sometimes, on expedition.

Llansadwrn (Anglesey)

Diary 2017

Logo: Llansadwrn Weather - Melin Llynnon, Ynys Môn

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Times are GMT (UTC, Z). Observations at this station [ ] are 24-h 09-09 GMT, some others { } occasionally refer to other 24-h periods, extremes (first indications) are given in bold and are usually 21-21 GMT. When averages are referred to (.) compares with the last decade and [.] with the new 30-y climatological average [1981 - 2010]. All data are subject to verification and amendment.

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January 2017

The January 1 - the New Year began overcast and dull, but on the mild side with a temperature of 5.1C (dewpoint 3.2C) at 0900 GMT. Visibility was good and a fresh fall of snow was lying thinly at 2500 ft on the Snowdonia Mountains including Cader Idris. A cold front moving S had been over North Wales at midnight and overnight heavy rain had just about ceased leaving a few spots at first in the morning. Pressure was on 1019 mb with Atlantic-high 1045 mb S of Iceland. Britain was in a trough from the Russian Arctic region and there were bands of showers to the N of here. With the cloud soon breaking up the afternoon became sunny [Max 5.7 Min 4.6C Grass 4.0C Rain 0.1 mm]. A bright, but cooler morning on the 2nd with a fresh NNE'ly breeze. Visibility was very good with good views of Llyn and Bardsey Island although it was misty in places around the coast including Rhosneiger. Pressure had risen to 1033 mb now in a ridge from Atlantic-high 1044 mb. Becoming less breezy with scattered clouds becoming less during the morning and the afternoon sunny (Aberporth 6.7h) when the temperature rose to 7.5C (Porthmadog 7.2C) [Max 7.5C Min 1.9C Grass -0.7C Pptn trace]. An overcast morning on the 3rd with cloud hanging over the mountaintops, but visibility was good or very good. The day was brightened by the first appearance of a few snowdrops in the lawn. One day later than last year, but 4 days earlier than the median date. Pressure was steady on 1030 mb with elongated Atlantic- high 1034 mb W of Ireland to the Severn Estuary declining a little. Low 981 mb was over the Norwegian Sea with associated thick cloud over the N of Scotland and North Sea. Little in the way of any sunshine today in the north today [Max 6.8C Min 0.5C Grass -4.0C trace of dew]. A mostly cloudy morning with signs of the cloud breaking up to the north-west. Intermittent slight rain and drizzle at first not amounting to very much volume at all. The dark grey sky gave way to brighter weather in the afternoon turning mostly sunny here encouraging the temperature to rise to 7.5C. Without an air frost so far this winter there have been a few plants with odd flowers about the garden and hedgerows, and the grass is looking very green, but there has been no net increase in dry matter of the standing biomass. Grass has been growing, but has replaced that lost to dieback and decomposition of detritus in December's mild damp conditions [Max 7.4C Min -1.4C Grass -6.5C Rain 0.1 mm]. Clear skies overnight and with Arctic cold air moving S we had the first air frost of the winter -1.4C with -6.5C on the grass. Whiteness was minimal mostly frozen moisture on the grass, little if any on taller vegetation. In frost hollows the air temperature had fallen to at least -5.5C. On the 5th, hardly a cloud in the sky. The sun appeared over the top of the Carneddau at 0858 GMT, a very fine and sunny morning. Pressure was high 1034 mb over North Wales and here rising slowly. Sunny too in the afternoon [Max 7.2C Min -1.4C Grass -6.5C Pptn 0.1 mm].

A complete change on the 6th with overcast sky, rain had started in the last hour and low cloud and mist was moving in from the west. Pressure was on 1031 mb with high 1043 mb over Germany rainfall would be mostly light, and low 965 mb was N of Iceland. There was a large area of light, but patchy, rain moving across Wales. Wet and windy in the afternoon, not worth going outside. [Max 9.7C Min -0.5C Grass -5.0C o/n -1.0C Pptn 7.2 mm]. Thick fog developed overnight, it was thick at midnight on the 7th and was still thick at 0900 GMT. Temperature 9.0C and 100% relative humidity. A very damp morning, trees were dripping moisture like being in a rain forest; and a dull and sunless day [Max 10.0C Min 6.7C Grass 6.0C Pptn 0.7 mm]. Similar on the 8th, very damp indeed ; temperature 8.3C RH 97%, no or little variable direction wind. Pressure was slack over Britain, 1032 mb here rising slowly with a high 1035 mb Atlantic near Brest, France. Sunless again today. [Max 9.5C Min 8.0C Rain 9.2 mm]. And another dull day on the 9th, but pressure 1014 mb was falling quickly with low 969 mb just S of Iceland and a cold front over the Irish Sea. A change in the weather was to be expected and the Met Office had issued what were to be a rapidly changing series of yellow warnings for Anglesey and North Wales of strong 55 mph wind and snow showers later in the week, and perhaps thundersnow that raised several headlines in the popular press - What was thundersnow? A brighter afternoon with a little sunshine; a slight shower later[Max 8.9C Min 7.4C Rain 3.5 mm]. The 10th began fairly brightly, nothing eventful in the night and no snow on the ground on the mountaintops. A pair squirrels were feeding at one of the feeding stations. Cloud was fairly thin and dry at first with some slight rain coming along at times in the afternoon [Max 9.8C Min 4.6C Grass 0.2C Rain 1.1 mm]. A bright morning on the 11th after a slight shower of rain. Pressure was on 1012 mb with lows 966 over the Norwegian sea and 962 mb Greenland Sea. Cold fronts were lying over Wales and SW England. Crepuscular rays were seen shining on the lower slopes of the Carneddau and there were flurries of snow around the summits. The temperature highest 9.8C at 0130 GMT was falling and was 6.6C (dewpoint 3.5C at 0900 GMT. Breezy from the west. Bright afternoon with the temperature continuing to decline reaching 4.4C at 1815 GMT [Max 7.1C Min 6.1C Pptn 1.4 mm]. Snow on lower slopes of the Carneddau.A colder morning on the 12th with some snow pellets falling in the night. Snow pellets on the ground in Llansadwrn.Continuous slight rain here falling as snow on the mountains over about 800 ft with light to accumulations at higher altitudes over 2500 ft. Very dull with thick cloud. Light showers of wet snow pellets here at times afternoon and evening [Max 3.7C Min 2.9C Grass 0.5C Pptn 1.4 mm]. Shower of snow pellets and snow after midnight on the 13th and further falls on the N-facing lower slopes of the Carneddau above 450 ft. Snow cover elsewhere on the mountains was from about 1250 ft. Pressure 1014 mb was rising with lows 979 mb S Norway and 981 mb Netherlands fighting it out against Atlantic- high 1040 mb to the SW, seeming to be winning at the moment. A fair morning, occasionally bright with a moderate to strong N'ly breeze. Heavy snow in the Highlands of Scotland, strong winds over the North Sea and east coast of England with moderate 0.5 m surge tides seen at Cromer and Lowestoft - Met Office warnings had been issued for possible coastal flooding and icy roads inland. Hundreds were evacuated, but in the event the coastal flooding in the following days was not as bad as expected [Max 4.5C Min 0.6C Grass -3.0C Pptn 1.7 mm]. On the 14th with pressure 1022 mb rising with high 1037 mb over sea area FtizRoy while it was low 995 mb E Europe. A sleet shower at 0900 GMT while observing, might not have noticed while indoors. Visibility was moderate, but reduced to poor in the shower. Some snow pellets were still lying on the ground in places and there was melting sleet on the roof of the Stevenson screen. There was snow lying on the mountains at 1250 ft - soon brighter and there were glimpses of sunshine before more rain showers came along in the afternoon; heaviest 1751 GMT [Max 7.6C Min 0.5C Grass -3.3C Pptn 6.2 mm]. There was more light rain in the night and the sky was overcast on the morning of the 15th that began very dull and damp. Moderate misty visibility, 99% RH and it was a little warmer at 6.6C. Warmer air and the temperature rose to 9.8C, Cardiff had the highest 11.9C. Little or no wind and evaporation measures by M. Piche's evaporimeter was zero Some brighter spells in the afternoon, I did see glimpses of sunshine before returning overcast with spells of slight rain and or drizzle. Well it is winter (Loch Glascarnoch 55.2 mm Capel Curig 19.4 mm) [Max 9.8C Min 4.3C Grass 2.6 mm Pptn 0.9 mm].

The first 15-days were on the mild side despite the minor colder intrusion having a mean temperature of 5.5C [(+0.4)] of averages. Rainfall of 33.7 mm below the averages for the month (31%) & [33%].

It was again mild overnight with a minimum of 7.6C on the 16th having some slight rain at times after midnight. Pressure 1029 mb was rising with resident high 1035 mb off Cap Finisterre having a ridge towards the UK. Low 959 mb NE Greenland had a remarkably long associated cloud band extending running over the Norwegian Sea and UK, W France, and the Med to N Africa. Very dull to begin with, cloud base was between 800 and 1000 ft on the mountains this persisting all day. A little lighter before noon and dry, but dull in the afternoon [Max 9.3C Min 7.6C Grass 7.5C Rain 0.3 mm]. The 17th began with the sky obscured in moderate fog and a fine drizzle. There was not a lot of wind and the ground and vegetation remained very wet all day [Max 8.3C Min 4.3C Grass 2.6C Rain 0.9 mm]. Similar day on the 18th, but at least the sky could be seen and it was overcast. A bit misty with moderate to good visibility and spots of rain at 0900 GMT. Pressure was on 1038 mb with a low 991 mb Norwegian Sea and dominating high 1041 Germany surrounded by a horseshoe shaped jetstream. Very dull, damp and sunless [Max 8.5C Min 6.3C Rain 1.5 mm]. Continuing the same weather on the 19th, Anglesey was enveloped in low cloud, it was overcast, dull, very poor visibility and sunless. Small 1.3C temperature range. It was brighter on the other side of the Menai Strait with Llanfairfechan at times in sunshine [Max 7.7C Min 6.4C Rain 0.3 mm]. In complete contrast the sky had cleared at dawn on the 20th and there was just a little cloud to the NE over Liverpool Bay and a few small clouds over the mainland mountaintops. The minimum 4.6C was at 0900 GMT with the barometer steady on 1035 mb in high 1041 mb over SE Europe. A very fine and sunny day with Aberporth reporting 8.0 h of sunshine and Valley 6.6h with a UK highest maximum of 10.0C. A nice twilight with peach and azure blue colours [Max 8.8C Min 4.6C Grass 0.5C Rain nil].

Another sunny day on the 21st after an overnight minimum of 0.5C and a ground frost minimum of -4.9C. The grass had frozen dewdrops with only a slight white frost on the fields earlier. Visibility was very good with some inversion smoke below 1500 ft seen in the eastern end of the Menai Strait. A fine and sunny afternoon, but cloud was seen encroaching in the west before sunset [(Valley 7.6h Bridgefoot 9.1C Porthmadog 8.7C) [Max 7.2C Min 0.5C Grass -4.9C Rain nil]. Well, the fine sunny weather it did not last and on the 22nd it was back to being overcast with poor visibility. Pressure continued to be high on 1024 mb with high 1037 mb SE Europe. There was a low 1005 mb over the Med; low 969 mb was over the Norwegian Sea and 969 mb in the Atlantic S of Greenland. There was some showery precipitation in S Snowdonia and a line of showers over Cardigan Bay to the tip of SW Anglesey. Here, very dull and sunless with a little slight rain in the afternoon [Max 4.5C Min 0.7C Grass -4.1C Pptn trace]. A fine and bright start on the 23rd and the grass minimum had read -2.5C, but there was no white frost seen at 0900 GMT. Pressure was steady on 1027 mb with high 1028 mb stationed over the Channel near Dover. A sunny afternoon although it did turn cloudier later with a fine evening [Max 9.5C Min 1.8C Grass -2.5C Pptn trace]. The 24th began fine, but with moderate visibility. Flights at Heathrow were affected by fog for the second day, with 100 flights reportedly cancelled. Pressure 1024 mb had declined a little with low 980 mb W of Scotland tracking N and high 1029 mb over France. It was windy to the NW where isobars were tightest. Here no trouble with fog, a fine but breezy morning, very windy around noon before moderating, an overcast and sunless day [Max 9.0C Min 4.2C Pptn trace]. A very fine and sunny morning on the 25th with no overnight frost. Pressure was low to the W (965 mb SE Greenland) and high to the E (1033 mb Germany) so there were tight isobars over W UK, but frontal cloud was to the west over Ireland encroaching the over Irish Sea and N of Scotland, sea fog and stratocumulus off the North Sea encroached SE England. There was a little that affected tip of Pembrokeshire and W Anglesey (Valley 1.8h). Otherwise, most of southern Britain, including Llansadwrn and Llanfairfechan was in the clear with Aberporth returning the highest sunshine at 7.9h. The 5.88 MJ m -2 solar radiation was the second highest of the month [Max 9.0C Min 6.0C Pptn nil].

Clear sky overnight and the morning of the 26th was very fine and frosty with a minimum of -1.3C and -6.5C on the grass (equal lowest of the month with the 5th). Calm or sometime light airs from all directions the temperature at 0900 GMT was -0.7C (dewpoint -2.5C) giving us a rare air frost of 3.4h and ice on water. Pressure was 1041 mb with low 987 mb Shannon at 06 GMT. The sun was up so the temperature was soon rising melting the frost on the grass. Visibility was good, but with thick haze. A sunny afternoon and again a clear evening. Solar radiation of 5.97 MJ m -2 was highest of the month [Max 7.2C Min -1.3C Grass -6.5C Pptn nil]. Not as cold overnight as cloud had encroached the minima reflecting the temperatures at 09 GMT yesterday. Today the 27th the temperature was 3.1C (dewpoint -0.1C) and there were 6 oktas of thin cirrus and altocumulus cloud cover. A very fine bright start then turning a little cloudier with some sunny spells in the afternoon. [Max 9.0C Min -0.7C Pptn 5.4 mm]. A different day on the 28th precipitation overnight of 5.4 mm had fallen as snow above 2000 ft on the mountains with lying snow above 2500 ft. At 0900 GMT there was light rain in a temperature of 4.3C, the overnight minimum was 3.1C again taking the temperature of yesterday morning. Rather dull, wet and cooler, but there was a sunny spell in the afternoon. The evening turned showery with a fall of snow pellets at 2340 GMT [Max 6.2C Min 3.1C Pptn 4.3 mm]. A fine morning on the 29th with the sun rising above the Carneddau at 0832 GMT. At 0900 GMT with 6 oktas cloud and a light SE'ly breeze the temperature was 2.3C (dewpoint 1.5C with a 40% chance of ice precipitation). Fresh snow had fallen on the mountains bringing the snowline down to 2250 ft (where lying) with a 30% cover as low as 1250 ft. Turning cloudier, there was some slight rain at times in thickening cloud morning and afternoon [Max 6.3C Min 1.5C Grass -4.1C Pptn 0.6 mm]. With some clear sky overnight there had been a ground frost of -2.0C, but at 0900 GMT on the 30th it had melted and was reading 0.0C. There was heavy moisture on all surfaces including the rain gauges. A bright morning, but a cloudy afternoon with a temperature of 8.5C at 13 GMT. After midnight a Föhn-like wind developed at Gorwel Heights 13.9C was recorded at 0353 GMT, here 12.7C at 0457 GMT and 13.8C AWS at Gorddinog. In similar conditions 16.5C was recorded here in January 1998 on the 10th and 14.6 on the 11th (Bude 12.4C Mona 11.5C) [Max 12.7C Min 1.6C Grass -2.0C Pptn 0.2 mm]. The 31st was a dull old day with poor visibility and light rain falling at 0900 GMT. Nevertheless it was 12.0C at 0900 GMT. At 1240 GMT the temperature at Gorwel Heights rose to 15.1C and Gorddinog AWS 14.5C. These temperatures were not seen here where the maximum was 12.2C. Some brightness around 14 GMT as the cloud thinned and by now the temperature was falling here reaching 8.3C at 1800 GMT and 7.3C just before midnight (Trawsgoed 12.9C Bala 12.6C Rhyl 12.1C) [Max 12.2C Min 9.9C Pptn 1.5 mm].

The month ended with a mean temperature of 5.7C (+0.4) & [0.6] of averages, ranking 13th highest since 1979, but lowest since 2015, It was a another dry winter month with rainfall was 48.0 mm (42%) & [47%] of averages ranking 11 since 1928, least since lowest on record 1997 that had only 6.6 mm.


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February 2017

February 1 - the began brightly after a mild night the air minimum not falling below 7.1C. A very light SSE'ly breeze with a sky of cumulus and cirrus clouds and a contrail. Visibility was good, a little misty, the mountaintops partially obscured. Just a few snow patches were evident on the Carneddau and Snowdon. Pressure 1003 mb was falling slowly with low 984 mb SW of Ireland. Sunny by noon and early afternoon when cloud was encroaching from the west by 1500 GMT. The calm before the storm perhaps, the Met Office had released a yellow warning for strong winds [Max 12.5C Min 7.1C Rain 0.4 mm]. A fine, but dull morning on the 2nd with a light SSE'ly wind. It was again mild, the temperature at 0900 GMT 12.2C (dewpoint 10.1C). Pressure 986 mb was falling rapidly with low 959 mb over the Celtic Sea. The wind strengthened during the day which had some sunny spells. It got very windy in the evening; Capel Curig reported a gust of 78 mph; 64 mph was recorded at Gorwel Heights at 2107 GMT during a spell of 8 hours with gusts in excess of 40 mph (daily mean wind speed 18.8 mph with a wind run of 388.6 miles); and 56 mpg at Gorddinog at 1756 GMT. The highest gust in Llansadwrn was 36 mph at 2314 GMT ( Gogerddan 14.0C Whitechurch 24.6 mm) Gorwel Heights 14.0C [Max 14.3C Min 7.3C Rain 5.3 mm]. The wind moderated overnight and the morning of the 3rd was sunny for a while. Pressure 991 mb was rising while low 981 mb was over the Bay of Biscay at 06 GMT. It was a cooler 6.0C and there was rain, or slight rain and drizzle, from 1230 GMT until 2200 GMT (St James Park 11.8C Scolton CP (Pembrokeshire) 33.8 mm Boulmer (33.8 mm) [Valley 27.6 mm Mona 14.0 mm Capel Curig 9.4 mm] [Max 8.0C Min 4.9C Pptn 6.6 mm]. During the early hours of the 4th a band of precipitation moved onto North Wales, cold enough for ice precipitation here and by first light (about 08 GMT now) there was melting snow pellets and snow at 1000 ft with light to moderate falls at greater altitude on the Carneddau and Snowdon. Moel Eilio and hilltops westward were well covered. Cloud continued to cover southern Britain and NE Scotland. Central areas including here were mostly clear. Cloud developed later in the afternoon and there were further showers over the mountains (Plymouth 10.2C Achnargart 36.6 Aberdaron 15.0 mm Leconfield 8.0h) [Max 8.3C Min 2.2C Grass -2.0C Pptn 0.6C]. A clearing sky in the small hours of the 5th allowed the temperature to fall and freeze moisture on the ground, the grass minimum was heavily coated and had to be scraped off to read -4.2C, soil was not frozen. Air minimum had been 1.0C and currently at 0900 GMT had crept up to 1.9C. The breeze was very light or calm and there were 3 oktas of cloud cover. Good mist visibility with snow cover seen above 2000 ft on the mountains. A dry sometimes sunny afternoon when a pair of goldfinches were regular visitors at the sunflower hearts feeder. Greater spotted woodpeckers favoured the peanut and dripping cake and a red squirrel the peanuts (Killowen 10.8C Magilligan 5.9h Tiree 14.6 mm Valley 4.2 mm and 4.8h sunshine) [Max 6.8C Min 1.3C Grass -4.2C Pptn trace]

A fairly light morning on the 6th with moderately thick ice on the ground and encrusting the grass minimum thermometer that was registering 0.0C, in melting ice, but had been down to -4.3C. There had been heavy dew that had frozen and although the copper rain gauge funnel and bottle was dry the black Davis funnel, on the ground the rim at standard 30 cm height, had a small amount of water in the bottom. I have noticed that the black plastic frequently has condensed moisture on it. On this occasion water in the bottom of the funnel had frozen and prevented the water dropping onto the tipping bucket, the outlet is quite small - smaller than a copper gauge. Not missing the chance to measure the quantity I removed the funnel and allowed the plug of ice to melt in a warm place and collected the condensate. It was 2.5 ml and by calculation this was equivalent to 0.12 mm of rainfall. This amount was little less than the 0.15 mm measured by a dew/frost pad exposed on the ground surface. This 'precipitation' would be recorded by the lysimeter and leads to an under-recording of PE when dew and frost occurs, amounts of 0.2 to 0.3 mm have been recorded and this often results in the TBR recording a tip during the day when the frost plug had melted and it has not rained. Of course this does not happen when the heater is running inside the gauge. The day soon turned duller with rain from 1300 to 1600 GMT. By evening the wind had strengthened and there was more rain. Sunless [Max 9.1C Min 1.1C Grass -4.3C Pptn 3.9 mm]. A brighter morning on the 7th with sunshine at times. Pressure 1011 mb was rising, visibility good and some cumulus clouds were bubbling up over the mountaintops. Snow patches were frequent with large areas of broken snow on the Carneddau. Crepuscular rays were evident in the morning and the afternoon too has a little sunshine at times and some cumulonimbus clouds were spotted in the distance [Max 10.4C Min 3.5C Grass -1.0C Pptn 1.4 mm]. Over night there was a shower of snow pellets finely marking the pad; total precipitation was 1.4 mm and sprinklings of fresh hail and snow gave a lying cover on the mountains above 2750 ft with some as low as 2500 ft. A sunny morning on the 8th, just 2 oktas cloud mainly cirrus and contra. The sun rose at 0814 GMT and the day mostly sunny [Max 8.2C Min 3.0C Grass -1.2C nil Pptn]. Similar on the 9th very fine and sunny, but very cold in the E'ly breeze. There was an extensive white frost on the ground and ice had formed on water. Visibility was only moderate with a moderately thick smoke haze [Max 4.9C Min 0.5C Grass -5.6C nil Pptn]. An overcast morning on the 10th with no precipitation and no frost observed on the grass, any that had formed had disappeared and the grass only slightly damp at 0900 GMT. Air temperature had been down to -0.3C with 2.0 h of frost and on the grass to -3.2C. It was fine with a cold E'ly breeze. Pressure 1028 mb was rising with high 1027 mb over the Atlantic W of Scotland and there was a large high 1050 mb over Scandinavia. Lows were to be found 987 mb off Cap Finisterre and 1000 mb Sicily. Occluded cloud lay over the Channel and there was some rain in SW England. The most significant rain appeared to be in Fair Isle 6.0 mm [Max 4.2C Min -0.3C Grass -3.2C Pptn trace]. Spots of rain with an overcast sky on the morning of the 11th, but slight snow occurring at 1000 ft in Llandegai and around Llyn Ogwen. It had been calm, but a NE'ly breeze had picked up to force 5 [Max 4.9C Min 1.2C Grass 0.5C Pptn 0.5 mm]. Mostly cloudy on the 12th with an ENE'ly wind roaring in the trees resulting in a significant chilling of the 2.6C measured in the screen. Crepuscular rays seen looking towards the mountains that had snow lying above 2250 ft with some as low as 1850 ft with drifting in places. It was sheltered in the garden from the worst of the wind, many goldfinches were visiting the sunflower hearts feeder and a squirrel had also been taking nuts [Max 5.1C Min 2.5C Grass 1.4C Pptn 0.4 mm]. The 13th was a very windy day the E'ly wind of gale force at times. A large beech was blown over in Telford Road in Menai Bridge crushing the bonnet of a car from which the driver escaped closing a main road to the town for several hours. Another tree was brought down out of the shelter belt into the field across the road from the weather station. Apart from the roaring cold wind it was a mostly sunny day [Max 9.9C Min 2.6C nil Pptn]. On the 14th pressure 1019 mb was rising although the day was mostly cloudy with fine broad crepuscular rays visible. The SE'ly wind had moderated force 1; there was inversion haze in the eastern entrance to the Menai Strait and general murky haze resulting in moderate visibility, but mountaintops were in the clear. Here there were many linear snow patches from old drifts as low as 2000 ft and there was enough remaining to record lying snow above 2850 ft. Mostly weak sunshine, a few sunny spells and a slight shower fell in the early evening. Lusa 14.0C Valley 10.1C [Max 10.0C Min 3.0C Grass -1.9C Pptn trace bottle dry, AWS tipped 0.2 mm]. A fine and bright start on the morning of the 15th, visibility was moderate in haze with pressure steady on 1024 mb. Gradually the weak sunshine gave way to sunny spells, briefly cloudier around noon then sunny again in the afternoon. Donna Nook 13.9C Gorwel Heights 13.3C Trawsgoed 12.9C [Max 11.7C Min 3.8C Grass -0.8C Pptn 0.6 mm].

The first 15-days despite 9 days of ground frost were on the mild side for February having a mean temperature of 5.4C (+0.2) & [0.5] of averages. It had been dry with precipitation of 19.3 mm below the averages for the month (27%) & [25%].

The 16th began overcast with good visibility, but after recent rain it was poor to moderate in mist. There were some lighter patches looking towards Conwy. Pressure was steady on 1027 mb with a depression 1010 mb moving eastward just N of Scotland pressure was high generally S Europe and the Med. A wet afternoon with an area of light rain moved across from N Ireland [Max 8.9C Min 5.4C Pptn 2.0 mm]. High pressure over Spain 1030 mb had extended a ridge to the UK and Norwegian Sea on the 17th and pressure here was steady on 1026 mb. It was a cloudy day with good hazy visibility so that only the outlines of the mountaintops could be discerned, it was fine and bright, but with no clear sunshine. The daffodils were well out today on Peacock Hill while species Narcissi in the garden here were looking great. St James's Park 13.8C Braemar -3.0C [Max 10.5C Min 7.6C Pptn 0.2 mm]. Mild again overnight with minima on the 18th in air and on grass 8.3C, what it was at 09 GMT yesterday. Already 9.3C under overcast skies giving the morning a dull and damp feel. It was breezy with a moderate SW'ly so with wind chill it did not exactly feel like what the thermometer indicated. At Gorddinog AWS the temperature at 0007 GMT was 10.9C while at Gorwel Heights it was 11.7C at 0936 GMT this rising to 14.7C at 1240 GMT. At Hawarden the day's maximum was 15.1C. Pressure 1022 mb was rising in a ridge to the N Sea and Baltic, but linear frontal systems stretching N to S over the Irish Sea and UK resulted in a dull morning and mostly cloudy afternoon here although 7.4h sunshine was recorded at Hertsmonceux and 4.5h at Aberporth [Max 11.5C Min & Grass 8.3C Pptn trace]. The 19th began dull with misty poor visibility. There was intermittent drizzle and spots of rain with fog developing in the afternoon. The temperature hovered around 9.3C in the afternoon before rising in the evening reaching 10.3C before midnight [Max 10.5C Min 7.3C Pptn 1.2 mm]. There was low cloud fog on the morning of the 20th at 0900 GMT that lifted only slowly through the morning with the afternoon remaining cloudy. Pressure 1018 mb was falling and continued to fall through the day. Fine and breezy in the afternoon [Max 11.5C Min 7.7C Pptn 0.1 mm].

Another overcast morning on the 21st with the cloud low at 1500 ft on the slopes of the Mountains. Continuing mild with no frost overnight, but it was a rather dull sunless day with slight rain and drizzle most of the day. During the afternoon the SW'ly wind strengthened and the rain heavier during the evening. Hereford 14.7C Cassley (43.2 mm) [Max 10.5C Min 7.8C Pptn 8.7 mm]. The was moderate rain around 04 GMT and little at 09 GMT on the 22nd was dull and damp in low cloud and mist with intermittent drizzle and or slight rain. Pressure was at its highest 1008 mb at 1026 before starting to fall. It was a little drier from 1330 GMT for about an hour before more rain, then light to moderate, came along. As pressure continued to fall the wind strengthened during the evening as Storm Doris making its approach. It was getting lively at 2340 GMT with the wind gusting to 30 mph with the barometer on 997 mb still falling. St James's Park 14.8C Capel Curig (34.2 mm) [46.0 mm] [Max 9.2C Min 7.1C Pptn 18.0 mm]. A very noisy morning on the 23rd as Storm Doris in the vicinity crossing the Irish Sea. Heavy rain and wet snow pellets fell around 0430 GMT with 18.0 mm measures with standing water in the garden and fields. Fallen tree on Gadlys Drive the result of Storm Doris. Pressure bottomed on 981 mb at 0757 GMT with the strong to gale force wind roaring in the tall trees some were noticeably rocking in the wet ground. The observer went out in his hard hat at 0900 GMT with the wind gusting to 50 mph. At Gordinnog there was a gust of 58 mph, 59 mph at Bodorgan, 70 mph at Mona & Rhyl, 81 mph at Caernarfon Airport, Valley & Aberdaron, 83 mph at Lake Vyrnwy with a storm highest gust of 94 mph recorded at Capel Curig. The Britannia Bridge was closed to all vehicles, the closure being enforced by the police, as a result there was gridlock in Menai Bridge where the Suspension Bridge was also closed for a time. Traffic backed up past Llansadwrn on the A5025 and other road including the A55 were similarly at a standstill. A tree fell on a bus shelter on the approach to Pentraeth, fortuneately no one was waiting for a bus. Ferry services at Holyhead were also affected. Several trees and branches were brought down on Anglesey, closing the Pentraeth to Beaumaris road, and the mainland where the Ffestiniog Railway and other venues including Greenwood and the Mountain Zoo at Colwyn Bay were closed. The Cardiff to Chester line was closed by a fallen tree the and Llandudno to Llanwrst line due to fallen trees and landslide. Many power lines were brought down on the island and Menai Bridge was without power with engineers unable to cross from the mainland to effect repairs; they were subsequently escorted across by the police. Some properties were without power on the island for over 48 hours with extra engineers being brought in from Scotland. Here the electricity supply was flashing on and off for about an hour, shutting down the weather station computers, but did not fail. A tree was brought down across the drive at Gadlys closing the road until cleared in the afternoon. [Max 7.2C Min 4.4C Pptn 4.3 mm].

The 24th was respite day with sunshine and light winds. Colder overnight with an air minimum of 1.1C and -3.6C on the grass and there was a fresh slight snowfall on the mountains as low as 2500 ft. Pressure 1017 mb was rising and it was a pleasant afternoon when the sun was shining, just a few honeybees were seen out for a while on white heather in a shelter part of the garden. Scilly Is. 11.0C [Max 9.5C Min 1.1C Grass -3.6C Pptn 9.1 mm]. A wet and windy day on the 25th with leaden overcast skies from the start. Pressure 1006 mb was falling, there had been a gust of 41 mph at 0624 GMT, and the SW'ly was force 6 with light to moderate rain falling at 0900 GMT. Gorwel Heights 42 mph at 1003 GMT. It rained most of the day, watched the rugby match in Edinburgh, Wales lost there first time in a decade - Scotland 29 Wales 13. Electricity was restored today to properties that had been without for over 48 hours. Capel Curig (60.6 mm) [53.0 mm] [Max 9.5C Min 3.5C Pptn 17.0 mm]. Very windy again on the 26th the SW'ly near gale force at 0900 GMT and the sky looking very threatening to the west. Pressure 999.8 mb was falling and gusts of 51 mph recorded at Gorwel Heights at 1502 GMT and 38 mph here at 1545 GMT. Dull, wet and windy all day; Llansadwrn electricity supply failed at 1440 GMT, engineers working on a fault in Llanddona hoped to get it back by 5 pm, but later as there was an additional fault found gave a revised time of 6 pm which was achieved. Missed out on our roast early evening meal. Had a heavy shower 20 mm/h at 1935 GMT Gravesend 14.0C Tyndrum(33.8 mm) Capel Curig (17.4 mm) [34.4 mm] [Max 9.8C Min 6.1C Pptn 7.1 mm]. A colder showery day on the 27th began brightly then turned cloudier before 0900 GMT with showers of rain and ice pellets. Cumulonimbus and thunder were reported by Valley at 0850 GMT. Up to 10 cars were reported to have been in crashes on the A55 between Gwalchmai and Llanfihangel which was for a time closed in both directions, all due to a heavy fall of hail about 08 GMT. With lows 967 mb N of Scotland and 978 mb Newcastle pressure here 985 9 mb was falling rapidly, but poor visibility improved to good and there was weak sunshine later in the morning followed by sunny spells with sunshine in the afternoon The barometer reached a flat bottom of 981.4 mb about 16 GMT. Fresh snow was seen on the mountains lying above 2250 ft and as low as 1250 ft in Cwm Idwal. Further showers of rain and snow pellets in the evening [Max 6.6C Min 0.6C Grass -3.3C Pptn 2.5 mm]. Overnight the air minimum had fallen to 0.6C and -3.3C on the grass and the 28th began with showers of sleet and snow and a temperature of 1.7C at 0900 GMT. Pressure was on 985 mb and the morning continued with frequent showers of sleet. Snow was settling around 1000 ft with fresh snow lying on the mountains above 1500 ft. There was snow too on Cadair Idris. A record breaking amount of 51 cm of snow fell in Reykjavik in Iceland. Despite it name SW parts of Iceland around Reykjavik usually does not get a lot of snow. The record snowfall in the city is 55 cm in January 1937. Murlough 10.4C Dalwhinnie -8.5C Capel Curig (36.6 mm) [Max 6.6C Min 0.6C Grass -3.3C Pptn 8.3 mm].

The month ended with a mean temperature 6.5C, highest since 2013. Rainfall was 97.8 mm, least since 2015, but one of the 26 largest falls since 1928. A dull month with just 49.2 hours of sunshine at Valley the 7th lowest on the Anglesey record since 1931


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March 2017

March 1 - the began brightly with a light WSW'ly breeze after a shower of rain at 08 GMT. At 0900 GMT the temperature was 4.8C and visibility was moderate it being misty. Pressure was steady on 997 mb. Weak sunshine at first in the morning then much sunnier in the afternoon. The evening turned cloud and there was a period of sleet from 20 GMT till just before midnight that fell as snow at higher altitude on the mountains [Max 9.8C Min 1.0C Grass -3.8C Pptn 17.2 mm]. There was further precipitation after midnight and by the morning of the 2nd had accumulated 17.2 mm. It was a misty morning with poor to moderate visibility and at 0900 GMT a temperature of 4.2C. No frost had occurred overnight. It was later fine and sunny before cloud thickened and there was rain from 20 GMT.Dates of flowering of blackthorn in Llansadwrn 1996-2017. The first white flowers of Blackthorn were seen today in Llansadwrn 8 days later than last year, but the second earliest on record here and 19 days earlier than the median date on the 21 March [Max 7.4C Min 3.4C Pptn 0.8 mm]. No frost overnight and the morning of the 3rd was dull and overcast. Pressure 996 mb was falling quickly with low 988 mb over the Celtic Sea with a large mass of cloud over S Britain, W France and Spain. The light SE'ly breeze backed NE'ly during the morning. A sunless day [Max 8.0 Min 4.2C Pptn 1.5 mm]. A much brighter morning on the 4th with some early sunshine. Again no frost with the temperature 7.0C (dewpoint 2.5C) at 0900 GMT. Pressure was steady on 985 mb with an Irish Sea low closeby near Dublin 982 mb steaming N towards the North Channel. We were in a showery airstream and after a fine morning gathering clouds by noon brought a wet afternoon. Craibstone ( 31.2 mm) Capel Curig (11.4 mm) [16.4 mm] [Max 9.4C Min 5.5C Pptn 4.5 mm]. The 5th was a colder day with the temperature 4.6C at 0900 GMT. It had been raining since 0800 GMT and with altitude on the mountains precipitation was of snow above about 1500 ft. There was also snow lying at Llyn Tegid (Bala), which is about 500 ft asl, and the Horseshoe Pass near Llangollen. The temperature on the top of Snowdon was between -5 and -1C. I have a well established rule of thumb, developed over many years, that says if the temperature here is 7C, or below, then there is usually snow on the mountaintops In fact the temperature proceeded to fall and was 3.3C here at 1133 GMT; 2.9C at Gorwel Heights and 3,2C (AWS) at Gorddinog both at 1215 GMT. I saw no ice precipitation seen at the weather station, but there was a good covering on the Carneddau and Snowdon area where the rapid, moderate to heavy fall led to an avalanche risk on some steep slopes. Pressure at 0900 GMT was 983 mb falling with an occluded front moving eastward, associated with Shannon low 978 mb, lying N Wales to Isle of Wight. Later with showery precipitation the temperature recovered in the afternoon rising during the evening to a maximum of 5.2C around midnight. Sunless [Capel Curing 18.2 mm Valley 10.4 mm Rhyl 9.2 mm] [Max 5.2C Min 4.5C Pptn 13.6 mm].


A fine and bright morning on the 6th after a moderate ground frost (-3.5) with frozen dewdrops at the tips of grass leaves and some thin ice on water. Visibility was poor to moderate with mist and weak sunshine that later cleared to give a sunny morning. Pressure 1003 mb was rising quickly in a ridge moving eastward with complex lows 989 mb SW entrance English Channel; 983 mb S of Iceland and 998 mb S North Sea. A record gust of 119 mph was recorded in NW France. The afternoon continued fine before cloud encroached with showers developing during the evening. St James Park 11.6C Scilly Is. (19.4 mm) Valley [8.0 mm] Capel Curing [5.4 mm][Max 9.6C Min 1.8C Grass -3.5C Pptn 6.3 mm].

View of Snowdonia on a grey Anglesey afternoon.

There were showers of rain around midnight then some clear intervals in the early hours of the 7th that allowed the air temperature to fall to 1.7C and -2.5C on the grass. By 0900 GMT the sky was overcast and there was a light S'ly breeze with a temperature of 4.5C. Pressure was high 1032 mb Spain and Iberia while complex low pressure lay over the Atlantic to the west; pressure here 1016 mb in a weak ridge was declining slowly. The morning was fine, damp and cold. The afternoon was dull and grey, but the cloud was moderately high and the snow on the mountains could be seen clearly (above & below right). Clear view of snow on the mountains between C. Llewelyn and Cwm Idwal. The temperature rose to 8.0C by 1600 GMT and further in the evening, with light to moderate rain falling, reaching 9.9C at 0114 GMT next day. [Max 0.9C Min 1.7C Grass -2.5C Pptn 8.4 mm]. A dull and overcast morning and after the rain the ground was very soggy underfoot. Pressure on the 8th was 1010 mb and rising and soon brightening the morning becoming sunny later and in the afternoon. Northholt 15.1C Gorwel Heights 13.1C Cluanie Inn (33.8 mm) [Max 12.3C Min 4.3C Pptn 8.4 mm]. On the 9th pressure 1020 mb was rising rapidly as a ridge approached from the west. A mild 7.7C at 0900 GMT, 5 ocktars cloud, moderate hazy visibility and a W'ly breeze. Fine and sunny; there were a lot of honeybees, and one or two large bumble bees, on the flowers of the heather banks in the garden. Solar radiation was 10.89 MJ m -2, and maximum temperature 13.3C were highest of the month so far. [Max 13.3C Min 6.2C Pptn 0.6C]. The 10th was disappointing under thick grey low clouds giving very poor misty visibility. Later it was bright at times with occasional glimpses of sunshine breaking through as the afternoon became breezier. Chivenor 16.5C Aboyne -2.8C [Max 11.8C Min 5.9C Pptn 1.0 mm].

Backward trajectory analysis of air arriving over Anglesey at 1500 GMT on 11 March 2017. Researched on the NOAA ARL Website.No improvement in the weather on the 11th with overcast skies dominant. Pressure was on 1015 mb with complex low pressure centres in the region of Greenland and Iceland while pressure remained high 1029 mb Azores and Spain. Warm fronts lay over the Irish Sea and it was very dull with solar radiation 1.64 MJ m -2, lowest of the month so far. There was heavy drizzle and light rain from 1500 GMT, heaviest 1700 GMT 1.2 mm per hour, that brought a moderate wet deposition of pink to light reddish-brown Saharan dust (colour when collected and dried MUNSELL® COLOR 5YR 6.5/4). Backward trajectory analyses using the HYSPLIT dispersion model, courtesy of the NOAA ARL Website indicated that parcels of air arriving over Anglesey between 2250 and 2750 m AGL had a Saharan origin (graphic left). The dust could have been picked up in Algeria close to the borders of Morocco and the sparsley populated and disputed territory of Western Sahara before being transported over the Canary Islands, the Atlantic west of Iberia, Bay of Biscay, Celtc Sea, St. George's Channel,, and Cardigan Bay to be washed out by the rain on Anglesey. Hourly trajectories indicated that air was transported from this region for 4 hours until at least 1900 GMT [Max 10.8C Min 8.5C Pptn 2.0 mm].Peacock butterfly on white heather in our Llansadwrn garden. The 13th began overcast and dull with a warm front slow to clear over the Irish Sea associated with low 985 mb over the Norwegian Sea, but pressure 1029 mb was rising and by the end of the morning bright spells developed this leading on to a largely sunny and dry afternoon. Lawn grass maintenance was carried out for the first time this spring [Max 13.3C Min 3.5C Pptn 0.1 mm]. Large fire with pyrocumulus on the Carneddau Mountains. After a dry night the 14th began fine with moderate to good visibility, but the sky was overcast and at 0900 GMT with rain in sight the mountains became obscures and we had spots of rain at 0920 GMT. It was just spots and soon clearing we had a fine warmer sunny afternoon [Max 14.5C Min 7.1C Pptn trace]. With pressure steady on 1033 mb the 15th began brilliantly with just two or three lenticular altocumulus clouds floating with little change in the lee of the Snowdonia Mountains, cloud increased towards noon then dispersed. It was sunny, forecasts had been for a dull days with drizzle, and remained mostly so all day. Beginning with a temperature of 8.4C at 0900 GMT the temperature rose to 14.3C (Gorwel Heights 15.9C) by afternoon and solar radiation to 12.30 MJ m -2, highest of the month so far. There was a large fire with pyrocumulus on the Carneddau Mountains near the Roman Road in the afternoon; there was considerable smoke drift towards Liverpool Bay. I spotted a peacock butterfly in perfect condition on one of the banks of white heather in the garden (photo left) and soon after a comma, both first of the season. Kew Gardens 18.8C Hawarden 17.4C Lake Vyrnwy 11.0 h] [Max 14.3C Min 5.3C Pptn 0.8 mm] . .

The first 15-days had 58.1 mm of rainfall which already was (91%) & [68%] of the monthly total averages. It had also been a little warmer the mean temperature 7.7C was (+1.0) & [+0.7] of averages.

The 16th began overcast and dull but dry at first before a little rain arrived before 0900 GMT. Pressure 1021 mb was falling slowly in a minor trough; the high pressure to the S was 1031 mb N Italy fronts lying to the NW associated with low 978 SE of Iceland. The rest of the morning was fine and became brighter with a little sunshine around noon. The breezier afternoon turned cloudy again and there was some light showery rain from 1515 GMT [Max 11.2C Min 7.3C Pptn 1.2 mm]. Another very poor spring day on the 17th for outdoor activities: overcast with rain in sight at 0900 GMT turning misty as rain started at 0905 GMT and continued most of the morning becoming a little breezy. Pressure 1017 mb was falling in a westerly airflow between low 970 mb Norwegian Sea and high 1027 mb Azores. Affecting us were fronts moving across on a westerly flow associated with low 983 mb Greenland. It turned out to be a miserable day, a little drier early afternoon then more blustery rain as the wind strengthened to near gale force later (Murlough 12.2C Stonyhurst 47.4 mm Capel Curig 29.6 mm Herstmonceaux 6.0h) [Max 9.4C Min 1.9C Pptn 9.1 mm]. Another dull and sunless day on the 18th although pressure 1010 mb was rising between low to the N (983 mb) and high to the S (1032 mb) with the jetstream set up over the UK delivering a series of frontal waves off the Atlantic. With the soil sufficiently saturated there was standing water in small pools around the garden. Did not go out; watched the rugby match on TV from Paris, France 20 Wales 18, with a controversial ending with overtime lasting 20 minutes and disputed substitution of players. (Pershore 16.1C Capel Curig 26.2 mm Lerwick 7.7h Hawarden 1.5h [Max 11.0C Min 9.0C Pptn 6.1 mm]. Continuing the wet weather theme the 19th began wet and windy and continued rain and or drizzle before fog developed later in the afternoon becoming thick before dark. Pressure 1004 mb had been falling and there was little change in the situation with low-pressure in the N (978 mb Iceland) and high-pressure in the S (1029 mb Azores and 1024 mb Spain and the Med) (Eskdalemuir 32.0 mm Capel Curig 20.6 mm) [Max 10.6C Min 9.0C Pptn 6.1 mm].

Continuous rain on the morning of the 20th was light at 0900 GMT and again plenty of standing water around in the garden and roadsides where inadequately drained. Visibility was poor to moderate. Our electricity supply failed at 0740 GMT, coffee prepared, eggs on, but the toast not cooked. Well it could have been worse, supply restored 1107 GMT after a fallen cable on feeder supply had been repaired. The afternoon turned out brighter with sunny spells and a brisk breeze. Later towering cumuli developed with some cumulonimbus over the mountains and there was thunder and lightning and 7 mm hail in Llanfairfechan at 1715 GMT. The thunder was heard here and there were ice pellets to 3 - 5 mm with heavy shower falling at up to 13.8 mm per hour at 1659 GMT. Later further precipitation fell as snow on the mountains (Writtle 14.2C Sennybridge 27.6 mm) [Max 10.5C Min 7.6C Grass 7.6C Pptn 2.2 mm]. A colder morning on the 21st with the air minimum down to 2.1C overnight and a touch of ground frost -1.1C. Bright and breezy the air temperature 4.5C (dewpoint 1.0C) at 0900 GMT. Pressure 1006 mb was rising and we were in a strong showery W'ly air flow with marine closed cell convection packed to the north-west. Snow cover had returned to the mountains with snow lying at 2500 ft on the slopes of the Carneddau. Heavy showers developed in the afternoon with hail, sleet and snow at low levels. There was a heavy sleet shower on the Dinorwic bypass about 1340 GMT and 2-3 minute 8 mm hail in Llansadwrn at 1405 GMT that almost covered the ground. Rain and sleet later in the evening from 2100 GMT till after midnight that fell as snow on the mountaintops of Snowdonia [Max 8.3 Min 2.5C Pptn 5.8 mm]. The morning of the 22nd was overcast with cloud touching the mainland mountaintops at times where there was fresh snowfall. Pressure was 1001 mb near the centre of a low positioned over Cardigan Bay 998 mb at 06 GMT and Severn Estuary 1001 mb at 0900 GMT. there was little or no wind, visibility was very good, temperature 5.7C (dewpoint 4.5C). The morning was brighter at times, although no breaks had appeared here by noon cloud was broken over the Great Orme with a little sunshine in Llandudno. Some heavy showers developed in the afternoon and again in the evening. (Northolt 11.9C Blencartha 40.0 mm Tredegar 23.8 mm Tiree 11.1h) [Max 8.1C Min 2.5C Pptn 7.3 mm]. Another night with some clear sky and bright stars but on the morning of the 23rd it was dull and overcast with mist and fog still lingering in low lying places. Pressure 1019 mb was rising in a ridge from the Azores to N Scotland. A cool 4.9C at 0900 GMT with poor visibility and a heavy dew. A little sunshine in the afternoon with a rather chilly E'ly breeze [Max 11.0C Min 1.5C Grass -1.7C Pptn nil]. A fine and sunny morning on the 24th after a cool night, but frost free with 0.2C on the grass thermometer. With 11.1h of sunshine at Valley solar radiation here was 14.78 MJ m -2, the highest of the year so far. Porthmadog 16.0C [Max 12.2C Min 3.1C Pptn nil].

Dates of arrival of the chiffchaff in the garden in Llansadwrn 1998-2017. Another fine and sunny morning on the 25th and I heard straight away standing at the screen at 0900 GMT that the first chiffchaff had arrived. It was spot on the median date of arrival here, records back to 1998 (graphic left). Singing rather weakly it will take a few days to become stronger; it will be about 3 weeks before the females arrive. It was 9.6C and high-pressure steady on 1034 mb, highest of the month, with little or no wind. It was breezy, however, at the extremities of the high around N Scotland and the English Channel coastal areas. Another largely sunny day with a high solar radiation of 14.97 MJ m -2, highest of the month and the year so far (Aboyne 19.1C Charterhall 12.2h) [Max 15.2C Min 3.4C Grass -2.5C Pptn nil]. Another fine sunny day on the 26th with a sky of wavy cirrus clouds and several contrails to the NE and SW of here. Pressure was steady on 1026 mb, with UK high 1030 mb Tay Estuary, and there was a light NE'ly breeze and clear very good visibility Solar radiation a little less today at 14.48 MJ m -2. (Aviemore 19.9C Kirkwall 12.0h Valley 8.6h) [Max 13.5C Min 5.8C Pptn nil]. The 27th was fine and sunny with a light E'ly breeze backing from SSW'ly. The 3 oktas sky composed of cirrus and altocumulus. Sunny morning and after noon the wind veered S'ly and we caught a Föhn breeze the temperature rising to 17.4C for a while before the wind direction became unfavourable. Solar radiation today was 14.70 MJ m -2. (Aviemore 19.1 Capel Curig 16.9C Rostherne 11.8h Valley 10.8h) [Max 17.4C Min 4.4C Grass 0.7C Pptn nil]. Fine and bright to begin the 28th with a little weak sunshine. Visibility was moderate to poor with thick haze enhanced by Saharan dust. Pressure had fallen and was steady on 1016 mb with a disturbance over the Celtic Sea. Pressure was high 1029 mb Gibraltar Strait and the Adriatic and low 967 mb S Greenland. A fairly cloudy day apart from a glimpse of sunshine around noon; showery rain before midnight (Gravesend 19.1C Rhyl 15.5C St Athan 9.0 mm) [Max 14.8C Min 6.7C Pptn 6.2 mm]. A spell of rain after midnight mostly light heaviest around 05 GMT on the 29th with sky overcast at dawn with drizzle at 0900 GMT. A dull and misty morning with light rain and or drizzle through the day that was sunless (Cranwell 17.8C Rhyl 14.8C Whitechurch Pembs. 30.4 mm [Capel Curig wettest in Europe today 33.4 mm] [Max 12.6C Min 8.6C Pptn 5.3 mm]. Another very wet, but mild, day on the 30th. There was a little standing water at 0900 GMT and a temperature of 12.2C. Pressure was on 1012 mb and there was a cold front over the Irish Sea and low 983 mb W of Ireland. Pressure was high 1031 mb over the Adriatic and 1029 mb N Africa. Continued wet and windy with low ragged cloud on a moderate S'ly wind. Heavy pulses of rain from 1800 GMT (49 mm/h) petering out by 2200 GMT. The rainfall for the day 19.2 mm gave the wettest day of the month (Gravesend 22.1C Capel Curig 46.0 mm Herstmonceux 9.8h) [Max 12.2C Min 11.3C Pptn 19.2 mm]. There were a few patches of blue sky appearing at 0900 GMT on the 31st as pressure 1006 mb was rising. There was a blustery force 5 SSW'ly wind and a clearer slot developed with a little sunshine at times (Hull E Park 18.9C Hawarden 16.4C Harris Quidnish 32.8 mm Mumbles Hd. 17.4 mm Sheffield 6.3h) [Max 12.7C Min 9.3C Pptn 6.8 mm] .


The rather wet month ended with a total of 135.6 mm of rain (213%) & [159%] of averages, most in 10-years and the 8th largest in March since 1928. Largest since 2006. A warm month the mean 8.3C (+1.6) & [+1.3] of averages, but sunshine was at a premium at Valley least since 2006 and ranked 32 on the Anglesey record.


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April 2017

April 1 - began mostly cloudy after a moderate shower of rain (5.8 mm/h) at 0536 GMT although now bright with some sunshine breaking through, somewhat misty visibility. Pressure 1007 mb was rising with a ridge to the W of Ireland from Atlantic-high 1027 mb lying off Iberia. The cloud was due to complex bands associated with a minor low 1003 mb over Wales. When the sun appeared it was quite pleasant; several large bumblebees were about the garden and from time to time disappearing under ground often into holes in the grass sward that for me are very difficult to spot, but for bees it seems no problem. Later they will pop up again from the 'invisible' hole hidden in the grass, they seem to like to build their nests in old tunnels left by moles which are frequent in the garden. (Gravesend 17.6C Lake Vyrnwy 22.4 mm) {Max 14.3C Min 8.0C Rain 0.3 mm].

View of Snowdonia from Llansadwrn.

The ridge if high-pressure moved across in the night, bright stars were visible at midnight on the 2nd and as a result there was a touch ground frost -0.7C by morning. Very good visibility with now no seen on the tops and N-facing slopes of the Carneddau Mountains. Pressure 1023 mb was rising in the ridge over the UK from high 1027 mb near the Iberian coast moving over Cap Finisterre by 0900 GMT. Fine and sunny, but a cool 8.0C, the slight white frost on the fields had disappeared and after the clear sky convection was building to the south and west and Valley reported light showers. Here the sky cleared again to give a sunny afternoon with the butterflies putting in an appearance along with the large bumble and honey bees. [Max 14.3C Min 3.5C Grass -0.7C nil rain]. A bright, mostly sunny, but breezy morning on the 3rd with good visibility. Pressure was steady on 1022 mb with highs 1028 mb S North Sea and 1027 mb Iberia. Deep low 968 mb SE Greenland meant that isobars were tight to the NW of here. The afternoon turned cloudier and slight showers of rain developed during the evening [Max 11.5C Min 5.5C Rain 1.3 mm].Dates of flowering of bluebell in the wood in Llansadwrn 1996-2017. A fine and bright morning on the 4th with a light cool N'ly breeze, temperature 8.2C (dewpoint 5.5C). Pressure 1029 mb was rising rapidly with high 1034 mb sea area FitzRoy. Cloud had moved SE overnight and there was a frontal wave over SW UK associated with low 974 mb N of Iceland. Mostly sunny afternoon. There were several bluebell flowers out in the wood, about the same date as last year (graphic left), 3 days earlier than the median date of flowering here back to 1996. Both 10-days earlier that 2015 and equal to 2014; the earlier has been 17 March 2012. Leaves on horsechestnut are expanded and flowers have formed, but are not yet open. A few bud scales from sycamore have appeared on the ground and seeds have begun germination [Max 11.5C Min 7.3C Rain nil]. The morning of the 5th was disappointingly very dull, overcast and a cool 7.6C, there was moderate dew with the grass minimum reading 0.0C, so no frost. Pressure was on 1034 mb with a high 1037 mb off SW Ireland. The afternoon was brighter with a little sunshine breaking through [Max 11.7C Min 4.3C Grass 0.0C Rain nil].

Meteosat MSG image (c) EUMETSAT at 15 GMT on 06 April 2017, courtesy of Bernard Burton. Another cool dull day on the 6th with skies overcast giving 'anticyclonic gloom'. Pressure was steady on 1033 mb with high 1034 mb over SW UK and Ireland. There was no change in the blanket of cloud and the day remained sunless. Not so in S Wales, S England and France where it was mostly sunny. [Exeter 12.5h St Athan 11.5h Bordeaux 12.4h Valley nil] [Max 10.6C Min 4.7C Grass 0.2C Rain nil]. A bit brighter on the 7th with a patch of blue sky seen at 0900 GMT. Keeping dry, and seemingly cool although a little above the averages for the beginning of April here. After an overnight minimum of 6.7C a temperature of 8.9C to begin the morning and rising to 13.6C after noon when it had become sunny, a day mean of 10.2 (+0.9) & [1.2]. High 1029 mb was now over Cardigan Bay with the same pressure in Llansadwrn. Wisley 18.8C Cardiff 16.8C Camborne 12.6h St Athan 12.4h Valley 6.1h]. Overnight the cloud had moved away and on the 8th it was one of those rare clear sky mornings. It was to be a perfect day with wall to wall sunshine, a light NE'ly breeze Hampton WW 21.4C Trawsgoed 20.7C Charterhall 12.8h Lake Vyrnwy 12.7h [Max 18.8C Min 3.0C Grass -1.7C Rain nil]. There was some cloud in the sky on the 9th, 5 oktas, with moderate visibility in thick haze recorded as smoke, a pollution haze developed as a result of sunlight on atmospheric pollutants resulting in elevated concentrations of ozone. The monitor high up on Marchlyn Mawr at 2100 ft where an instrument recording ozone (Welsh Air Quality Forum) measured nearly 120 µg per m-3 . The morning turned cloudier from the west and the afternoon had little in the way of sunshine Cambridge 25.5C Aberdaron 11.5C Shoeburyness 12.6C Valley 2.5h [Max 14.4C Min 9.1C Rain nil]...

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Select individual 2016 graphic below, or see most on a page Weather graphics 2015..

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Graph of daily mean temperature. Graph of daily maximum and minimum temperatures. Graph of soil temperature at 30 cm depth. Graph of daily rainfall. Histogram of monthly rainfall compared with the long-term average. Histogram of accumulated monthly rainfall with comparisons. Daily global solar radiation in Llansadwrn (midnight to midnight) Anglesey sunshine: Source of original data (provisional) SYNOP reports Valley Met Office. Graph showing net yield of a mown grass ecosystem at the weather station. Red graph is total yield; Green graph is rate of growth. Comparison of annual grass production since 2004. Histogram of potential evapotranspiration and water balance. Soil moisture percentage (% dry mass).


Select individual 2015 graphic below, or see most on a page Weather graphics 2015..

Hover your cursor over the icon for details

Graph of daily mean temperature. Graph of daily maximum and minimum temperatures. Graph of soil temperature at 30 cm depth. Graph of daily rainfall. Histogram of monthly rainfall compared with the long-term average. Histogram of accumulated monthly rainfall with comparisons. Daily global solar radiation in Llansadwrn (midnight to midnight) Anglesey sunshine: Source of original data (provisional) SYNOP reports Valley Met Office. Anglesey hourly mean wind wind: Source of original data (provisional) METAR reports Valley Met Office. Graph showing net yield of a mown grass ecosystem at the weather station. Red graph is total yield; Green graph is rate of growth. Comparison of annual grass production since 2004. Histogram of potential evapotranspiration and water balance. Soil moisture percentage (% dry mass).


Some annual stats when available are below

Graph of annual mean temperature and anomalies 1979-2016. No. of winter air frosts in Llansadwrn. Annual rainfall anomaly at Llansadwrn 1929-2014. Anglesey annual sunshine anomaly 1931-2014. Number of days with gales recorded in December and January on Anglesey.


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Large [260 KB] NOAA 12 visible image at 1623 GMT on 8 April 2002 showing a cloud-free British Isles. Courtesy of Michael Wienzek ( A rare cloud-free image of the British Isles captured by the NOAA 12 satellite at 1623 GMT on 8 April 2002.

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