UHI Mahara

Dr. Eddy Graham's Hebridean Weather Blog

by Dr. Eddy Graham

High Summer and Phytoplankton

Make no mistake... high summer has arrived on the Isles.. what a glorious few days of weather we've been having these past few days !

And together with the magnificent clear skies, the NASA satellite today has picked up what seems to be a beautiful cyan Phytoplankton bloom off the north coast of Scotland (see image below).

Phytoplankton are microscopic sea plants that grow in especially think densities when bright sunshine interacts with nutrients caused by the upwelling of cold waters (which sometimes happens around western coasts of the British Isles during spring and early summer).

Image courtesy NASA/MODIS

Eddie, Stornoway, 10 July 2014.


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Posted by Dr. Eddy Graham on 10 July 2014, 11:44 PM | Comments (0)

"Tour de Hebrides": Sunshine, Thunderstorms and Hail for Audax 2014

Experiencing nearly all the elements in one day, the first Audax Hebrides 110km cycle challenge took place today on Lewis and Harris (a kind of Hebridean "Tour de France").

Leaving Stornoway ay 10a.m., fine sunshine soon gave way to showers (spawning repeatedly from the Clisham) on the route down to Kershader - some later groups of cyclists got soaked indeed. However, we were greeted with warm sunshine & dry conditions when arriving at the Ravenspoint Centre, South Lochs for checkpoint #1.

It was then back up on the bikes in the warm sunshine to Leurbost and the left turn for Calanais, only to be hit by a stupendous hailstorm and flashfloods at Achmore (where the spray & wash from passing cars completely drenched us cyclists!.

Arriving at Calanais visitor centre for checkpoint #2, we were rewarded with beautifully warm hot chocolate (with cinnamon) and banana cake. Then onto the serendipitous Blue Pig Studio in Carloway (what a marvellous place!), where Aoife had made yet another glorious cake to eat and share! Whilst, there there was another almighty downpour of rain and hail, & a crack of thunder too!

For the final high-speed leg back to Stornoway across the Pentland Road, the sun shone and I was almost dry on arrival at the Bridge Centre.

You can see the contrasting weather in these photographs I took from Achmore, shortly before the hailstorm hit at 1:30pm. Also, the NASA satellite image for today (following image) shows sunny Point and South Lochs, whilst the thunder clouds were building over the hills.


With great thanks to Audax Hebrides and Ian Gilbert - a great day for all

Eddy, Stornoway, 5/7/2014

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Posted by Dr. Eddy Graham on 05 July 2014, 9:04 PM | Comments (0)

Stornoway Weather June 2014 - mildest since 1970 but dull (lack of sun)

Stornoway during June 2014: Mild, dull and rather dry

I've just worked out the weather statistics for the month past (June 2014):

 - With an average daily high of 16.1degC and average daily low of 10.7degC, it was the mildest June since 1970 

 - It was also the 3rd mildest June in 141 years of recorded weather observations in Stornoway (after 1970 and 1940)

 - It was disappointingly dull with only 141 hours of total sunshine (80% of average, and about a 1 in 5 chance of occurrence)

Well, I'll finish with this stunner of a satellite image from NASA of the Hebrides yesterday (Tuesday 1st July) - a "cracker" of a day - let's hope the summer has more days like this in store!

Eddy, Stornoway, 2 July 2014

Attached files:
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Posted by Dr. Eddy Graham on 02 July 2014, 10:00 PM | Comments (0)

Rain and fresh winds set to return this week

After more than 3 weeks of mostly dry weather across the Isles, rain & fresh winds from the west and south-west are set to return by the middle of this week.

Expect a good spell of steady rain on Wednesday, accompanied by fresh SW winds. Expect showers with lighter winds on Thursday, but heavy rain and the risk of strong winds will arrive on Friday - well hey, summer has arrived on the Isles!

E., 30/6/2014, 10a.m.

Posted by Dr. Eddy Graham on 30 June 2014, 9:45 AM | Comments (0)

Final St. Kilda Swim Weather Forecast

Wed 2nd July 2014 final news:

Alas - the swimmers never made it, the northerly swell proved too difficult and dangerous to continue - a brave attempt nonetheless!

Update Monday 30/6/2014: The swimmers are nearly there! (You can track their progress at: http://stkildaswim.weebly.com/follow-us-live.html

Hi folks

Ok, here's your final forecast  - please read carefully as the timeframe of the weather window appears to be closing...


E. 27/6/1014, 09h30



Attached files:
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Posted by Dr. Eddy Graham on 27 June 2014, 9:42 AM | Comments (0)

Provisionally the dullest May-June since 1944

STOP PRESS!  (26 June 2014): At long last,  the month of June has redeemed itself somewhat over the past few days with welcome spells of glorious sunshine for most - so let's wait & see what the final sunshine total is at the end of the month before making any  further definitive statements.

As of today (Monday 23rd June) it has been (provisionally) the dullest combined May & June since 1944 in Stornoway. Only 217 hours of sunshine have been recorded at the Airport since 1st May (about the same that we might expect for the whole of May alone).

The following graph shows the sunshine totals for May & June combined since sunshine measurements began in Stornoway in 1929. One can see that there has been less than half the number of sunshine hours this year, when compared to the same period in 1976 (473 hours) or 2009 (452 hours).

One can only hope that the promised sunshine for later this week & coming weekend materialise!

Eddy, Stornoway, 23/6/2014



Attached files:
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Posted by Dr. Eddy Graham on 23 June 2014, 11:38 AM | Comments (0)

Swimming to St. Kilda: Weather to Play Key Role

N.B. Latest Eddy-Weather Forecast for the Swimmers at: Weather Forecast

In the true spirit of adventure and in the constant striving for the highest goals in life, this summer has already seen some incredibly brave feats, all in the aid of charity. For example, Niall Iain Macdonald has bravely attempted to row single-handedly across the Atlantic; soon there will be further endeavour by a group of 9 swimmers  to swim relay-style from the Isle of Harris to St. Kilda in the Outer Hebrides (The St. Kilda Swim 2014), a distance of 56 nautical miles across the roughest and most treacherous stretch of water in northwestern Europe.

Not since Tim Severin sailed The Brendan across in Atlantic in 1976 have we seen a summer like it!

This stretch of water is notoriously harsh and unpredictable. Huge swells travelling from thousands of miles away (such as from the Caribbean) are a frequent occurrence.

Current weather predictions show a possible window of high pressure (and therefore reduced swell and smaller waves) from the present through to next week (last week of June) when the swimmers hope to begin their undertaking.

You can follow the latest news from the St. Kilda Swim team on twitter at: https://twitter.com/TheStKildaSwim2 and donate online to excellent causes at: http://www.stkildaswim.co.uk/

Eddy, Stornoway, 18th June 2014


Attached files:
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Posted by Dr. Eddy Graham on 18 June 2014, 2:28 PM | Comments (0)

It's Noctilucent Cloud Season

Noctilucent, or “night-shining” clouds are the highest type of cloud, forming at a height of 80km in the Earth’s atmosphere. Here, the air is so thin that the atmospheric pressure is three hundred times lower than that at the top of Mount Everest, and air temperatures are an incredible minus 130°C.

Noctilucent clouds can be spotted on clear nights close to the north or north-western horizon during the months of June and July - so the time is now ripe for spotting them!

Here's a pic of one I took from Sabhal Mor Ostaig on the Isle of Skye in summer 2012:

Why are Noctiulcent clouds blue in colour?

Their magnificent blue colour is caused by the absorption of light by ozone. Occasionally they may also appear a bright pearly white as well, as the clouds are made up of billions of tiny ice crystals which brilliantly reflect light. Often, they have a tenous and wavy appearance, with spectacular ripples moving through the clouds at times, like breaking waves.

Why can see them only in June and July?
Due to their great height, the clouds may remain sunlit for several hours after sunset on the Earth’s surface, as the sun itself is not far below the horizon during the northern summer (and indeed remains above the horizon within the Arctic Circle). 

Are they becoming more frequent?
Noctilucent clouds have become more frequent during the 20th century, and there are no known observations of them before the late 19th century. The co-incidence of increased sightings with progression of the industrial age has led many scientists to believe that they are linked to global warming and climate change. Indeed, 2013 saw one of earliest and most widespread displays of noctilucent clouds ever recorded.

How is water vapour getting up so high in the atmosphere?
At a height of 80km, noctilucent clouds are far above the main clouds that produce our weather and thus the water vapour that forms noctilucent clouds cannot have been advected so high into the atmosphere by normal weather systems alone. 

Recently, NASA satellites have shown that that the formation of these clouds is controlled by the amount of debris and ash produced by the burning up of meteors (coming from space) in the Earth’s upper atmosphere.

So have a look out over the coming weeks and keep your eyes peeled for these clouds, which can usually be spotted close to the north-western horizon from midnight onwards; please report all sightings to edward.graham@uhi.ac.uk (twitter: @eddy_weather)

More info on noctilucent clouds can be found at:

Eddy, Stornoway, 17th June 2014

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Posted by Dr. Eddy Graham on 17 June 2014, 2:32 PM | Comments (0)

Thunderstorms, Tornadoes and Beaver's Tails...

Two tornadoes formed near Pabbay in the Sound of Harris, yesterday (Tuesday 10th June) during a violent thunderstorm with hail. There were also severe thunderstorms in the Minch and over N Lewis later (see YouTube link below).

Photos kindly provided by Raymond Campbell:

See https://www.facebook.com/groups/isleofharris/permalink/10152251742722946/ for more.

I also captured a time-lapse sequence of a "beaver's tail" (incipient funnel cloud) over the War Memorial, Stornoway during the late afternoon: See http://youtu.be/oIqw-Bx0Y-o

Eddy, 11/6/2014

Latest weather news by Eddy on: https://twitter.com/eddy_weather

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Posted by Dr. Eddy Graham on 11 June 2014, 12:17 PM | Comments (0)

Weekend Weather Cracker

What a cracker of a weekend of weather! (And in some places, there literally were some ending cracks... of thunder!)

Here's what the NASA satellite saw when passing over us earlier Sunday afternoon (note the lovely streamer of cumulus cloud set off northwards by Beinn Mhor and Hekla in South Uist) - also big thunder showers were developing at the same time over Caithness and Sutherland).

(Bha Beinn Mhor & Hecla a' deanamh loinne de sgothan breagha an 'diugh ann an Uibhist a Dheas)..

Highest temps as follows: (Generally Sat was slightly warmer, but 19-20C was reached widely on both days)

Stornoway town: 19.7C (Sat)

Stornoway Airport: 19.9C (Sat)

Skye: 21.5C (Sat)

Orkney: 18.4C (Sun) - wow!

Aultbea: 21.8C (Sat)

Inverness: 21.9C (Sat)

Eddy, Sunday 8/6/2014, 9pm

Attached files:
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Posted by Dr. Eddy Graham on 08 June 2014, 8:50 PM | Comments (0)

Sunshine, Heat and Fairy Whirlwinds

Writing in Béaloideas in 2007, Daniel Giraudon gives a description of  the various superstitions associated with "fairy whirlwinds" in the Celtic culture of Brittany (Breton) of north-west France. Similar legends permeate deeply in Irish culture - on two separate occasions in the past (both whilst in the "magical" land of  Connemara), I have witnessed fairy-whirlwinds, and experienced their mistifying but destructive presence. It was on one of these occasions in August 1986, on the summit of Maol Reidh (Mweelrea, 2688ft), Mayo, Ireland) where I first encountered one; rather coincidentally Michael Viney (1979) also describes an encounter with a fairy whirlwindat the same spot in late 1970s.

And so it was whilst peatcutting on a fine evening recently with my family just off the Pentland Road (near Stornoway), that we were visited by a Fairy Whirlwind!

I heard it coming (for they make a very distinctive "football clacking" sound) - it blew over my bicycle as it whipped across the moor, its centre passing just 20-30 feet from ourselves. My wee balach, Brendan (4), became frightened and scared -  but really there was nothing much to fear on this occasion, apart from its invisible presence which was ghostily impressed upon the swirling heather and grasses.

What are Fairy Whirlwinds? 

(Photo Laura Smith http://www.photogalaxy.com/photo/smithyla/1/)

I won't slay a beautiful mystery with a hard and cold fact here - but suffice to say that fairy whirlwinds are possibly close cousins of the desert dust-devil. But since most "dust" on the moor is very wet peatbog - we get the devil but not the dust!

Oiche mhath agaibh, a cairdean!

Eddie, Stornoway, Friday 6/6/2014

Highest temps on Sat 7th June as follows: Stornoway town: 19.7C, Airport 19.9C, Skye: 21.5C, Aultbea (Wester Ross) 21.8C. Follow me on twitter for all latest weather news: https://twitter.com/eddy_weather


Giraudon, D. (2007). Supernatural Whirlwinds in the Folklore of Celtic Countries.Béaloideas 75, 1-23.

Viney, M (1979). Another Life. Dublin: The Irish Times.

Attached files:
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Posted by Dr. Eddy Graham on 06 June 2014, 5:00 PM | Comments (0)

Dullest May for over 30 years

May is normally the sunniest month of the year in the Hebrides with an average of over 200 hours of sunshine for the month as a whole - but this year’s total fell far short of that, with a disappointing total of only 124 hours recorded in Stornoway. This makes it the dullest May since 1986, and 4th dullest May within the last 84 years.
On the plus side, it was another warmer month than normal, with no more than an average amount of rainfall.

Average daily high: 12.6°C (Highest: 17.7°C on 27th)
Average daily low: 7.4°C (Lowest: 1.4°C on 14th)
Deviation of temperature from normal: +0.7°C
Total rainfall: 74.6mm (2.93in) – about normal
Wettest day: 18.8mm (0.74in) on 21st
Days with rain (>1mm): 16
Max wind gust: 49mph on 16th
Total Sunshine: 124.3 hours (only 61% of normal)

Posted by Dr. Eddy Graham on 02 June 2014, 4:48 PM | Comments (0)

Ne'er cast a clout til May be oot!

What a disappointment May has been weatherwise! Normally the sunniest month of the year in the Hebrides with an average of over 200 hours of sunshine, this year we are struggling to even surpass the sunshine total for April... and it's COLD! (a daytime high of only 8.2degC on Wednesday last, which is about the average for early March).

The 24 hours to 8a.m. on Thursday 22nd May recorded 18.8mm (0.74in) of rain - a nice jolly total (as if any of us needed reminding). Bha e gu-math fluich!

Eddy, 23/5/2014, 9:10a.m.


Posted by Dr. Eddy Graham on 23 May 2014, 9:10 AM | Comments (0)

Classic cirrus hydraulic jump over Great Glen

A NASA satellite image of Highland Scotland yesterday (16 May 2014) shows a classic hydraulic jump of cirrus being generated after a stable downslope flow into the Great Glen (marked roughly by the line of clear skies running down the centre of image). When this happens, the upper flow suddenly reaches the super-critical point for laminar flow and "jumps" up in the atmosphere (a hydraulic jump), generating a sheath of cirrus - the ice of which appears orange in this enhanced image.

Image courtesy MODIS-NASA.


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Posted by Dr. Eddy Graham on 16 May 2014, 9:22 AM | Comments (0)

Much rain for weekend (17th May)

Tomorrow Saturday 17th May is the national holiday of Norway... and in true Bergenese fjordic (west Norway) style... we're gonna get rather wet this weekend.

Expect 2-3 hours of steady rain this afternoon (Friday) accompanied by continuing gusty and strong SW winds, clearing by late evening - but more rain's on the way tomorrow (Saturday). Hopefully it will stay off until the afternoon and end of the Women's 10k run in the Lews Castle Grounds, Stornoway. But expect persistent and possibly heavy rain later in the afternoon and evening however, though winds will fall much lighter,

More rain Sunday, but then turning warm and bright for a few days from late Monday/Tuesday, as winds back south-easterly.

Eddy, 16.5.2014, 9:10am


Posted by Dr. Eddy Graham on 16 May 2014, 9:10 AM | Comments (0)

Fine till Wed - Milder but damper thereafter

Weather Forecast for Week Beginning Monday 12th May 2014:

Fine and dry for today (Monday) and tomorrow (Tues), but feeling cool along east-facing coasts with a fresh NW breeze blowing down the Minch.

Milder and warmer from later Tuesday/Wednesday, but increasing cloud by Wednesday bringing periods of mist, drizzle, cloud and mostly light rain (getting heavier by the close of the week) - and freshening SW winds too, perhaps becoming strong SW on W coasts by the end of the week - oh dear!

Eddy, Stornoway, 12/5/2014, 8:30am


Posted by Dr. Eddy Graham on 12 May 2014, 8:26 AM | Comments (0)

A very mild April - but it was warmer in both 2009 and 2011

April 2014 was very mild in Stornoway, with the average air temperature some +1.7degC above normal at Stornoway Airport. However, a quick glance at the records shows both 2009 and 2011 were milder - whether this is part of a long-term trend remains to be seen.

E.G. 5/514

Posted by Dr. Eddy Graham on 05 May 2014, 9:15 PM | Comments (0)

Remaining Unsettled

Very quickly.. but the weather will remain unsettled for much of the coming week across the Hebrides - although brighter than the dull Holiday weekend we have just had.

E. Mon. 5/514, 9pm

Posted by Dr. Eddy Graham on 05 May 2014, 9:12 PM | Comments (0)

Cloud and some rain ahead for holiday weekend (sorry...)

Despite the Sun and bright blue sky this morning in Stornoway making it feel more like the Mediterranean or south of France ("oo-la-la" says Eddy)......I'm afraid the omens are portending a gradual return to cloud and rain over the weekend for most of the Hebrides and NW & W Scotland.

Any rain will be rather light and patchy, however (mist and some drizzle is the most likely combination), and there will still be some drier periods. It will also become quite mild again (so that's some good news anyway - "alors, magnifique" says Eddy)

Remember it is May now - so we have only 3-4 weeks left before that nasty blighter, the Highland Midge makes a return... so get your peats cut soon!

N.B. A nice MODIS sat-pic of the North of Scotland on Monday 28 April 2014; note the fog over the west side of Lewis

Eddy, Stornoway, 9a.m., 2/5/2014

Attached files:
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Posted by Dr. Eddy Graham on 02 May 2014, 9:05 AM | Comments (0)

Fine weather to remain (mostly)

(Last week's forecast)...

The fine weather is likely to last for much of the coming week - though there will be a hiccup from Wed-Fri, with more cloud and a risk of short spells of rain. But overall, winds will stay in the east or south-east, meaning there's a much greater likelihood of long dry spells and fine skies continuing - with average temperatures for spring-time, though feeling warmer in direct sunshine.

Eddy, Stornoway, Monday 21 April, 12:25pm

Quick update for the Weekend (Sat 26th /Sunday 27th April):

Becoming breezy tonight and into Saturday with freshening north-east winds making it feel much cooler than of late. Some rain later tonight & tomorrow (Sat) too, sporadically heavy. Drier again for next week, with high pressure building again from the north, but becoming much colder, with even the risk of a few flurries around Wednesday/Thursday. But, overall - not too bad really!

E. 5pm, 25/4/2014

Posted by Dr. Eddy Graham on 21 April 2014, 12:22 PM | Comments (0)

Excellent Spring Convective Cloud Example - April 14, 2014

During spring, the average sea surface temperature surrounding the British Isles is only about 7-10degC, which is very cool relative to the temperature of the land surface during the day (which may get heated by strong spring sunshine to 15 or 20degC).

This combination of supressed sea-surface temperature and increased land surface temperature causes air thermals to bubble-up quickly over land during daytime, leading to the familiar cumulus clouds ("cotton-wool puffs") of an April afternoon.

This phenomenon was displayed magnificently over Ireland, Wales, England and southern Scotland yesterday, 14 April 2014 - being captured by the US NASA MODIS satellite sensor in space, as it orbited over the UK and Ireland -see image below.


N.B. Note the clear skies over the seas, but bubbles of white cumulus cloud over most land areas.


Attached files:
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Posted by Dr. Eddy Graham on 15 April 2014, 11:26 AM | Comments (0)

Warm, hazy spell to continue

it won't be wall-to-wall sunshine everyday during this coming week (Mon 31.3.14 onwards), but the reasonably settled spell of weather looks like continuing across the Hebrides and Isles.

Expect a little rain Monday night into early Tuesday, and again perhaps later in the week, but overall the breeze will stay in an east or south-easterly direction bringing much sunshine and warm conditions (temperatures could even reach well into the teens degC). It will remain hazy during the first part of the week, perhaps freshening up by the end of the week.

Eddie, Stornoway, 30.03.2014

Posted by Dr. Eddy Graham on 30 March 2014, 10:52 PM | Comments (0)

Spring sunshine on the way (at last!)

At long, long last, some glorious spring sunshine is likely on the way later this week... but not after a short "hiccup" of an interruption Monday/Tuesday...

From Tuesday/Wednesday onwards, I am expecting fine weather, offshore easterly winds and glorious sunshine for a few days at least. Hopefully, this should brighten everyone's spirits, especially after us having to endure such dastardly weather for the past 4-5 months - it has even put grey hairs (..ahem blonde..?) on many a meteorologist's head... :)

Note on Today's "Sunday Snowflakes": Yes indeedy, a veritable whirl of Mother Nature's confetti blew down upon us for a few minutes this morning - but it's hardly worth a second-mention, as the rest of the day was fine and sunny, although the north wind stayed cold and treacherous. Here's a pic of the view from Gress Beach this afternoon by Eddie (23/3/2014):

Eddie, on World Meteorological Day 2014

Attached files:
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Posted by Dr. Eddy Graham on 23 March 2014, 9:59 PM | Comments (0)

Wind speeds and Rain Totals for Wednesday

It was one of the wettest 24 hours in March in Stornoway for many years, with a total rainfall of 32.2mmm (1.27in). And wettest of all in the Hebrides was Lusa bridge (near Broadford) on Skye with 46.0mm (1.80in).

Max wind gusts were, as expected, 61mph at both Stornoway and South Uist.

There were intermittent power cuts during the evening across many communities.

Eddy, 10h05, Thursday 20 March 2014

P.S. Focus is now on much colder weather for a couple of days with snow flurries

Posted by Dr. Eddy Graham on 20 March 2014, 10:08 AM | Comments (0)

Severe gales Wednesday & Thursday

Update (Wed 11h30): I'm still expecting a strong gale to develop later today (this evening and overnight till the early hours of Thursday), accompanied by heavy rain. Gusts to 60mph are still possible. Snow and soft hail showers will follow by early Friday, but any snow is unlikely to be persistent or lie for long (except on hills).

Original Post (of Tuesday) continued...:

Another severe southerly gale is likely to pick-up through the Minch tomorrow (Wed) - average wind speeds may reach severe gale force 9 (or possibly even storm force 10 briefly), with gusts 60-70mph. Later Wednesday night into Thursday, the winds will die back temporarily, before veering southwesterly to westerly and increasing again during Thursday, with more severe gales off the Butt of Lewis.

Heavy rain is likely too, with the weather turning much colder from Thursday onwards as winds further veer northerly (but easing considerably), and snow could be seen right down to sea-level by Friday in many places.

Eddy, Stornoway, Tues. 18/3/2014

Posted by Dr. Eddy Graham on 18 March 2014, 2:34 PM | Comments (0)
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